Kitchen Audio UPS Reconsidered

Back around 2008-2010, I purchased 3 Belkin AVU1500 audio power conditioners with UPS.  Originally priced at $1500, these were being closed out and discounted to $350-$500.  There appeared to be nothing like it on the market, and Monster Power made conditioners that didn't look as beefy for the price and lacked UPS.  I reviewed and photographed the internals of the Belkin units on this blog.

Even then, I knew that the UPS part of the Belkin was probably not particularly good, though it has massive battery capacity and you wouldn't think it would be that bad either.  But I knew at the time I bought these units that Belkin had dropped out of the UPS market and was then only selling power conditioners for audio.  That was not a good sign, and I had the fear that the UPS was not as good as it should have been.  Since then even the name Belkin seems less heard then before.  Not to be confused with the leading US cable manufacturer Belden, for which it always seemed Chinese Belkin was a ripoff name.  I always knew that, but Belkin made neat looking stuff I could just buy rather than reels of cable, and I didn't look past them just because of the name.  In stores such as Computer City which no longer exists, the Belkin cables were the priciest you could buy there and didn't look bad while everything else looked like freebie wire.  I never had a problem with Belkin computer cables, but haven't needed any for 15 years since SCSI and Parallel cables went out of fashion.  Since that time over a decade ago, I have gotten most of my audio  and video cables from Blue Jeans Cable who uses genuine Belden wire.  Only once ever did I get Belkin audio cables and while they seemed to have the right stuff (polyethylene dielectric for example) I didn't like them much because of the too-tight connectors.  I may still be using some Belkin speaker wire, looked similar to Monster zip cord with polyethylene dielectric.

It also appeared that the UPS section of the unit was not given that much attention in my earlier investigations.  But I was then leaning heavily on the power conditioning aspect as being the more important one, and at least the power conditioning parts inside the Belkin looked serious.

The three units I purchased were intended for living room main system, kitchen system (which is also my "Audio/Video Production Center", and the Laboratory (previously called the Computer Room).

Since then, the Laboratory hasn't been cleaned up enough to do much work in there, let alone set up the Belkin UPS.  So the unit designated for the Laboratory has been sitting around unboxed in various rooms, first the master bedroom, then my climate controlled storage building (dubbed Lyndhurst).  It was one of the earliest pieces moved to Lyndhurst and was sitting on the bottom of a pile that reached to the 9 foot ceiling.

The Belkin UPS in the living room has done well.  Actually I think that was the second one I purchased.  The power conditioning has always seemed adequate, it looks the part, and the UPS has almost always kept the digital equipment running continuously so I don't need to reset stuff all the time.  It started beeping about batteries in 2013 and got a new set of batteries then and has had no issues since.

The UPS in the Kitchen had been doing fine until 2014.  Then it started beeping too, and it got a new set of batteries.  Those batteries lasted only 19 months until now.

That didn't seem right.  Batteries lasting only 19 months isn't normal, UPS batteries should traditionally last 3-5 years and in low impact use can last up to 7 years.

Replacing the batteries in the Kitchen UPS is a task that takes at least a dedicated weekend if not two.  A gazillion wires and several pieces of key equipment need to be moved out of the way just to pull the UPS away from the wall so that I can remove the battery "cartridge."  Then the cartridge itself must be disassembled and the batteries packed in a box to take down to the battery store.  Then after getting the new batteries, everything has to be put back into place.

A new set of batteries isn't cheap either.  The last set I purchased in 2014 was nearly $200 and prices seem to have gone up a bit since then.  The Belkin takes 4 batteries which cost upwards of $40 apiece.

It immediately occurred to me I probably didn't want to chance another set of batteries in the kitchen UPS.  I think there's a big chance the Belkin UPS isn't keeping batteries in good condition.  Perhaps the charger isn't charging up to voltage, or goes overvoltage, or something.  I never trusted the Belkin UPS very much, and wrt the kitchen UPS whose batteries failed in 19 months, I have even less trust.

So, I got out the unused Belkin sitting in the bottom of a pile of junk in my junk building.  That's what I did last Sunday.  I hooked it up for the 12 hour "charging."  Just to see what was happening I also connected a Kill A Watt meter.

