Sunday, December 30, 2012

Adapter required for Euro L-1000T

The European Kenwood L-1000T (and I get the feeling that most of them sold in Europe, as FM was out-of-fashion when the fantastic L-1000T was introduced) requires this particular adapter, or so it seems right now:

PAL Male to F-Connector (Coax) Female
Radio Shack #278-261

"PAL adapter" for short.

Unfortunately, after adding a second adapter to the B input, the B input still cannot be selected.  I'm not sure if this is because I don't have the correct remote, I was thinking it would auto-select the B input if stronger, but I couldn't find any station where that happened.

Wednesday, December 26, 2012

Remote Control for FM in every room

When my 4 day Chrismas holiday began, I had only one remote for controlling my wonderful Kenwood L-1000T FM tuner, and it only worked in the living room aimed in a very tricky way at the actual L-1000T because of how it is tucked behind the speaker.  I had to reach and wave the remote until it finally worked.  I did have a learning programmable remote control that I had never gotten to work, and another brand name programmable remote still in it's packaging.  Without remote control, it's is not desireable to scan FM channels but rather simply to keep it fixed to just one favorite, which can get boring particularly over a Christmas holiday...

Now I have easy remote control of the L-1000T in the living room, and in the bedroom and kitchen as well, through my network of remote control extenders.  Remote control extenders receive a remote control infrared signal in one room, send it via radio signals to another room, and then transmit the infrared signal toward the equipment that is to be controlled.  Most of the ones I use are from Radio Shack and they are small black rounded pyramids with short antennas.

And now I also have two working remotes, one being the Sony RM-VL610 learning programmable remote that had never worked before (now I can't find the unopened one).  I've spent much time listening to different stations in bedroom and kitchen.  With just one control, it is almost always in the wrong room, but with two remote controls I can have one in kitchen and one in bedroom, so they are always there, I don't have to remember to carry it with me.

The trick was finding the instruction manual to the Sony learning remote, and successfully getting it to learn the L-1000t remote codes.  Even with the instructions, it was tricky because the instructions themselves are not very clear in parts.  It's often unclear when you simply press buttons as opposed to holding them, or vice versa, and when you are supposed to let go.  In fact, in one particular case, you are supposed to hold a button, and the manual just says "press" and not "press and hold" but if you read to the end of the section, in the Notes section it tells you that you are really supposed to "press and hold".  Actually, it works either way, most of the time, which makes things even more confusing.

Once I had programmed the remote, which I was doing in the kitchen, I found it worked through the kitchen wireless remote receiver.  And then I tested it using the bedroom, and voila, the programmable remote actually worked better in the bedroom than the actual Kenwood remote.  So I could use the Kenwood remote in the Kitchen (or living room) and the Sony in the bedroom.  I then found I could program buttons on the Sony to control the HDMI switch in the kitchen (something that I had tried but never been able to do before) and also the Samsung TV in the bedroom (another thing that I had tried but was never able to do before).  So I'm on my way toward being able to use this programmable remote to control many things, making bedroom remote control life in bed far easier.

One other thing I had to do before I made any progress was to re-orient the remote control transmitter in front of the L-1000T.  The current orientation of the L-1000T and the remote extender are shown in the photo above, the remote extender is in the lower left corner on top of a pile of collectable Allied Radio catalogs which boosts it to the correct height.  Sometime in the past few weeks I had been trying to remote control the L-1000T directly, thinking the remote extenders were not letting me get at all the obscure functions.  So I had angled the L-1000T badly for the remote transmitter so it was not working at all.  So I had to do a lot of fiddling with the angle of the Kenwood and the angle of the remote transmitter to get it to work again.  It mostly didn't work from the bedroom, but it did work from the kitchen, after much fiddling.  I tried attaching a bunch of tie slips to the antenna on the transmitter to make it work better in the bedroom, but that approach didn't help.  I was finding I could use the Kenwood remote in the bedroom so long as I as standing right next to the bedstand light in a particular spot.  As inconvenient as this was, at least it verified that the remote control extenders were working correctly.  It took using the Sony programmable remote for reliable and easy bedroom operation.  One can guess that the Sony programmable remote puts out a higher signal level than the Kenwood remote, and that makes it work better through wireless extenders.  Or, perhaps it puts out a "clarified" signal with exaggerated on/off edges, the kind of thing you get when you use a "sharpness" control on some TV's.

A learning programmable remote is absolutely required for this application.  Programmable remote controls with a bunch of presets never or almost never have settings for extremely rare components like the Kenwood L-1000T tuner.  But since preset types are much easier to use than learning types, preset remotes have mostly driven learning remotes off the shelves.

Monday, December 24, 2012

making more of the L-1000T

In the early hours of December 24, I finally hooked up the Lavry AD10 digitizer to the Behringer DEQ 2496 which applies EQ correction for my European L-1000T.  I used a Monster Standard 8 foot optical cable.  With that digital connection, I was able to bypass the inferior digitizer at the input of the Behringer itself, and therefore enjoy the benefits of the better Lavry digitizer in other rooms, when listening to the L-1000T remotely using my Sonos system.  It also allows me to select the L-1000T in the living room without having to change the EQ mode of the DCX crossover, which can also perform the EQ correction, and yet still enjoy the benefits of the Lavry front end.

The benefits of this change seemed clearly audible in other rooms, which previously could not enjoy the benefits of the Lavry at all.  In the living room, I could previously, and can still, listen straight from the Lavry into the AES input of my Tact.  When I listen that way, I have to get up and turn the EQ mode of the crossover from OFF to ON.  That setup still seems to provide the last nth degree of performance, seeming to have slightly better incredibly real 3D imaging.  But it's a pain to get up and turn the EQ mode of the crossover on and off, far simpler just to switch inputs on the Tact, where I can select the digital output of the DEQ as input.

As compared with using the digital input of the Behringer, using the Lavry provides an especially musical sound, with utterly transparent but non-electronic sounding midrange.  By comparison, the Behringer has a slightly etched sounding midrange that sounds like hifi reproduction, not real music.

It's funny how (or if) I can hear this even going through a second level of digitization in the Sonos system itself.  Sonos lets me listen to line inputs from every room having a Sonos box.  The Sonos line input must be an analog input, which is then digitized to 44.1khz by the box and transmitted through digital signals on the CAT-5 cables that connect all rooms in my house.  Each other Sonos box can pick up this signal and play it back through a digital output which gets fed into the Tact preamps in living room and bedroom, and the Yamaha HTR-5790 receiver in the Kitchen.  When listening to the L-1000T in the bedroom, for example, here is the chain of connections:

Kenwood L-1000T source, using variable output adjusted to within 3dB of Lavry dynamic range
6 ft Radio Shack RCA cable
dB systems selector switch with Teflon jacks
0.5 meter Cardas crosslink cable
unbalanced-to-balanced adapter plugs
Lavry AD10, which samples produces optical digital output at 24/96
Monster Standard 8ft optical cable
Behringer 2496 DEQ programmed to correct European 50uS to 75uS (slight treble shelving)
Balanced-to-unbalanced audio adapter plugs
6 ft Radio Shack RCA cable
Sonos 80 analog input in Living Room
CAT-5 cables and switches
Sonos 80 digital output in bedroom
Blue Jeans digital coax connector
Tact Preamp digital input
...Behringer DEQ for EQ and DCX for crossover
Parasound HCA-1500 power amp
Revel M20 monitors
SVS 1642 plus subs (connected to DCX)

Yes, it goes through all this stuff, but mostly in transparent digital.  With the Lavry at the front end, it all sounds so good you could imagine a direct analog electronic connection to the original source.  The fact that it's all going through a second level of analog-to-digital conversion in the Sonos 80 is not audibly apparent.

The Lavry and Behringer are connected at 24 bit 96 kHz digital.  When I'm listening in the living room, I can either select the Lavry directly from the Tact, or connect to the optical digital output of the Behringer--in which case the Behringer is being used in pure digital mode, with digital input from the Lavry and digital output to the Tact.

I bought the Monster Standard 8ft optical cable at Radio Shack a few weeks ago.  It has a sticker on the plastic case it came in saying "E-Z Open Package."  It was easier than some, but still a big pain.  It took a fair amount of torque to get the back plastic panel of the package to tear off, and as it was tearing off tiny pieces of plastic and paper (from the E-Z Open sticker itself!) flew off.  I had to wipe down my leather chair afterwards to brush off the specks of plastic and paper.  And then, the package still didn't open enough to remove the cable ends, which were held behind a second plastic panel.  After many attempts, I finally got the second plastic panel to tear off, removing the cable ends, and without tearing the cable apart.  Once again, this produced tiny bits of plastic flying through the air, but this time I was no where near my chair.  Then, the cable itself was held together with a soft plastic wrap that did not tear or easily unwrap.  I had to use the tiny scissors from my Swiss Army knife to gut the plastic strip without damaging the cable.

This is a HUGE contrast to what was a truly easy open plastic package, the package that my $400 list price Nordost Baldur balanced cables came in.  It did indeed snap right open, and without apparently producing tiny bits of plastic and paper,   And the inner plastic retainer panel was then held in with friction and could easily be pulled out or put back.  Once opened like this, the Nordost box was re-useable.  The cables were held together with soft re-useable velcro tape.  In contrast, the Monster box now fully pulled apart is clearly a piece of trash (having a very vague resemblance to the jaws of a shark) featuring rough edges that you never want to see again.

Aside from the considerable difference in list price, another feature of the Nordost cables is that they are made-in-the-USA.

And then nothing beats the ease of opening Cardas cables, which come in a large but very heavy duty ziplock style bag.  Also made-in-the-USA of course.

Somehow when you pay the extra bucks for a true premium made-in-USA cable, you get nice packaging as part of the deal.

One of the reasons I had been slow in making this change, was that I often like to keep the Kurzweil K2661 keyboard connected to the living room system, also through the Lavry.  If I have the keyboard selected in the living room, as I often do, I couldn't listen to the L-1000T without going into the living room and changing the selection on the dB systems selector switch.

Well I decided that it would be OK to listen to the K2661 through the less high quality line input of the Tact, which has 16 bits of resolution according to Stereophile.  Note that the balanced output of the K2661 first goes through a Jensen ISOLINK transformer to change to unbalanced.  With that connection, unfortunately, I have to turn the volume way up because the output is apparently quite a bit lower than the 1.6V max input of the Tact with most program.  I'm thinking of putting another line amplifier in between, such as the Classe CP-35 I am not currently using.

Wednesday, December 12, 2012

Test Patterns

Here is a discussion of analog and digital video resolution and links to test patterns.

The pattern I used  pattern seemed to show 525 line video resolution in 480i displayed on my Samsung 40 inch 550 series LCD monitor displayed in 16:9, using Mac Mini mini DisplayPort output through component video adapter into Sony RDR-HX900 which serves as analog video selector, then into a DVDO which converts to digital at 1080i, thence to HDMI throughout my house.

I was thinking 525 was a limit but it's actually 540.  But quite possibly 525 is more practically achievable.  Anyway, this is quite good for a 480i component video display.

I did find that reducing sharpness to zero or at least below 10 gave the best display on the Samsung.  That is what you generally find with digitally perfect images.  "Sharpness" doesn't add real resolution, it only adds artifacts which appear like resolution with a very lousy picture.

But hooked up this way, there was visible jittering in the top 1/10 of the picture.  The jittering was not very visible from a distance, but appears to make picture softer.

Wednesday, December 5, 2012

HDMI handshaking

Well I've often wondered what HDMI interfaces actually do in the seconds that it takes for them to make a new connection.   Here's a great discussion:[Compatibility_Mode].pdf

Here's the book, literally, on HDCP.

Here's a little Gefen EDID echoing device for solving problems like the one I had putting video from MiniDisplayPort onto my HDMI switch. (I just now bought one.)

Here's another discussion of HDMI troubleshooting at a high technical level.

The Artifacts

The artifacts I see from the Mac->Belkin->Monoprice->Sony->DVDO hookup described in last few posts, as viewed on my Samsung, are clearly interlacing artifacts, specifically the artifact known as combing.

This might or might have nothing to do with the Apple and it's output, which I have suspected is far from perfect, in 480i.  But perhaps there is nothing wrong with the Apple 480i at all.

In fact, I have another bit of evidence, this combing grows and shrinks over time, perhaps a second or so.  This suggests a possible ground loop in the connection between the Sony and the DVDO.  This would not have changed with the new Mac Mini (which, like the laptop, has two prong power connection which avoids ground loops). was previously there and I just never noticed it before.

That wouldn't necessarily explain the added softness I seem to sense compared with the S-Video output of my Titanium Powerbook.  Though perhaps I didn't pay enough attention to that before to compare fairly.  I do know that on still images especially the DVDO upscaling (as with most upscaling) gives a smoother, film-like quality compared to the brisk sharpness of 480i.

Though, I may have improved that a bit by adjusting the Underscan control in the Mac Display Preferences. Funny I did not see this control at first, and I was aggravated that it wasn't there.  Because it wasn't there, or I overlooked it, I spent more than an hour fiddling with the adjustments on the DVDO to no avail.  (For some reason, with 1080i output, the DVDO was not able to apply this underscan effect to compensate for the monitor overscan.  The Zoom and similar features could only expand the image, not make it smaller.  And changing from 16:9 and 4:3 didn't help either.

This puts more of the image on my TV screens (I've adjusted it now so you see everything) and thereby shrinks the image a bit, which makes it seem like better focus.

Still much room for improvement, and I still think the Powerbook display at 480i was much better.  The digital output to component that I am using now should be about 50% better still than the S-Video hookup, but it seems like the opposite.

I need to get some test patterns I can play through the Mac.

Tuesday, December 4, 2012

Better than expected: L-1000t over sonos

I have been listening to Kenwood L-1000T tuner, which is physically located in the living room, in other rooms using the "line input" feature of my Sonos system.

Currently this is hooked up like this:

Kenwood fixed output->Behringer DEQ 2496 (fixes eq)->Sonos box
Sonos box->system

Thus it goes through two complete analog-to-digital and digital-to-analog conversions, one inside the Behringer DEQ, and other within the Sonos system.  The latter uses 44.1Khz sampling at 16 bits.  The Behringer uses very good 96/24 converters but has rather mediocre analog circuitry.

Anyway, it sounds nice in the bedroom, and very nice in the kitchen.  I was really enjoying listening to college radio on Monday night.  Even with all the intermediaries involved, it sounds even more lively (rhythm!) than the Marantz 2130 which is actually in the Kitchen.

So here's something which shouldn't be that good, but actually is.  Actually I think digital-to-analog and analog-to-digital conversions are relatively harmless for audio.  Experiments have put 100 such conversions back-to-back and still the differences are not large enough to show up in blind testing.

I could actually hook this up using the Lavry for conversion rather than the Behringer, and I hope to do that soon.

More thoughts on the mediocre standard definintion video

I'm absolutely sure that I have seen better Standard Definition (480i) video than my Mac is now producing through the Belkin adapter (to get HDMI) and the Monoprice adapter (to get analog component).  It's very soft looking, and if I get up close, I can see weird artifacts.

480i done correctly can be a beautiful format.  It ways all most people ever knew in video until about the year 2000.  For 10 years I was the proud owner of a $3299 list price Sony TV made in 1997, a 32XBR100.  This was probably the best NTSC-only TV ever made.   It did not support any extended format features.  It did not do progressive scanning even.  But it did a perfect job of decoding NTSC from either composite (!) or S-Video inputs.  The composite inputs were decoded by one of the best Digital 3D Comb Filters ever made.  (I think the one in my later 34XBR960 is also very good.)  The 3D comb filter eliminated interlace artifacts.  In 2008, when I got a very nice 550 series Samsung 42" LCD to replace it, I was extremely disappointed that it could not eliminate interlace artifacts (from component video inputs) as well as the 32XBR100 had.  I then bought an ancient Faroudja de-interlacer (which originally sold for $15,000) and a DVDO scaler to get back what I once had.  But neither of those were as good as the Sony was either.  Neither of those expensive converters actually has a 3D comb filter.  But the DVDO is a nice unit and I still use it today to digitize analog sources onto my digital TV network.

And don't get me started on LCD vs CRT.  LCD has lagged for years the dynamic range, bright-to-dark, of old CRT sets by a country mile.  LCD has no problem with bright, but it has a problem with near-black, the so-called "shadow detail."  With fancy LED lighting schemes, LCD may be finally catching up.  I don't buy TV's often, so I'm not quite sure how good they are now.  People I talk to generally don't get that LCD is not the same as high definition.  It's just that they both came on the scene at about the same time.  And almost nobody has seen CRT TV's as good as the "XBR squared" models I have had, the 32XBR100 and the 32XBR960.

But now that we have High Definition TV, few if any manufacturers do a decent job with Standard Definition anymore.  I think that's basically the problem here.  They just can't be bothered to do it well anymore.  And they might say that nobody demands it anymore.

The 480i component video I now get is not nearly as sharp as the 480i S-Video I had been getting from my Titanium Macbook Pro, made in 2003, which had an S-Video jack right on the side.  That was also going through the DVDO adapter I am still using now.

 So where is the problem now?  I doubt that anything bad is done by the Belkin adapter which converts mini DisplayPort to HDMI.  It looks to me like this is not a conversion at all; the display port is simply carrying essentially the same lines as an HDMI cable.

It could be that there is a bandwidth limitation in the Monoprice adapter which converts HDMI to Composite Video.  But since this adapter is capable of 1080p, you would think it would have no problem with 480i.  And the box says it has 10 bit converters, that should be good too.  Many early DVD players, even the most excellent ones (like my $1500 Sony DVD-7000), had only 8 bit converters.

I have a suspicion a lot of loss is occurring in the Mac itself, via a very lossy 480i codec.  Actually, I just read this website explaining video codecs, and 480i is not a codec.  But 480x720i is a codec, and that is the one being used.  Video codecs are usually at least a little lossy.  I suspect one of two things (or both)

1) Apple didn't much bother to make a best-possible 480x720i codec.  After all, who uses that anymore?  They can't be that critical if they are still using such an old (the original) format.