I was shocked to see that it was only drawing 0.09 amp, or 1 watt.  I tried multiple times to turn the unit on by pressing the On button for up to 30 seconds.  It did not come on.

I left it plugged in for over 24 hours, then tried unplugging and replugging a few times.  Nothing.  It never draws more than 1 watt or allows itself to be turned on.

I took apart the battery compartment and examined the batteries and battery connections.  Everything looked perfect.  I measued a combined voltage of 5V.

I think what might be occurring here is that the 5V isn't enough to power some part which must be powered in order even to turn the "charger" on.  So it never even starts charging, there's a relay or transistor controlled by battery voltage that doesn't engage.

But the only way to know is--to buy a new set of batteries.  And even then it might have the problem of the old Kitchen UPS--the battery might not stay in condition.  And what happens after a deep deep discharge?

For the approximate $200 price of the set of batteries, I could buy a new UPS.  A real UPS made by a respectable UPS company, not a company that exited the business 6 years ago.  A brand new UPS that hasn't been subjected to 6 years of noisy AC power and outages and electrical work, not to menton loads such as my Sony 34XBR960 CRT television (now sadly deceased and removed).  I could even spend much less, only $139, and get a highly regarded very popular and top rated Cyberpower UPS with 1500 VA.

I also started re-thinking the kitchen UPS responsibilities.  This kitchen UPS isn't only for the audio system.  I can loose far more than not-having-to reset all the digital devices after an outage.  Here are the things the Kitchen UPS must keep powered:

1) The irreplaceable nothing-made-like-it-since Pioneer DVR LX70 video recorder which I have constantly playing programs in infinite loops to keep my bedroom TV busy.  A power outage could cause loss of the hard drive causing months of agonizing repair or replacement, not to mention lost programs, many of which have not already been written to DVDR's because that takes lots of time to do it well.

2) My Mac Mini, fully loaded with 1+TB hybrid drive.  This has all my music and video collections, as well as all my open applications, etc.  I do back this up,  at least, but losing it would cause a month of downtime.

3) My Dish Network DVR, with all my most recently saved TV shows going back months.

4) My HDMI 4x4 switcher (this could go down, but up-and-down probably isn't good, and like the Pioneer this is a rarest-of-the-rare unit).  My Oppo.  My DVDO format converter.  My Plextor Premium CDR drive.  Lots of valueable equipment I don't want to stress.

5) The managed Ethernet Switch for the entire house.  All the HDMI to CAT6 converters.

6) My security cameras, and the security DVR.

Clearly the UPS function here should be taken seriously.  It can kind-of be laughed off in the Living Room, but in the Kitchen I have a serious Data, Networking and Security center.

Meanwhile, I don't really know how important the "Power Conditioning" function is.  Objectivist audiophiles claim that the AC power purity obsession is unwarranted.  I certainly have no blind test results proving different.  In my attempts at doing objective measurements on AC power noise (using the Audioquest Noise Sniffer), I hadn't even found a consistent difference with the massive Belkin in place.  The only thing I've found to make a consistent difference in AC noise levels is having dedicated power lines, as I now have in the bedroom and living room but not in the kitchen.

Nevertheless, I did look for UPS's which claimed to have AC line EMI/RFI filtration, FWIW.

How I decided on a particular new UPS will be discussed in the next posting.

Shortwave Radio

It's hard to use Shortwave Radio unless you have some idea where the stations are.  The short wave bands are filled with noises that on a quick scan almost seem like they might be stations, and you have to pass over dozens of those before you get your first voice station.

Here's by far the best index of shortwave broadcasts, updated constantly to reflect what's live right now.

Shortwave is the most free broadcast radio there is, at least in most parts of the world.  In the USA all shortwave stations must get a FCC license and build a qualified station (typical cost of around $1M) but that's peanuts compared to what it takes to buy a slot on the FM dial.

FM, of course, is priceless but sadly most FM stations don't live up to the potential of the medium.

The Pioneer DVR-LX 70

Blogger Citibear gives us the essential service information here.  He describes the Pioneer DVR-LX70 as "priceless" and it is.  It is the best consumer Standard Definition video recorder/editor/storage unit ever made.  And it even has HDMI output.