2) Apple didn't want to make a good 480x720i codec.  Standard Definition video is the one video source that can be copied by all VCR's and most other video copying devices.  My Sony RDR-HX900, one of the last consumer video recorders Sony ever made, only accepts interlaced inputs in Standard Definition.  While not all electronic manufactures have interests aligned with the movie industry, none of them want to offend the movie industry either.  And one way they do this is by not making it easy, in fact making it increasingly hard, over time, to copy video, any kind of video, even when there is not active copy restriction system like HDCP in effect.  Manufacturers remember how Sony was sued by the movie industry (and Sony now *is* the movie industry, or at least one of the biggest players) for making the Betamax which could be used to record broadcast TV and movies.

3) Apple softened the 480x720i codec specifically so it would not look as bad on standard definition displays that have lousy comb filters.  Actually, only "composite video" in standard definition even needs a comb filter.  Neither S-Video nor Component Video require a comb filter.  But just in case someone might be using composite video, after all what does anyone do with 480i anymore, the codec is softened to reduce artifacts if viewed through a composite video connection.

If indeed the problem is the lossy codec that Apple uses in the Mac, I'm not sure what I can do about that.  Basically nothing unless I can find a better replacement version, which is unlikely, I am afraid.  Now in theory I could have the Mac output 1080p, and have some other device downscale to 480i.  But guess what...nobody makes scalers that downscale to 480i !!!  Or at least I have not found one.  It seems like converter makers also follow the written and unwritten rules to make 480i less and less available.  My DVDO will produce 480p (even from a 1080p source) but will not produce 480i.

But it's also possible the main limitations are in the Monoprice HDMI to composite adapter.  And in that case, I can simply use another adapter.  I will do that very soon.

Monday, December 3, 2012

Trouble and success with mini DisplayPort

On Saturday and Sunday I continued watching video through the mini DisplayPort using the 8 foot Belkin HDMI adapter.  It worked OK, but the images looked very blurry, up close you could see obvious jagged-edge type artifacts.  It seemed like I could adjust UP the sharpness control on my Sony XBR-960 TV and Samsung LCD to make it better, similar to what has been claimed on web.

This is curious because what what sharpness controls do is actually distort the picture by boosting high video frequencies, similar to the use of the Treble control on old hifi equipment.  This doesn't actually increase true resolution, it lowers it actually, but might have an objectively beneficial effect if the source has excessive high video frequency rolloff.  Has Apple somehow pre-compensated for old analog sets when it makes connections at 480i. since such sets were frequently set with high "sharpness" control settings?  Or did they just use an especially lousy 480i video codec?

But another question was why, in this setup, I was being restricted to 480i.  There were no copying devices hooked up to the system.  HDMI goes first to a 5 way switch which is about 2 years old.  Then it goes to a 4 way splitter that is about 5 years old.  All of this handles 1080i perfectly, in fact that's what it often does.  In fact it even handles 1080p, except my 2005 CRT TV does not.

Somehow, when DisplayPort sees this HDMI switch, it refuses to engage any resolution higher than 480i.  No other devices have had that problem.  I tried re-hooking, different inputs, and powering up and powering down, and fiddling with the Display preferences, but DisplayPort has decided that you have a 480i device, you only have NTSC and PAL resolutions to choose from.

I disconnected the computer, keyboard, display, mouse, and cables and took them to the bedroom and hooked directly to my 1080p Samsung TV.  THEN the display port had no problem doing 1080i or 1080p, directly to my TV.  I tried both the Belkin and Rocketfish adapters, and they worked identically in this setup.  I normally use the Rocketfish Mini DisplayPort to HDMI adapter in the bedroom with my bedroom macbook pro.

So I brought the computer and stuff back to the living room, and tried using the Rocketfish adapter.  Once again I could only get 480i.  Since the two adapters behaved identically, I think the defective "intelligence" is actually in the DisplayPort itself.  After going back to the Belden adapter, and after lots more fiddling, I was stuck with no visible output just as I had been on Thursday night.  In the worst cases, the Display preferences don't even show a second display connected.

One of my theories is that mini DisplayPort is paranoid.  It agressively downrezes to 480i if it sees anything "fishy" on the output as part of it's copy-prevention protocol which goes above and beyond HDCP.  Even just an HDMI switch can engage this feature.  Apple does says that you can use the DisplayPort output with one adapter, and no more.  A switch is not an adapter, but still enough to give DisplayPort fits.  (This theory is a bit inconsistent with my later successes, read on.  Perhaps the DisplayPort is paranoid about the wrong things.)

It's also possible that something on my video network is reporting back it's capabilities incorrectly.  But since all my other 1080i devices on the switch work fine in 1080i, I think I can fairly say that the mini DisplayPort is not acting as switch (or splitter) friendly as true HDMI components.  Thus I am not surprised at all that Apple doesn't make an actual HDMI adapter.  They may know their interface is bugged, and it may be bugged deliberately.

So this was not looking well for connecting miniDispayPort to my Sony RDR-HX900 video recorder.  That connection through the Sony was the way I used to view the computer output, as it also conveniently switches in some other 480i components, with all of them, including video stored on the Sony itself, getting converted to 1080i with my HDHO adapter on the output.

But in fact, I hooked the mini DisplayPort to a miniDisplayPort to Component Video adapter (interestingly no longer advertised on the Monoprice website, but I found it searching on Amazon) and it worked fine.  I got clear 480i direct into my Sony.  I could select 480p, but then the Sony output went dark.  I checked the Sony manual and found that while the Sony allows 480p output, it only allows 480i input.  So this is the best I could do with any adapter.  Actually, the display preferences in this case let me select up to 1080p...the Monoprice adapter works with 1080p even if my old Sony does not.  I was also able to play back videos I have downloaded from commercial erotic websites also, with no problem.  I did not try playing DVD...I have little doubt that would not work.

And most strangely, the video even looked better this way.  The jagged edges were gone.  It's possible the image doesn't have any more resolution, in fact it might have less, but I think it looks better somehow (no side by side comparison possible now).  Possibly it's because the Sony decodes 480i better than most things.  Then the Sony output goes through an Anchor Bay DVDO to generate DVI, which gets adapted to 1080i into my HDMI switch.

So after this weekend, I cannot claim not to be a happy camper.  For years I resisted upgrading my Mac fearing that I would loose my old video setup.  Now I have my old video setup back, working fine*, and it looks about as good as before if not better, driven by a computer that doesn't strain (and often crash) under the load of YouTube video like my old one did.  Technically, my old Powerbook setup used S-Video and this new one uses Component, so it could be slightly better even, and I think it does look better now, despite the earlier lousy looking 480i on HDMI.

(*The hard drive in the Sony RDR-HX900 needs replacing.  The old one keeps old recordings, but won't keep new ones.  I bought a replacement harddrive a few months ago, didn't replace it when it seemed like the old harddrive was working again, but then I found it would not keep new recordings.)

It would still be good to have a direct Mac connection to my video system through HDMI at a higher resolution than 480i, then I could watch web videos at higher resolutions than 480i.  I never had that capability before, but I can see it would be nice.  Though I fear the limitation may be with the Mac DisplayPort, my positive experince with a component video adapter bodes well that a possibility still exists.  Perhaps there is some kind of communication problem with my video network that the Mac is sensitive to, but could be fixed with a gadget like the one sold by Geffen which forces a particular description of display capabilities onto the HDMI line.

Friday, November 30, 2012

Mac Mini Setup, Phase 2

Over in my other blog, Brick Pool House, I described setting up my new Mac Mini starting on Black Friday.  It went smoothly.  But I did not hook it up to my video system because I needed an appropriate Mini DisplayPort adapter(s).

One reason I had not bought a Mini earlier, say 2-3 years ago, was because I was worried about connecting to my video system as easily as I had the PowerBook which had S-Video output.

On Wednesday and Thursday I bought various parts at Radio Shack and Best Buy.

On Thursday night I hooked up a MiniDisplayPort to HDMI adapter "cable" from Belkin, which I bought at Best Buy.  What Belkin has done is package a short cabled adapter with a 7 foot HDMI cable for $44.  You could buy the separate parts but they would end up costing more.  Plus I figured these pieces were made to go together (they are, and the inline HDMI connection fits snugly).  I only worried that the actual "converter" circuitry might not be as good as the more expensive separate options.  But I figured it was probably about the same, and this looked neat.

Well at first I plugged in the display port adapter and plugged the HDMI into my 5 way HDMI switch (which feeds a HDMI splitter which goes to TV's in 3 different rooms) it did not work.  I fiddled with it on Thursday night for more than an hour and could not get it working.  I unplugged and replugged the HDMI cable.  I turned off the kitchen TV (an older model which has 1080i, but not 1080p) and tried the Bedroom TV (a Samsung from 2008) instead.  I rebooted the Mac.  Frustratingly, the Display Preferences showed only one device, the DVI monitor, and not anything else.   However, the status light on the HDMI switch did light up.  I changed the refresh rate for the (only one shown) display to 60Hz.  I also tried changing the display preferences down to 1024x768 (very similar to 720p) and even 640x480.

I did not re-plug the Mini DisplayPort plug itself, because that was tricky.  By the end of the night, I had removed the Mini DisplayPort plug, but been unable to plug it in in the dim light, and beginning to wonder if the Thunderbolt indication meant this wasn't really a Mini DisplayPort.

All night long I was dreading the possibility that this newfangled DisplayPort thing would not work a video switch.  Apple does indeed say you should not plug any other adapters into a Mini DisplayPort adapter.  They say you should ONLY plug an approved monitor into the adapter.  This would go way beyond the normal HDCP copy restriction if you couldn't even use HDMI switches and splitters.  But maybe that's what I was not stuck with.  Perhaps I could get the old PowerBook going again with a new Hard Drive.  This was the kind of thing I was thinking, and dreading.

In the morning I checked online, and in fact the Thunderbolt plug can work like a Mini DisplayPort plug if a Mini DisplayPort adapter is plugged into it.  Looking at one set of troubleshooting instructions from Mac, I noticed that as their last step, they had you remove and reinsert the Mini DisplayPort plug after shutdown and then restart.  The instructions were a bit ambiguous as if to suggest you should try re-inserting the plug several times even.

This time I was able to re-insert the plug, and it still didn't work right off, but after a bit more fiddling, it started working, and I got good images on both kitchen and bedroom TV's at once.  The second monitor now does show up in Display Preferences and I adjusted them for side-by-side.  I set the main monitor for "best display."  For some reason, the video system only gets 640x480.  I can only choose that.  I shut off the kitchen TV again, and on my Bedroom TV I could select either 640x480 or PAL, but no HDTV like 1080p.

It must be that my switch and splitter are sending some kind of least-common-denominator display information back up the line.  All of my TV's are capable of 720p and 1080i, but my Kitchen TV only does 1080i and not 1080p.  Perhaps the DisplayPort can't do 1080i (update: I now know that it can do 1080i from the adjustments with the Monoprice DisplayPort->Component adapter) and can't do 720p either but only 480p or 1080p.  That seems very limited, but it would explain what I am now seeing.  I have turned off the kitchen TV but maybe I need to disconnect it from the HDMI splitter to get a higher resolution.  Anyway, I'm actually glad it does support 480p, which is more appropriate for some things.  But what I'd like to do is be able to switch among these resolutions (and even 1080i, if that is possible, to get best image on my kitchen TV).

Wednesday, November 28, 2012

More fun with Kenwood L-1000T

Just a few weeks ago I hooked up my Kenwood L-1000T (aka Kenwood in this post) to my whole house Sonos audio system using a Behringer DEQ 2496 digital equalizer to correct the European 50uS deemphasis to the USA 75uS standard.  In the digital domain I can do the conversion quite well, even with the limited choice of cutoff frequencies.  I use a 6dB per octave shelving at 2212Hz.  Right now I can't remember the dB of adjustment but I think it was between 2 and 3dB (calculated in an earlier post).

Well of course I couldn't even enjoy the Kenwood over Sonos without this change (or something having a similar effect, like actually changing the parts in the Kenwood), so even though I had hooked up the Kenwood to Sonos back in July, I hadn't really used it much for the Kenwood.

What I mostly use this for is listening to radio in the bedroom.  The bedroom currently does not have any tuners hooked up (though, ironically, I have the stack of second best tuners that the Kenwood defeated now resting in the bedroom because the computer room has been overstuffed with junk).

When I used the Sonos system to listen to FM, which wasn't that often, I usually listened to the Marantz 2130 in the kitchen as it has the correct EQ and actually sounds very nice.  Sonos lets me pipe a line-input signal from any room to any other room, it goes through a moderate quality 44.1Khz 16 bit uncompressed codec with digital level adjustment so you can optimize the dynamic range.

This was a revelation.  The Kenwood always sounded great, but now I could actually stand listening to it for hours, and using my KT-6040 remote control, I spent one evening scanning radio stations.

On Tuesday night I found how the Kenwood L-1000T with correct EQ really blows away the Marantz 2130 over Sonos.  The Marantz sounds veiled and muddy by comparison.  (It doesn't sound that way at all in the kitchen, possibly because of different room acoustics and near field listening, but also possibly this test is unfair, I have fully optimized the Sonos level for the Kenwood a few days ago, currently max tuner output gets to -3dB digital maximum, but the Marantz level in the Kitchen has not been optimized, and was about 20dB lower, causing huge loss of digital resolution (though I raised the volume level to compensate, it can't restore the resolution lost over 16bit depth conversion and transmission).  Possibly the Marantz level actually depends on the volume level I set on the amplifier in the kitchen, actually a Yahama receiver.

But I also came to notice on Tuesday night this week that the signal from San Antonio City College was mono.  I noticed this because I happened to pipe the Kenwood output to the kitchen system, and look at the stereo separation on the L-R scope mode of the Marantz.

So I took a careful look at the display of the Kenwood tuner.  It was showing only one (tiny) bar of signal strength, yet the RF selection was Direct.  Obviously this was causing a weak signal and limiting stereo separation.

For some time now, I had been convinced that the 6040 remote doesn't control the station control settings on the Kenwood.  But somehow I had pre-programmed Preset 2 for Direct mode.  Either I had actually set the Direct mode somehow, or at some earlier time the signal strength may have been stronger when I was setting the presets.

I was able to un-set the Direct mode by this procedure:

a) Disable setup mode using small button to the right of tuning knob.
b) Change the tuning by the minimum amount in either direction.
c) Change the tuning back to the correct center tune.

This forces the Kenwood to determine the best settings for this station, and when I do this now, it correctly choses High Sensitivity mode.

Now the fact that the presets had been programmed with direct mode suggests that possibly I had been able to control the RF mode previously, and I had deliberately chosen direct thinking it would give the best sound quality.  Or, more likely, I had set direct mode for KPAC, a much stronger station, and had failed to unset it for the remaining stations that I programmed.

Taking the remote in hand again, I struggled and with much fiddling with angle and direction was able to get the Kenwood to change RF mode once.  I think the capability is actually there, I just lost it when I stuffed the Kenwood into the corner it now occupies, which gives no good way to aim the remote at it (the Kenwood is immediately behind the transformer of my Acoustat speaker).  I can try to control it from the side that I have open and it sometimes works.  I can also use the Remote Extender system which I use to control the preset station selection from the bedroom.  That also has a receiver over the living room mantel so I can point the remote at that rather than at the tuner.  It works, mostly, for setting presets, but may not have enough IR resolution for the advanced settings like the RF mode.  The remote extender has a transmitter I place just to the side of the L-1000T and it works, at least it works well enough to change presets.

It may also be the batteries in the 6040 remote have gotten weak.

I need to experiment with this more, it was already well past my bedtime when I made the above discoveries, and I decided to stop because I know these kinds of explorations can last all night and typically end on some frustrating note.  But I will be back at it soon.

In the meantime, I used my mis-tuning method to get the Kenwood back to receiving the city college station in High Sensitivity mode.  But if I change the preset, this gets messed up, so I really have to find some way to fix it.  I could also memorize the preset with the High Sensitivity mode.  But I also forgot how to program presets, I alway find this confusing and counter-intuitive on Kenwood digital tuners and I need to read the instructions again.

But another flaw is that I can't, or at least was unable, set the IF bandwidth.  When I change the RF mode back to High Sensitivity using the method above, it also resets the IF bandwidth to Narrow.  It really doesn't need to do that I think, as Wide works fine on Direct mode, it should also work OK on Narrow.  But as yet I haven't figured out a way to change that.  Perhaps the remote will do this, and perhaps it won't.

Here's a discussion of HDMI/HDCP handshaking.

There are endless blogs of people describing issues and frustrations with Apple's Mini DisplayPort.  Many people have suffered with the disappointment that they cannot use their cherished display with their cherished Mac.  And for many of those people, the problem did not go away the next day.

After you look at the discussion of HDMI/HDCP handshaking, it's not surprising that this technology is so finnicky.  HDMI/HDCP want to make sure you're not doing anything that isn't allowed (recording!).  And it seems, even a slight seeming irregularity will shut them down.  Also, all HDMI/HDCP units have an internal state, which may need to be reset by powering down the unit for 10 seconds.  You try powering down everything, making all the connections, then powering up switches, then displays, then sources.  If that doesn't work, try powering down everything and then powering up switches, sources, and displays.  Some configurations work better with powering source first, others with powering display first.

Oh Boy.

Thursday, November 1, 2012

Playing with the Kurzweil

A month or so ago I pulled out my mint (barely used) Kurzweil K2661.  Over in the corner where it has had a nice custom made table to sit on for the last 4 years, it has mostly just sat, because it's just no fun to stand in that corner and play.  So I pulled it out right in front of the Queen Anne chair at the back of the living room.  That makes for a great place to play.  It is lined up with the L-R of the speakers.  Obviously one does not get the incredible image one gets up front.  But one does get a nice distant image that I find good enough, and the back of the room, and the Queen Anne chair, is much more suited to playing than in front.  And the beauty of this arrangement, with playing chair in the back and listening chair up front, is that both are independent and always available to be their best.  I can leave the Kurzweil out for the whole month until my end-of-the-month party, when I can temporarily put it back on the custom made table in the corner.  The rest of the time, it can be out in the room.

That's exactly what I did for the party in October, I put the Kurzweil away on the morning of the party and back after the party, so it was unavailable for the minimum time.  And when I set it up this time, I skipped all the wiring mistakes I made the first time, and got the wires entirely out-of-the-way instead of taking-up-the-whole-room.  There is one passage, around to the couch in back, that has become a bit tricky mainly because of the Kurzweil itself.  But now I make the front path to the couch around the listening chair entirely clear of wires.