As I've said elsewhere, I'm into Standard Definition Video Recorders for one essential reason.  This is the only video we are allowed to edit, copy and compile in any convenient way.  High Definition video recorders are essentially unobtanium in the USA both because of our onerous copyright laws and the unwillingness of manufacturers to push the limits as they were in previous decades.  High definition video theoretically can be edited on extremely complicated and buggy computer programs. I've basically had my fill of those (Nero, Roxio Toast, etc).  So many times endless hours of pushing stuff around to get the programs to make a nearly decent recording has only produced duds.  Standalone video recorders are far easier to master, easier to use, most often much faster to use, and almost always produce perfect discs.  And mostly fun, rather than mostly frustrating, to use.

Old DVR's are also much more fun.  They can be controlled with a simple push-button device that doesn't require you to look at it or use two hands.  It's called a Remote Control.  It's trivially easy to select such options as slow motion (often available in multiple speeds), reverse motion, endless pause, and so on.  This is power and freedom not generally available, or much more clumsy to use, than computer video programs.

It's also worth repeating, though it seems like ancient history now, that when properly displayed (as hardly anyone bothers to do anymore) Standard Definition is not only good enough (as it was for, um, 60 years) but can actually be very beautiful.  Ultra High Definition programs and displays tend to emphasize useless "detail" above beauty and accuracy.  And the added information is actually a bit illusory.  High Definition digital systems fundamentally rely on lossy compression.

But for the above mentioned reasons, those of us who would like to hold on to freedom and beauty are now forced to live like Cubans in Cuba used to: caring for and servicing our old hardware with no end in sight, and finding ways to continue despite lack of corporate support.

But I can't complain too much.  When I was a 30-something recording (and editing!) videos on my SuperBeta 900 I could hardly imagine a device as nice to use as the DVR-LX70.  Living in the post Standard Definition era, we can pick from the best of the best.  As long as we can keep it working.  And DVR's tend to quit working much more quickly than the best old time VCR's.  I last used my SuperBeta 900 just 3-4 years ago, and it still worked perfectly.  Meanwhile my first DVR, a Sony also with the 900 model number, died twice.  First the hard drive failed.  That's relatively easy to fix.  Then the DVD recorder failed.  That's very very difficult to fix since you have to modify a generic DVD drive to make it work, the special model 900 DVD part is beyond unobtanium.  So I just used the 900 DVD recorder as a hard drive recorder for awhile.  But now it's been replaced by my first LX-70, and I have a second LX-70 on order for backup.  I can't imagine getting along without one.

Last year I discovered the Magnavox units, still being sold new (I think) such as the MDR-557.  I have two MDR's, but they don't hold a candle to the LX-70 (other than that the Magnavox units do have a Digital TV tuner which is required now to receive OTA broadcasts and essential if you want to do "time shifting" of OTA broadcasts.  But that's not something I need to do.  I use my Satellite DVR for time shifting.

Not long ago I discovered the LX-70 can record on Dual Layer DVD's.  That means you can make two hour long compilations at the highest quality level.  Longer compilations are essential to get the most convenient use of videos stored on a hard drive on a standalone hard drive recorder, for many reasons, including that it's painfully hard to select from hundreds of video titles.  Scrolling through them is rather slow on the Magnavox, somewhat faster on the Pioneer.  So I create two hour compilations on the Pioneer and then store them on the Magnavox for background video.  The longer the compilation the fewer you have to scroll through to get to the one you want.

I play videos like most people (and me) play background music.  I select the two hour video I want and then do Repeat Title.  I keep the annoying audio track off and listen to music instead.

Speaking of which, I think "serious" audiophiles dismiss "background music" too easily.  I probably get most of my musical enjoyment, not to mention listening time, in the "background."  Now it's true, just like reading books, "serious" listening is a good thing which should be done as frequently as possible.  But time has to be set aside for that.

The LX-70 can not only repeat titles, you can create playlists of titles and repeat those.  That's also what I like to do with music.

What if Audio were like Video

In several ways I am grateful that audio has moved in a different way since the 1960's than video.  I credit the subjectivist audio movement, pioneered by the likes of J Gordon Holt and Harry Pearson, for getting audio off the corporatist objectivist track.

Now, mind you, there was much more progress possible in video than audio.  I'm not questioning that.  The video displays of the 1960's were pathetic compared to what we have now.  (Though not perhaps so much as people imagine at the high end.  Professional video displays of the 1960's were beautiful, and by the early 1990's they were glorious.)

Nor am I questioning that most subjectivist advice is pure crap.

But when the corporatists take over as they have in video, here's how things go:

1) Endless planned obsolescence.  Just as with computers and smart phones, the moment you buy anything it is already obsolete.  Endless upgrades are not only made desirable, they become mandatory.  If you haven't upgraded every 2 years you are way behind.

2) Facts are marshaled to show how much things are better, even when actually they aren't better at all.

3) Bigger is always better.  More is always better.  Bombasticity is better than realism.

Now the underlying story is that digital systems and endlessly refined display technologies have made fantastic possibilities in resolution upgrades.  Old Standard Definition video was (quite!) adequate for telling stories, and most of the greatest TV programs ever produced were produced in Standard Definition, now also known as 480i.  Viewed on well performing equipment (which is always rare in consumer grade equipment) those programs still look beautiful and tell stories very well.

Strangely, as soon as higher resolution became possible it became hard to achieve the same quality in story telling.  Resolution itself became the story, and people were wowed by so-called Reality TV with little story or human meaning behind it.

Now it becomes clear, just as the cynics said, we don't actually "need" resolution as high as is now possible.  Diminishing returns set in quickly as you go above 480i.  1080i is really, truly, about as good as we'll ever need for frontal displays, but now resolution has become the game and we're up to 4k displays with no end in sight.  1080p is gravy.

We also don't "need" wall sized displays in most cases.  Especially if we don't have mega mansion homes.  If we are living in smaller homes, less than 2000 sq ft, as most people should be since larger than that is wasteful, there simply isn't enough space for super large displays in most if not all rooms.

That is one of the things I find especially frustrating--that if you buy anything less than a 55 inch monitor you are assumed to be fine with second class.  Not just in the endlessly ballyhooed but relatively unimportant "resolution" game.  But in the far more important blackness level and color accuracy game.

In that game, btw, we are still behind the best CRT's of the 1990's and 2000's, including my ultimate Top of the Line Sony 34XBR960, the best consumer CRT television ever made.  LED color gamuts have been limited, they were ridiculously limited at first, even now with quantum dot technology they are only catching up.  But even that doesn't matter if the display can't render true black.  True black is the secret behind truly saturated colors.  If you can't do true black, you really aren't there.  And ordinary LED's, even after 15 years up you-must-get-this upgrades, still aren't.

Only one kind of LED can potentially get there, and that is OLED.  I'm glad to see that LG is pushing OLED technology onto large screens with 55" and 65" displays.  But what about for us people who can't deal with a display larger than 40" ???

Sadly, my 34XBR960, which does 480i to 1080i native scanning, so you can watch SD to HD without artifacts, failed on Monday and I hope to get it fixed.  (One tech said, you can buy a new 32" TV for $200 so why worry?)

This TV sits about 5 feet from where I sit at the kitchen table, giving the equivalent of a much larger display at 10 feet.  40 inches is about all the display I could possibly fit in between the speakers, which are already beginning to encroach on essential living space.

The Most Important Adjustment

Speaker positioning is generally the most important adjustment that can be made to a hifi system.  Listening position is important too, actually both are important together, but there are more aspects to the speaker positioning.  One of those aspects is the speaker angle, and this is super important when you have electrostatic speakers, because their sound is enormously affected by the speaker angle

At my first ever listening party for the River City Audio Society, I got only one negative comment: the system sounding harsh.  I admitted there was some truth to that, and in fact it was in mind when I switched to the Krell.  The harshness went away.  Usually.  Not always.  It has also always seemed to be very listening position dependent.  I aimed the direct beam of the speakers to converge just behind my head.  If someone sits too far back (as the commenting person was) they sit in the direct beam, which sound harsh or peaky or something.  This sometimes happens to me also when I don't check the chair before sitting down.  It seems to migrate slowly away from the speakers over days of time, and often need to be put back in place.