Since I purchased the music workstation in 2006, I suspect I've used it less than 400 hours, mostly just random playing, barely learning how to program or do anything (though I know it's all can do anything, well almost, play all parts you've recorded at once, just like a full band, with accurate (to varying degrees) renditions of every kind of instrument or synthesizer, and every aspect of every Program (instrument) can be edited, or new ones can be created from factory samples or new loaded samples.  The Kurzweil gives you a nice collection of samples and raw sounds and an all-inclusive (just about) set of all the possible transforming operations that could be done with them, and then you can hookup as many of one to the other and to controllers in as many ways you can imagine in fairly long channels.  Thus, it makes you the instrument designer, and you can make it do anything anyhow.  It's a kind of soft instrument made of user programmable DSPs, which uses actual DSP hardware to realize how it is programmed.  A true analog instrument with as many capabilities as this would fill a building.  (DSP = Digital Signal Processors)

Last month I finally figured out Record Mode, or at least I recorded myself a few times, and it actually worked.  I've been watching the video tutorial that I downloaded from Kurzweil or somewhere when I bought my unit.  It's good, but it doesn't start with creating Programs and so even though I've now watched half of it I still haven't gotten to the programming part.  I watched him record a sequence, and after that I got it to work.

Here is one of the better tutorials I've seen on creating a Kurzweil Program.

Monday, July 16, 2012

Two Steps Forwards, One Backwards

After getting back home from a long Saturday (trip to nursury, dinner, concert) I thought I'd catch up on a few audio issues in the master bedroom.

Ever since I set up the Linn Sondek turntable system a few months back, I haven't had a 24 bit ADC to digitize the output of my Denon 3910 DVD-Audio/SACD player.  I moved the Behringer DEQ 2496 over next to the turntable to keep the analog lines short.  So I had to plug the 3910 straight into the Tact RCS 2.0 analog inputs, which are notoriously 16 bit (or at least 16 bit performance).  To add insult to injury, I also had to attenuate the DVD player output with a 6dB attenuator to be sure it did not overload the maximum 1.5V input of the Tact.  Actually, 3dB would have been sufficient, but when I set this up I had run out of 3dB attenuators.

To fix this, a few weeks back I have moved the MSB PAD-1 into the bedroom, but hadn't hooked it up.

Here's a list of things I ended up doing:

1) Removed Acurus L-10 preamp, now possibly not working (or at least LED not lighted).

2) Removed Yahama T-85 from underneath Tact.  The T-85 has issues and I haven't used it in several years.  It was finally convenient to remove the T-85 after I removed all the stuff on top of the Tact.

3) Vacuumed, vacuumed, vacuumed (top of Tact, MSB, Aragon and rack)

4) Hooked up the MSB, including its power adapter, and hook its AES/EBU output to the Tact (#5).

3) Moved the Aragon 28K preamp on top of the MSB.  It had been over near the phonograph system, but was not being used.  I had tried using it instead of the tube preamp for the Panasonic strain gauge cartridges, but it didn't work well in that application, nevertheless it had stayed there.

4) Hooked up the 28K to the analog output of the Denon.  Only the Denon is now hooked up.

5) Removed old analog line from TV to Acurus.  Apparently I had set up this line because the digital link from TV to Tact was once not working well.  I figured out why also (see below) and fixed it.  This line used a long interconnect, two 3dB adapters, and a Radio Shack isolation transformer.

6) Moved 30 foot Toslink connection from TV to Behringer used for phono system.

7) Extracted M-Audio CO2 from living room and connected to Tact with coax (finally using fancy radio shack coax, one from BJC was too stiff).  This adapter converts toslink to coax digital so I can use one of the 3 coax digital inputs on the Tact.

8) Tried BJC toslink from TV to CO2.  Very intermittent, usually not working unless I wiggled the cable at the input to CO2.  Now I remembered I had this problem before.

9) Extracted a 2nd 30ft toslink cable from behind the sofa in living room.  That second cable has been ambushed there by a snarl for several years.  Using that cable, the CO2 worked fine, so now the digital connection between TV and audio system works fine, and also allows remote switching to the digital connection between phonograph and audio system.  Previously I had to manually switch the one working 30 foot toslink cable I had between TV and phono system, which didn't encourage me to play more records.

10) Adjusted gain on 28K so that Denon would not clip MSB.  My first test was playing a Chesky jazz disc 'Havana' over and over and noting the peak level.  That was a very time consuming test, but the disc was already in the player.  Later I used the Stereophile test disc 2 on track 17 and noted the "average level".  Finally I used the 19+20K distortion test, turning off the DCX so as not to play through speakers.  With that test playing at 0dB, I had average level about -3.5dB with volume control at about 2:30.  Peak level was just above -20dB, but I don't think that is a problem.  I need to make a better test disc for this purpose.

11) Finding that I couldn't see the Denon on my TV, I reconnected the S-Video cable that goes through Isomax transformer.

12) I played a multichannel SACD and was finding that despite setting SACD control to stereo, the indicator still showed multichannel output.

13) Fiddling with the Denon setup menu, I found it was necessary to turn the Denon-link off in order to adjust the audio from multichannel to stereo.

14) I listened to several discs, notably Hanson conducts Hanson, as background music as I was working on stuff.

15) Once I got the TV working over the 2nd toslink cable, I ran that for several hours to make sure it was working without cutouts.  It was playing a Nova special on string theory.

16) Tested phono system which I haven't used for a couple months.  The Linn appears not to start.  The pushbutton light goes out quickly after the start button is pressed.

****  So I went to a lot of work to make it possible to switch digital inputs from TV to Turntable and back, and then guess what, the turntable stops working !!!

I may fiddle with the Linn a bit more.  Also this might be a good time to check out the Sony turntable.  I never actually inspected the Sony circuitry, I just disconnected it at the first sight of bad operation.

It's sad that my phono system isn't working again.  But it seems I like to play DVD-Audio and SACD discs more anyway.

Wednesday, June 27, 2012

Ground loop hum from HDMI even over CAT6

One reason I had been using a fiber optic connection between kitchen and living room was electrical isolation.  The fiber optic connection could not in any way create a ground loop.   I decided not to use another fiber optic system because it would have cost a minimum of $300 more than the CAT6 alternative, and possibly much more, and because the CAT6 connections are cheap enough I could extend them to even more rooms.

I was hoping that the CAT6 digital video balun, which transforms the HDMI transmission into one that goes over a pair of CAT-6 wires, and then back to HDMI, would not induce the ground loop, given that the two baluns would isolate the ground.

Unfortunately, it did not work that way.  Once I hooked up the new video connection system using CAT6 and baluns, I did get a slight amount of ground loop hum in the living room system, regardless of analog input chosen.  When I disconnected the RCA's from the TV, or disconnected the HDMI cable from the TV, it would go away.

So I went through my cable box and could not find any more Jensen Isomax CI2RR audio isolation transformers with RCA jacks.  I did have one spare unit last year, but I took it for the computer I use at work, which creates horrible hum because the computer is plugged into an online UPS but the amplifer isn't.  I had been using a cheap Radio Shack isolation transformer there, but apparently the current running through this ground circuit when the UPS is power the computer was great enough to burn out the Radio Shack unit.  So far the Jensen has not suffered the same fate.

So for the last week I had been using a spare Radio Shack isolation transformer.  It did the isolation job fine, though I wondered if it had the best audio fidelity.  (From measurements, I know it gets rather high bass distortion if level are high enough.  The Jensen is almost perfect, as it should be for about 10x the price of the Radio Shack unit.

So today I have ordered another CI2RR isolation transformer, along with an 18 inch DVI cable (for the HDMI audio inserter I use on my harddrive recorder which has no HDMI outputs), and a VS-1SS S-video isolation transformer I can use with the Denon 5900 in the living room I use for audio discs.  The living room TV has only one HDMI input, so normally it will be connected to my kitchen video hub.  On special occasions, I could hook the Denon to the TV using a DVI/HDMI connection, but it's not necessary normally because I can use the Oppo BDP-95 in the kitchen to watch video discs instead, and that will always run through the new CAT6 HDMI connection.  Full remote control of the Oppo works great too, through the Radio Shack Remote Wireless Extender transmitter I have in the living room.

Tuesday, June 12, 2012

Fun with FM and TV

I have been finding that my Kitchen system has more clarity on FM when playing in the "Direct Stereo" mode of my Yamaha receiver.  That mode bypasses analog-to-digital conversion, DSP processing for eq and crossover and surround, and digital-to-analog conversion.  I know that the Direct Stereo mode bypasses all this because I tested it many years ago.  It's quite clear when digital processing is being done, because square waves coming through the unit have that distinctive pre and post ringing at ultrasonic frequencies.

Well usually Direct Stereo sounds better, and I think it's mainly because of the crude crossover that is being used, that crosses over to subwoofer at 100Hz or 80Hz, most likely at 12db/octave.  In the bedroom, a larger room, I cross over the subwoofer at 48dB/octave at 60hz.

I had usually kept the receiver on "2 channel stereo" because, despite the name, that is the mode that uses DSP to implement the crossover for the subwoofer.  That still works best if the deep bass is the most important part of the sound.


I've also tried some surround options.  Concert Hall uses DSP processing to get a concert hall effect out of 5 (or 7) speakers playing plus subwoofer.  It makes the normal stereo seem a bit wider.  It has the most impressive effect on a mono announcer, he sounds like he is speaking from the stage in a big concert hall (duh).