I've been thinking about other things also, such as the piles of electronic equipment behind each speaker.  I decided that had to go back about eight months ago, and planned to buy a new rack in August.  Right then, other things came up needing to be replaced.  Now I'm putting new rack (to be positioned on the side of the room behind the equipment) back on the calendar and I hope to buy it in January.  There's also the not-so-little issue of making room for it by moving stuff around in the living room that needs to be done first, and I'm thinking it might be good also to replace the windows, because once the rack is set up that's going to be a monumental task.  That could push the new rack beyond January.  And so it goes.

But meanwhile there's no excuse not to re-examine the speaker angle, which is just what I started doing last weekend.  Just on a whim, actually (that's often how great things start), I rotated the speakers as shown above from a looking down view.  I rotated the beam of the speaker further away from the listening position so that now convergence only occurs about 7 feet further back, near the end of the room.

This changed the highs dramatically and for the better I thought.  Just before this change I was noting that the singing on Supertramp's Crime of the Century was more than a bit twisted, it was all scrunched up.  With the new angle, the singers sounded much more like real, if unshaven, people.  Overall this was the finest audition of this recording I've ever had, and I've been listening to it on many fine systems including a friends Quad ESL system in 1979.

But how can this be, I wondered.  On typical box speakers, the beam of the speaker generally provides the flattest response, and many box speakers begin to have serious tonal irregularities off the beam, such as collapsing upper midrange, not to mention loss of highs which is almost universal.  And then, compared to box speakers, electrostatics are said to be even more beamy.

But this simplifies the actual situation greatly.  And there is even a never stated truth for electrostatics: straight on the beam they sound horrible.  This is puzzling for a speakers whose very design seems to eliminate distortion everywhere on the membrane.

But there it is.  Something is definitely wrong on the beam, I determined the next day.  I played the Stereophile pink noise track on repeat, attenuated the left channel by 99.9dB on the Tact "Level" adjustment, and used various iPhone apps, the cheaper one called Analyzer providing an RTA and generator only seemed to give the best pictures.

On the beam, I saw rising response above 4k and very jagged and generally rising up to my super tweeter at 18k, which had a large peak I tamped down by 5 dB right then...though there's still a peak it's not out of line with the 20-20k peak and on this app even shows tiny rolloff just at 20k.

I tried many different angles, ultimately putting down yardsticks to get some idea of the angles involved.  Right about 1' from the center of the front base, and 5 inches over, the response is much better.  It's at this point it might have maximal flat extension, but still jagged, and still a rise from 4k on up.  That's about the angle I used to be on.  At 7 inches over, the rise at 4k is pretty well tamped down, and further over it becomes a broad dip instead, with the highs generally rolled off.  Curiously some people might like the sound as far off the beam as 50 degrees best of all.   From about 60 degrees on around, you have a very depressed but perfectly smooth highs.  There's sound even on the edge of the speaker just like that.

My thinking was that 30 degrees nows looks just right, I'm currently at 22 or so--which was a huge improvement over the 10 degrees or less I was at originally.  No wonder I had issues with harshness!  6k-10k, the so-called harshness region of hearing, was strongly elevated.  I'm not thinking 30 degrees looks best of all, and coincidentally that will give me "zero toe in" relative to the room itself, with the speakers being parallel to the front and back walls.

Which makes me wonder if electrostatic speakers don't have some serious HF resonance issues, but helpfully those resonances are very directional, making it possible to escape from them by being off the beam.  I had heard the need to be off the beam from a long time Quad owner, so I figure this is not an Acoustat only issue.

Here's an article on measuring speaker polar response.

Sigfried Linkwitz has a different idea.  He says that the on-axis response of loudspeakers should not be flat.  This is because they are normally oriented about 30 degrees from our head axis, where we are too sensitive to sounds around 4kHz.  He recommends shelving the response (though in this blurb, the amount he recommends is unclear).  His Orion speaker is designed to be dipolar like my electrostats.

Here's a critical discussion of Linkwitz' shelving idea.  Critics maintain his shelving only compensates for something, either an inherent boost due to speaker width, or it compensates for other changes in the design which added a boost.  But it also reveals (as Linkwitz himself doesn't, at least at the link above, unless you buy the speakers) exactly what the shelving needs to be.  It is said to be a -3.2dB shelf at about 4kHz.  There must be less than 0.5dB of loss at 2kHz for it not to sound too soft.

It could very well be that the peaking I measure above 4kHz is a reflection or beaming type issue.  And it could be that the best solution might combine off-axis speaker orientation (relative to listener) and a bit of electronic EQ.

It's worthwhile taking a look at the measured quasi-anechoic frequency response of the Quad ESL-63, a speaker I continue to admire (and have often wished I had) as measured by John Atkinson in 1989.  Scroll down to figure 7.  Notice that there is a general tendency toward rolloff starting just at 4kHz (call Sigfried!) which heavily notches out 5kHz and just barely returns to baseline around 6kHz.  By 9kHz another steep dip is starting, reaching minimum just below 10khz.  Then there is peaking in the 11-14kHz region.  It almost looks as though the design is intended to suppress a resonance around 12khz with general rolloff.

I did not do quasi-anechoic measurement, but my near field measurement doesn't show as much rolloff at 16 Khz (highest pure tone I can still hear) until I'm about 50 degrees off axis.

All this suggests to me that it's OK to be pretty far off the beam with Acoustat 1+1's, unlike Quads.

NOSDAC: Cult or Cure ?

It was a very nice audio listening session.  The first ever where I'd invited audiophiles from the audio society to enter my main listening room and hear the magic.  All were favorably impressed, more or less, it seemed.  (You can never axiomatically interpret something like this, as if the system is Really Bad, you may not get any bad comments either.  It may only be where people actually feel threatened as you're nearing the pearly gates, but differently, and that can't be right.  So as they say among academics, the smaller the differences the greater the arguments.)

So from the most sage, the actual engineer with decades of professional experience actually making recordings, I got mostly (and actually somewhat surprising) approval.  What I had feared getting gored, the panel-to-subwoofer mating, as just got a not-so-quick touch-up days earlier, was pretty much accepted as successful.  But it was the panel sourced highs that got the barb.  "Harsh" or something like that was the word.  Despite all the praise, "I couldn't live with it" was the emphasis, which seemed out of place among all the other comments.

OK, I conceded.  I have indeed been aware of it and always struggle with it.  I deal with it mostly by moving my head into or out of the very central beam of the electrostatics.  You have to be sufficiently forward of the central beam of the electrostatics to get the smoothest highs, otherwise it sounds brittle.  Others later testified to what I described.  This near field speaker issue is real and needs further investigation.  I strongly believe this is the primary source of harshness in my system.  Later listeners confirmed the improvement from having head forward of the beam, and the criticality of this.

I didn't mention, but it may be clear to readers of this online diary, that much of my effort of the past 4 years has gone to addressing the harshness issue.  I recently bemoaned my trek in this direction as a loss to the then-alleged more important work of getting the bass decent.  But then I did some bass decency work just-in-time for the listening party.  But the kinds of things I've done were exactly replacing the Behringer DCX outputs, which aren't much praised by anyone (though objectophiles might say they were perfectly fine, having distortions well below audibility) with using a DEQ to drive an external DAC, currently the Audio GD DAC 19 which had inspired the engineer himself to obtain and now use the Audio GD Master 7.  Along with that change, the gain structure of my whole system changed, and now I run very close to 0dB with no attenuation, digital or otherwise, to compromise the resolution.  (I previously often ran with attenuation around 20dB, and despite my defending this with the claim that I have 24 bit resolution, I know it was suboptimal.)  So I've made major changes that I think can be defended on multiple objective grounds in attempts to eliminate the harshness, and they've been greatly beneficial.  Also, just using the Krell amplifier as compared to others I have, has a huge positive effect.

But my most sagacious guest had other ideas and didn't seem much interested in exploring the speaker/listener alignment possibilities during the listening session itself (though in much later comments, after the lamp had mysteriously become broken after someone tried to turn the lights off, he mentioned that speaker and listener orientation would be on the top of his list if I let him fine tune my system for a week).

Instead, he stepped into the measurements vs listening morass, and singled out the Krell amplifier as a potential part of the problem, effectively because of focus on achieving good measurements, and how many have moved to SET amplifiers, despite horrible measurements.

I look at the Krell FPB 300 as something very different from an amplifier designed to get "good measurements."  The very way it works is something very special in my view, with the output stage operating without loop feedback.  I believe this design is ideally suited for large electrostatics because it rejects electrical back EMF from the speaker, decoupling that from the actual amplification.