Over the second weekend in May I finally got my living room TV hooked up again to my central video system (in Kitchen).  That means I watch satellite TV and hard drive recordings and and computer and DVD's and even Blu Ray discs from the living room TV.  That was what I had set up in mid 2009, but late in 2011 the OWLink optical transmitter for HDMI to the bedroom failed.  I replaced that transmitter with the one that had previously been used for the living room, and ever since then, there has been no video system connectivity to the living room.  (The bedroom is the most important video link, I use that connection daily.)  For showing my monthly movies in the living room, I've typically used the Denon 5900 player there, and fortunately all the movies I've shown since November have been brand new (no concern about dirt from rental movies).

As discussed in this blog, I investigated several options.  I could buy a new OWLink kit for about $450.  They are very very hard to find (out of production for several years) but can be found.  There were other optical options as low as $299.

I decided to try a CAT6 balun instead.  They are much more widely available and more reasonably priced, from many brands, and the connecting CAT6 wire is a commodity product which can be readily replaced or extended.  I got the basic kind that uses two CAT6 wires.  This has essentially the same number of wires as the HDMI cable itself, so the system is relatively low cost.  Much more expensive systems manage to cram all the information into a single CAT6.

Setup was actually quite easy.  The hardest part was running the two CAT6 wires, but even that was fairly quick.  I had bought the 50' CAT6 wires from two different Best Buy stores, but they worked fine together.  I also hooked everything up to make sure it worked before running the CAT6 cables behind the couch and under the kitchen counters.  That pre-testing made running the cables harder because the cable became a huge snarl rather than a small roll that could be simply unrolled.

Another trick was getting rid of the audio hum.  After the HDMI through balun from the kitchen was connected to the living room TV, the audio output goes into Analog 1 of the TACT preamp.  There was a bad hum after hooking up the HDMI because of ground difference in the two powerline circuits.  So I used a Radio Shack isolation transformer on the audio line, and it fixed the problem.  (Now if I could only get KPAC to fix their hum problem.)  I plan to replace the Radio Shack isolator with one from Jensen that I use in other locations.  The Jensen transformers are very good, but also this is only TV.  If this were a high resolution audio line, I'd figure out some other solution.  The main other solution would be going back to fiber optic  HDMI.  I was hoping I wouldn't have to do that, and it has turned out that I don't need to, but I did need to use an isolation transformer.

I also took the opportunity to add the DVI-plus-Audio--to--HDMI adapter to the DVI line from the Anchor Bay DVDO.  That means the audio signal is sent down the HDMI connections to living room and bedroom from the hard drive recorder.  I had been using that for several months now, but it got taken off during the massive rewiring on the previous weekend that moved DVDO and HDMI-switch into the main rack for reliable remote control from all rooms.

I also replaced the 15' HDMI cable (borrowed from the Mac-to-Bedroom-TV connection) with a new 12' HDMI from Blue Jeans cable.  That means I got the Mac-to-Bedroom-TV cable back, for use in the bedroom as intended.

The system currently lacks a "rental" dvd player because that unit, a Denon 2910, is still under the table where there is no no remote control (I've given up trying to get remote down there through wireless transmission, that was the whole point of the rearrangement) and no HDMI connection to the main switch.  Probably that player should be moved to the main rack also, so it can be controlled by remote.

Friday, June 8, 2012

Resolution needs more bits

Resolution is not "signal to noise ratio (SNR)."  Resolution refers to something we can't easily measure directly, but infer, in analog systems.  Analog amplifiers have the potential ability to reproduce every voltage level from zero to maximum, subject to limitations (noise, distortion, etc) which are additive in nature.  If the world were truly continuous, this would mean it can reproduce an infinite number of potential voltage levels, for in between each two levels we could specify, there would be another.

It is already known that we can hear a signal even when embedded in noise that is equally loud, so long as there is some other characteristic we can use to distinguish the signal from the noise, such as frequency response.  If the noise were pure gaussian, and the signal a pure tone, it is easy to see how this could also be done electronically as well as by ear.  I can't think of a general rule which would describe the limits of ability to do this.  For quite some time, it has been claimed that we can still hear the signal even if the noise is 15dB louder, but if our hearing were as good as possible for any acoustic sensor, and we had some pre-knowledge of either the signal or the noise, the noise could be much higher still relative to the signal.

Digital audio systems have been designed to have SNR nearly as good as the best possible analog equipment, and far better than most, with the potential 96dB SNR at 16 bits.  Perfectionists like me have sought to use 24 bit digital audio systems that have potential 144dB SNR, which is better than the best available analog amplifiers.  That has to be good enough, right?

Well, no, if the goal is to have the same resolution as analog systems.  I can't prove that we need this extra resolution, but I have some suspicions that it is, and I think it's interesting to think about what that kind of performance would require.

The answer seems to be we need bits to encode resolution down to some appropriate quantuum level.  Assuming the world is like that described by quantuum mechanics, 
quessing an appropriate quantuum level to be about 10^-33 volt, the number of bits required for 0-1V would be about 76 (2.3 bits per decimal digit x 33).

I can imagine a 24 bit encoder expanded to full 76 bit capacity.  Alternatively, and even given off-the-shelf parts, one could cascade multiple 24 bit encoders.  Suppose a successive approximation method is used, then we could simply make sure that 76 iterations of successive approximation are done.  Now we can't prove we have 76 bit accuracy, but I wasn't so much worried about accuracy as resolution.

Now such a digital encoder would probably not perform as well as an ordinary 24 bit one with regards to signal to noise ratio.  But often analog systems don't do that either.

I say not to worry about either the fact that SNR is not improving or even getting slightly worse.

Now I've only been considering the quantization accuracy here.  What if we consider time, making the sampling interval as small as possible.  Well, that gets us into trouble very quickly.  It is clear we have no hope of digitally encoding at something like a quantuum rate (10^-30 sec), and we would have no hope of storing so much data either.

My guess is that, for us, the amplitude accuracy is more important than the timing.  I've generally felt that 96Khz sampling rate is sufficient.  For what it's worth, audio research published in JAES has claimed that jitter, for example, isn't audible until we get to the 100's of nanoseconds, about 1000 times worse than the level modern digital equipment performs at. 

A 76bit/96Khz stereo datastream would require less than twice as much as a currently used 24bit/192Khz datastream.  It would be quite feasible to implement, if you were making digital converters anyway.  A major problem would be fighting off the nags who say it isn't necessary and has no proveable benefit.

Monday, May 21, 2012

Scoping the tuners

Marantz 2130 scope showing Kenwood L-1000T
Not long after I had the Kenwood L-1000T hooked up to my Sonos system, and was listening to it in the Kitchen (comparing it to the Marantz 2130 I just recently reinstalled in the kitchen) I decided I'd like to see the "Stereo" scope display of the Kenwood.  The Stereo display plots L vs R, so you see a diagonal line when there is mono, and something like a big fuzzy blob in stereo.  It's a visible measure of stereo separation.

So I hooked up the CD-R output of my Yamaha receiver to the scope inputs on the Marantz.  That lets me scope anything playing on my kitchen system, including the Marantz itself, using the EXT mode on the scope selector, but I can also view the Marantz itself using the Audio mode on the scope selector.

Marantz 2130 scope showing Marantz on EXT

It often seemed to me like the Kenwood might show less separation.  (Consider the pictures above for illustration only, they weren't taken simultaneously.)   The EXT Level controls on the Marantz scope are somewhat non-linear, but I adjusted the control so that the scope display looks mostly identical when switching between the EXT display when the Marantz itself is playing, and then to the AUDIO display which is showing the stereo display from the Marantz itself (not going through the Yamaha receiver).  I could get those two to look the same, but input from the Kenwood still looked different.

That is not how it sounds.  The Kenwood sounds like it has just as much separation, and has even more depth.  So is it that the Marantz is separating even what shouldn't be separated?  I'm thinking along those lines.

I believe the Sonos system is doing an accurate job of delivering the audio in 16 bits with no compression, which is how I have set it up (unless it got changed somehow).

Radio Palace

So I have the world's best tuner, Kenwood L-1000T, in my living room system.  I can simply play that system and hear it all through house.  It sounds sweet and transparent everywhere, often drawing me into the living room chair to listen more closely.

And I have Marantz 2130 scope tuner by my fingertips when seated at Kitchen table.  I can play that when I'm at the kitchen table when I haven't turned on the living room system first, or if I want to listen to something different.  An analog scope tuner like this invites you to explore the dial and find new stations.

What could be better?  Well on Monday I hooked the Kenwood variable output (buffered) into the input of the Sonos Zoneplayer in my Living Room.   Now I can play the Kenwood in Bedroom and Kitchen systems as well, connected through a 16-bit digital system.  It sounds nearly as good as in the living room.

Only a few minutes transpired after hooking up Sonos to hear the Kenwood from the bedroom before I also wanted the remote.  So I hooked up a Radio Shack remote extender in the living room, and pointed it right at the Kenwood.  Unlike many other negative experiences with these extenders, this time it worked perfectly right off, and I can use the KT-6040 remote to control the L-1000T perfectly from either the bedroom or the kitchen through the Remote Extender transmitters I have in those rooms.

Not many tuners have full function remotes.  Even though I don't have the correct remote, I can tune new stations in either the automatic or manual modes using the remote control, and memorize them.  Even the Yamaha TX-1000 only lets you select presets, and the Onkyo T-9090 MkII is the same.   I like the way the Kenwood clicks when tuning, has a vintage feel, but I worry if eventually some of the relays will wear out.

Tricks used in removing smell from Marantz 2130

Marantz 2130 reinstalled in Kitchen, now unlit dial
I finished the smell removal process and re-assembled my Marantz 2130 on Saturday night.  By 1am or so I had it set up again in the kitchen, and I played with it until 5am or so, listening to the usual 3 stations plus scanning the dial.  It really is fun to have an analog tuner with scope at one's fingertips, and I think this sounds better than a Kenwood KT-8300.  Which reminds me how way back in the early 1970's people would make fun of the TOTL Marantz tuners as being "Pioneer with a scope."  Well it wouldn't be far into the 1970's when "Pioneer with a scope" would more praise than put down.  Pioneer was known for making good sounding tuners, arguably the best sounding!  The 2130 does in fact sound a bit "Pioneer" to me, not unlike a Pioneer 9500 mkII.  Very dynamic, punchy, musical, open, but also quiet.
Cleaning inside the tuner with Q-tips and Alcohol
Probably the #1 trick in making the smell go away was removing the dial lights.  I was originally going to return the dial light circuit board after cleaning it, but then I noticed I had already cleaned the top pretty well, and the bottom was essentially clean.  So then I wondered, why did it make so much difference to the smell having the dial lights removed vs connected?  Well of course the dial lights generate a lot of heat, looks like 15W or so, nearly half the power consumed by the entire tuner.  That heat drives a lot of ventilation airflow through the tuner, ultimately ejecting hot air at the front edge of the top cover.  Plus, the interior of the tuner is directly heated by IR emissions from the dial light assembly, and gets much warmer.  So the dial lights are driving a process of vaporizing crud inside the tuner and conveying it to the outside, a worst-possible scenario for smell.

I'm guessing that 50-80% of the total progress I made in smell elimination (reduction, actually, but nearly elimination) was from removing the dial lights.  I'm not particularly bothered by the unlit dial, which can be easily read under room illumination.  Eventually, I'll devise a string of LED's for the dial light.  They won't get hot and won't cause the outgassing of smelly stuff.  Funny about the time this tuner was made other manufacturers went to unlit dials.  Famous tuners with unlit dials include the Pioneer F-26 and Yamaha CT-7000.

I'm suspicious that the Marantz repair center replaced all the dial bulbs with new standard replacement bulbs, but the 2130 possibly requires lower wattage bulbs.  I'm just guessing, I felt the dial was brighter than it should have been, but it didn't look washed out either.  The brighter dial was driving more release of smell.  The dial is mostly metal, only the numbers and indicator marks light up through hairline openings in the dial metal covered with blue plastic.  Seems like a waste that so little light should be produced outside when so much light was being created inside.

Now even after running the tuner for 18 hours at one time, I smell nothing right next to it, UNLESS I sniff right where the dial needle indicator light (still connected), jewel indicator lights (for FM and Wide Band), and Stereo light.  There, I can still smell a slight bit of the original smell.  I'm thinking I could make further progress by disconnecting those lights or converting them to LED's also.  Why should a light light up to show you have selected FM?  I've usually selected FM, the separate light for indicating AM is sufficient to know if I haven't.  For Wide Band, it would make more sense to have the light glow for narrow band, to remind me to turn it back to wide band.  In general, lights should indicate things you might want to change, temporary and possibly undesireable warnings rather than permanent situations.  That way, as an additional benefit, they can be off mostly.  My final idea along these lines: change the Stereo light to an "unStereo" light which only lights up when the stereo carrier is too weak to get stereo, or if you have mono selected.  Perhaps a special light for mono selection, once again to remind you to turn it off.  No lites on should mean optimal reception, nothing to think about.

Other things I did:

1) Washed top and bottom covers and faceplate and screws in soapy water and alcohol.  Placed outdoors on sunlit table in afternoon several times.

2) Put chassis on outdoor sunlit table on breezy day.  Turned upside, downside, front, and back.

3) Cleaned off chassis metal with cloths damped with water and Everclear.

4) Cleaned off chassis metal, plastic dial assembly, transformers, backside of two circuit boards facing up, gyro-touch knob and protective plates, and edges and corners of IF and other circuit boards with magic solvent.

"Magic solvent" is Everclear (95% ethanol) with with 1 drop per ounce Thieves' Oil (natural fragrant antifungal) and 1 drop per ounce DeOxit.  I'm not sure if the DeOxit does much good in this formula, it didn't intermingle.  The Thieve's oil is sufficiently light that you can't much smell it much directly, but it seems to cancel out the bad smell, and I think the bad smell may be partly fungal...a fungus eating on the cigarette smoke residue.  Anyway, the smell of Thieve's Oil is very pleasant, so it wouldn't bother me if I could smell it.

5) Removed dial light circuit board, clipping green wires that powered it, bending them so they won't contact anything.

6) Re-washed cover with magic solvent.

As an additional repair, I also put two wire ties from the retaining clip on the front end assembly cover, threaded through slots in the dial assembly.  This holds the wire for the needle indicator light, preventing it from falling on the IF circuit board.  I have previously used only one wire tire, switching to two wire ties seemed to make it a bit better, though still the wire can fall during certain tuning operations to be only 3/4 inch from the board (when I first got the tuner it would drag across the board while tuning), on average, it's mostly suspended by wire ties at the maximum height.

When I cleaned with simple water, I didn't see much coming off.  But q-tips dipped in the magic solvent would quickly get brown cleaning off chassis metal or the corners of circuit boards.  I used up about 100 Q tips.  The underside of the tuner did not get cleaned with magic solution, though I did use water and everclear on cloths on chassis metal.

Success!  The smell is barely detectable, even close up to the tuner after many hours of operation (and I think that's mostly because of the 4 still operating lamps).  And it still works, putting the cover back on has restored normal operation compared with the way it was 3 weeks ago when I first took the cover off.

The tuner runs much cooler without the dial lamps (as shown in picture at top).  The faceplate is ice cold, the cover merely only just noticeably warmer than not after 18 hours of operation.  I think I could put a Marantz wood case on the tuner now.  Previously I worried that a wood case would trap too much heat.  I have a Marantz wood case which might fit.

Tuesday, May 15, 2012


I have been greatly enjoying my Kenwood L-1000T.  On Thursday night I gave it a serious listen, and was blown away, listening in intense sessions until 6am.  It has transparent, sweet, beautiful, dynamic, punchy, musical sound, but also silence from noise.  No apparent information loss from dynamic limiting as with Sony XDR-F1HD.  Completely transparent from top to bottom, unlike Pioneer F-26 which seems a bit veiled at the very top.  Bass solid down to subsonic frequencies.  Nothing unpleasant about the sound at all, and I heard some of the most convincing cello I'd ever heard from any source component.

On Friday night, I continued listening, but discovered that it only sounded right either at a loud level, or a very soft one, with intermediate levels just sounding wrong.  I suspected that my unit did not have deemphasis for US standard of 75uS, but rather for European standard of 50uS.  On Saturday I removed the Kenwood from my system and put the Pioneer F-26 back online.  I was shocked at how much noisier it sounded, I had always thought the Pioneer was one of my most quiet tuners.

Taking the Kenwood apart, I confirmed it had the 0.0082uF capacitor, as required for Europe, and not the 0.012uF capacitor called for in USA.  This tuner is even more beautiful on the inside than the case with dark metal and cast sides.  The main circuit board shown above is large and appears to be made of high quality material and packed with parts, organized in sections.

The RF stage is in a large metal box on the right side, from initial appearances it looks as massive as the RF capacitors on earlier Kenwood high end models like KT-917.  Of course this one only uses varactors and isn't nearly as good, but the rest of this tuner is far far better, making up for somewhat pedestrian RF stage.  Though small the RF stage does use a good single amplifier in a well thought-out design.

Along the left side is a large power transformer, a power supply feature two large and prominently "Audio" labeled power capacitors, and a second switching power supply for the computerized electronics.

I decided it would not be easy either to solder on an additional cap, or remove and replace the cap (though that would be somewhat easier). I am thinking I will get an equipment modifier to make that and other changes for me.  You can see the two brown colored mylar capacitors in the close-up photo below.  All the parts on the circuit board have leads that penetrate holes the board, and are soldered on bottom.  I have dealt with such printed circuit boards before, but I generally find it tough when the parts are packed closely together, as they are on this board.  Boards with surface mount components are worse.  I like modifying point-to-point equipment the best.

The bottom side of the tuner showed no additional capacitors soldered onto the bottom, as is sometimes done for quick modifications. 

Meanwhile, I figured out how to compensate for the european EQ.  I set up a parametric shelving filter in my Behringer DCX 2496 crossover.  Somehow this seemed to work best when I set the F to 2210Hz, with High Pass, but the amplitude set to -2.6dB.  That rolls off the highs above 2210Hz to a maximum of 2.6dB, reaching that maximum around 3180Hz (where the 50uS EQ kicks in).   I set the 2.6dB by ear then determined it would be correct for the frequency range from 2210Hz to 3180Hz, allowing for 6dB per octave slope.