An amplifier designed simply to get "good measurements" could be made and used at far less cost than the Krell.

I have long experience with the Krell and a few other amplifiers, mostly the Aragon 8008 BB another very fine amplifier, I believe.  What amazes me is how much better the Krell sounds, and I believe this is precisely because of the special design of the Krell FPB, which isn't found on most other amplifiers, even Class A amplifiers, even most Krell amplifiers.  When I read about FPB amplifiers, the 300 and the 600, I just knew they were the ticket for electrostatic speakers which require vast VA swings, but accept vast EMF back from the speaker without compromising the signal integrity.  And everything in my experience has confirmed this.  They are the magic ticket for Acoustats anyway.  Now this is my experience, and my technical understanding, even if not acceptable to objectophiles.

Simply claiming that one might like the Krell because of good measurements demeaning.  That doesn't do justice to my sense about the Krell.  Actually, I suspect in a number of ways the Krell isn't the best measuring, and maybe not as good measuring as I would like.  If the amplifier has had to thermal limit down to the second stage of Class A operation, which is common, then peaks much above 100W are going to be increasingly distorted.  It is possible to get measurably significant distortion out of a Krell if one knows about how it works and can give it the right tests to show its weaknesses.

WRT SET's, I've never heard one that I liked, and have especially noted harsh sounding SETs at audio shows, sometimes besides very sweet sounding push pull tube amps.  There is every reason to believe that the high measured distortion is real and ultimately can do no good as it inter modulates with itself.  Many if not nearly all PhD audio scientists kind reject them (as do ALL objectophiles...no contest for them...and amplifier with 10% distortion cannot possibly be virtuous, and there is certainly no measurable advantage in distortion at low levels, as might be claimed).  Most of my long time audiophile associates reject them too.

Would I call SET a cult?  Yes, although remarkably widespread.  The audio science behind SET is remarkably thin but the sound is preferred by many thousands of listeners.  I think in most cases the deficiencies only become overwhelming at loud levels because of the companion cult to super-high-efficiency speakers.  In this case we are not talking so much about claimed-to-be audible differences. SET's sound different, no question about that, can be easily distinguished from low distortion amplifiers once the SET's are operating with levels of distortion well above 1%.  You may well claim there is a difference, though, in SET Superiority.  SET cultists, of course, believe in the SET Superiority, which comes from the virtue of simplicity.  They can "hear" that among all the other qualities and limitations of real SET amplifiers, which they may admit to.  Yes it's harsh when cranked up, but played softly it has intimacy or whatever.

And along a similar vein, the sagacious advice was that I must try (and would likely love) the No Oversampling (NOS?  didn't that mean New Old Stock or do we just distinguish these things on context?) option of my Audio GD DAC.

My mind waffles about whether I should even try this.  If I call SET a Cult, then beyond any question NOSDAC is a Cult.  It's far smaller group of people who use this kind of DAC (though interestingly, a group that highly overlaps SET and especially openness-to-SET as could be assessed by including those who formerly-used-SET), the backing among objectophiles and PhD audio scientists equally or even more thin, etc.

Strangely, then, one advantage that NOSDAC has is a more technically defensible argument, one that can be shown With Measurements (ironically).  NOSDAC's preserve the timing information.   They are technically perfect with regards to timing.  You can just look at the oscilloscope photos.  All the pre-ringing, post-ringing, and similar effects go away.  Now, finally, what you see "looks" exactly like, or the closest visible approximation to, the signal going in.  (Apparently the timing aspect is a key part of the visible picture.)

The problem is that technically perfect timing is obscured by enormous mass of audible distortion.  Unlike SET's which may be sufficiently undistorted at low levels to actually suit many people by objectophile standards, NOSDAC's distort horribly at every amplitude level, in every way, etc.  It turns out those apparently small "visible" differences are actually huge, we don't judge amplitude distortion well on visible graphs of square waves.

And what do I mean horrible?  Like, say, 30% THD.

That number 30% I am taking from PeterSt, Netherlands based senior member of ComputerAudiophile, in this long threat started by NOSDAC'ers   He seems knowledgeable and respected.  He was once a NOSDAC owner, started to investigate how it worked, began to realize it was a horror, then devised his own minimum phase DAC based on 16x oversampling.