The resulting sound was both superb and accurate.  A friend remarked it was both sweet and clear, my thoughts exactly.

I like having my top tuner play in the Living Room.  I can hear it pretty well in the rest of the house while I am doing things.  I often like background music, though perhaps even more often I like to have it off.  With a good tuner, I like to keep the music on more than with a lousy tuner, it seems.  But when I am playing background music with the L-1000T, it often draws me into the hot seat to hear it up close as well.

When I go into other rooms, but have FM playing in the living room, I obviously don't hear the stereo separation as well, though I hear much about the fundamental tone.  But often the reduced impact from lost separation is just the ticket to free my mind from the need to listen.  If I had the FM playing in each and every room, it might be too much, I'd want to turn it off more often, just to hear myself think.  I'm still working through these ideas.  I have so many tuners, the thought of having a tuner in every room appeals to me, then I could listen with full separation in every room, and also full local control.  But also simply to listen to background music from the living room tuner works mostly also.  I could also distribute music from the living room tuner to the rest of the house using Sonos, and use remote control in any room to change the station.

Thursday, May 10, 2012

Yet Another List of Good Stuff

I stumbled upon this list of recommended components by Chuck Hawks.  Very interesting because he doesn't get into audiophile catfights (in contrast to Type A Audiophiles).  I think (and hope to discuss further soon) that is the correct approach.  When you reach a certain level of quality, our audio knowledge isn't certain enough to be negative on anything, especially since such negativity feeds the Audiophilia Nervosa syndrome monster that afflicts many serious audiophiles.  Someone might well choose not to have a Mark Levinson preamp, for example (there's a long standing audiophile legend which is probably myth that the ML 38 and it's successors are dark sounding) but it's really not fair to  say a guy who likes it has a tin ear, because by objectivist audio engineering standards there's nothing wrong with it.

It looks like a pretty good list for what it includes, through lots of good brands are not even mentioned.  He confesses he is only discussing equipment he is personally familiar with, so it obviously can't be complete.  At the same time, certain brands get blanket recommendations in multiple categories, like Accuphase.  I would agree that you can't go wrong with Accuphase amplifiers, preamps, and tuners, the company created has always refused to make anything but top quality pieces, none of which would be totally out of place in a reference system even today, but has he really tried them all?

In full range speakers, I don't see Revel, Acoustat, Sound Labs, Magnepan, Dynaudio, or many others I'd mention.  Note he does mention the nearly unobtanium KLH 9.

The tuner listing is the best, because the number of super tuners is actually a bit limited, though even there he omits tube-era-Fisher, Scott and Sansui and only one Pioneer is listed.  I don't think I'd include the second tier Marantz like 2120 and ST-5.  Most interesting he does not include Marantz 10B (one suspects he has heard some samples, given the rest of his encyclopedic experience, especially with Marantz tuners, so this omission is an implicit damning) or the 120 (considered a known dog now, though possibly they were better when new and could be rehabilitated by someone who really understands ceramic filters).

Thursday, May 3, 2012

Showdown at the Perfect Polarity Pundit Corral

Above is a picture of a copy of my official Polarity Test 2012 disc (having only the 20 minutes of positive polarity pulses) played back on an Adcom CD player in default polarity mode.  Despite claims by my longtime friend George S. Louis, the Perfect Polarity Pundit, that the Adcom GCD-575 and the NEC CD-730 have opposite output polarity in their respective default normal polarity modes, results identical to the above were obtained in all the tests I performed on Wednesday and Thursday on both players.  And despite his claims that the EZDup Cool Copy CD-6198 inverts audio polarity in copied discs at 16x, in our test on Wednesday night, the copied disc also showed identical results.

The display program was SignalScope Pro demo version (I have mixed feelings about this product, but the polarity test I created was deliberately created to work even with scopes that don't trigger well) running on a 13" Macbook Pro.

We also used the polarity test track on the CBS Test Disc CD-1 and found that the first pulse was positive, and the second pulse negative, on both players in their default polarity modes.  George and others had claimed that the CBS Test Disc was recorded with a negative pulse first.  Presented with this information, Stan Ricker later claimed the intial disc was incorrect but that CBS corrected the disc in later production.  We also made a copy of that disc on the EZDup, and we agreed that it showed the correct polarity on the Adcom and NEC players.  The pulse on the CBS test disc is extremely hard to use.  The track lasts 60 seconds and has merely one up pulse (at 17 seconds in) and one down pulse near the end.   Often, the pulse occurred in the interval between one scan and the next.  But we did these tests over and over until we saw at least one of the two pulses, and on most of the critical tests we repeated the track until we had seen both pulses.

Thanks to George who let me run these tests on his equipment and publish the results, even if they appear contrary to his claims.  He says he only seeks the truth by any and all means.

In the past few years, George, aka the Perfect Polarity Pundit, has generated a lot of online text and emails for his polarity obsession.  He claims to have found that lots of CD players and digital audio recordings themselves vary with respect to a relatively well understood factor known as audio polarity.  Any given audio system can reproduce sound either with correct or incorrect polarity as compared with the original sound.  Correct polarity is generally worth preserving, it is well known that humans can detect the effect of incorrect polarity in at least some simplified and extreme cases according to research published by leading audio scientists in the Journal of the Audio Engineering Society.  But that same published research suggests that polarity is not generally audible over loudspeakers (it's most audible with headphones) and not generally audible with musical content having more than a few instruments playing.  George, on the other hand, believes polarity to be among the most important factors in audio reproduction, and furthermore, that it is often reproduced incorrectly due to widespread polarity errors in CD playback devices, CD duplicators, and recordings themselves.  Many audiophiles have come to believe the same thing, either because of independent discovery or George's influence through his website, emails, and personal interactions with leading figures in audio.  Most of George's polarity testing has involved some kind of listening test, ears and brain being required to perform the test, though he claims some of the tests are essentially objective anyway.  I have disputed the objectivity and reliability of his polarity test methods, and have called for what I consider objective tests using unambiguous test signals and an oscilloscope.

Confronted with scope images like the above, which have so far showed no variation among several component level CD players he claimed had different output polarity, and no changes caused by CD duplication, George says he can't explain my results, and criticizes me for having a closed mind in this regard.  I do indeed see these results as being hard proof that the Adcom and NEC (and, in previous test Oppo BDP-95) players have identical polarity, and that George's finding them as having different polarity was incorrect.  And that the EZDup Cool Copy does not invert audio polarity.  George believes many if not most digital CDR duplicators invert audio polarity based on his results.  I find that idea laughable.  But he has to continue to believe that to support his whole edifice of sighted testing and  anecdotal evidence.  If particular CD duplicators do not invert as he has claimed, many of his findings would no longer fit his polarity story.

Further he claims that the mere fact that I have not yet found a polarity difference among all the players I have tested so far (7 or so, including several George believed to have different polarity) is evidence my methods may not be fully reliable.  [Update: As of Saturday night, we have now found two Memorex portable CD players that do invert audio polarity on all tests.  I have never claimed that all CD players, especially cheap portable CD players, are correct.  A few years ago I found an iPod music player to have incorrect output polarity using an earlier louder version of my test signal and a scope.]

George has years of anecdotal evidence (which he is constantly recounting) and listening tests supporting his views on the polarity of the Adcom and NEC players and many others, as well as the polarity inversion caused by the EZDup and other duplicators.  Not surprisingly even faced with exacting measurements which show the opposite, he is not (yet) willing to change his views.

Also, George has one measurement device which has often, it seems, agreed with his polarity calls.  That is the Galaxy Audio Cricket-R.  The Cricket creates a chirpy electronic pulse in it's line output which it can also read back (either through line input or microphone) to determine speaker polarity.  George has recorded a long duration of Cricket pulses on a CDR to test CD players.  He connects the output of the CD player to a line input he has created on the Cricket by plugging a XLR to RCA adapter into the Cricket XLR microphone input.  It then may show either a green light indicating correct polarity (no inversion), red indicating incorrect polarity, or neither light.  During our use of this device, the "neither light" condition seemed to be the most common.  Faced with neither light lighting up, or a light not as George expected, he would twist the gain control until it showed the light he expected.  On several occasions, it could show a red light at one gain setting, and a green light at another.

I'm not exactly sure how the Cricket works, but even from our limited use of this device on Wednesday night, I would not consider it to be 100% consistent.  If it can be used to obtained different results than my series of positive pulses viewed on an oscilloscope, it is entirely clear to me that it is because the Cricket is inconsistent.  I suspect it was not designed to test CD players.  As it uses a low frequency pulse, it is possible that variations in low frequency response may be the cause of inconsistent results.  I suspect it has been designed to work well with testing speakers but not electronic products like CD players.  It may be confused by the extended low frequency response that CD players have compared with most speakers.  Here is what the Cricket electronic chirp looks like:

But George remains puzzled.  He never stops thinking or arguing how his polarity calls must be correct, implying my tests must be wrong, but he won't say that my tests must be wrong, he just doesn't know.  He cannot believe the Cricket would show incorrect results, especially when those results are consistent with his listening tests.  He continued arguing with me about these results continually from Wednesday until Saturday night, when after some tests on a second polarity inverting Memorex portable player I told him I did not want to hear any more of it.