The ever reliable Archimago has an exploration of NOSDAC's with actual graphs from a forward thinking DAC by TEAC with multiple options, one of them being NOSDAC.http://archimago.blogspot.com/2013/06/measurements-digital-filters-and.html

I might point out that many cult (and otherwise) respectable DAC designers, such as King Wa at Audio GD, prefer their own default oversampling settings.  That's where he put a lot of his intellectual energy, into getting right as-close-as-possible digital interpolation and filtering.  He also wants to show you what he has achieved by giving you the other options as well.  And it seems like many try the settings and end right back at King Wa's default.

Not to say that there aren't NOSDAC designers, in which category I would include Audio Note, who love their NOSDAC's.  This category has many cult famous companies, Metrum comes to mind, but by far Audio Note is the largest.  But of DAC designers overall, these are a tiny proportion.  In fact NOSDAC designers are what you might call anti-designers.  They "design" the oversampling by simply not including it.  And usually (following Audio Note) not including the filter either.  That's it, design over.  You don't have to be a very technical designer to be like that.  You don't have to have a PhD or even know math or audio science or anything at all.  You simply have to have a lot of Chutzpah, and if you know anything about the subject generally, combined with intense contrarianism.  But what if you had, one day, tried making a NOSDAC, and, voila, it sounded good by Listening?

So here we are back to the sagacious question: Listening vs Measurements.  Though perhaps my dislike for this drafting of the dichotomy comes from many particular issues with measurement per se.  By definition, a set of measurements cannot be complete, it's only a set.  There are infinite possible measurements, performed in infinitely many ways, as well as facing infinite inherent measuring limitations.  In audio, measurements have been fantastically exaggerated (such as Instantaneous Peak Power, occurring the moment the unit instantaneously self-destructs with man-made lightning), specified with incredible accuracy, or rounded up to nice numbers just to look like you don't care.  The best audio measurements usually come expressed by graphs rather than numbers, and the output of RAA is very nice, but still far from complete, and what manufacturer has given anything like the output of RAA?

You see the word Listening is being used here as if it The Ultimate Answer (because in a way, it must be), and Measurement as the thing we know which is often somewhat incomplete or misleading (and we have loads of other experiences with that in our expending enterprises), in a way to color this as if you must be a fool not to do what the questioner begs: "listen for yourself."

With a similar misdirection, I could redraft the question as Guessing vs Sound Engineering Principles.

While a seemingly simple argument can be made for the notion that you should just "listen for yourself" (and be fooled too, I would add) there are many fundamental problems with it as a tool of audio design and/or selection.  To wit:

1) Potentially biased (most likely, I would say, without thorough DBT)
2) Subject to future change (including the very next time)

Because of 1 and 2, the results of any one listening test have to be held in complete contempt, as not even having enough wrongness to be wrong, without either additional thorough testing (pref DBT), or reasonable objective story to back them up.

Further, the big problem with bias is that it feeds on itself.  Once you have developed the bias, it then becomes part of a very powerful bias to stick with it.

Now until researching this post I hadn't realized that NOSDAC's have a duller sound with proportionately less high frequencies.  I had known they produce more distortion, from aliasing, but had wrongly figured that distortion to add to HF making the sound brighter.  Instead what happens is the audible distortion is in the form of products which appear throughout the audio band giving it a kind of richness, not brightness per se.

So now that I know this, I could use the duller highs of a NOSDAC to balance out what may be the excessive brightness of the Acoustats.  I'm not sure if it would work like that, but it might seem to help in this way.  I'm tempted to try this simply for this reason.

But crucially any such "help" is truly a band-aid.  It wouldn't fix the underlying problem(s) whatever they are, just by adding a companion kind of distortion to cover up the original problem.

Certainly a better approach would be that rather than covering up problems, they should be sought out, and engineered out directly.

Of all the band-aid approaches, using something like NOSDAC to cancel out problems is the worst approach.  It's generally adding heaps of distortion, unrelated to the original signal altogether.  It's far worse than other band-aid approaches like using EQ to ameliorate room nodes.  Of course EQ isn't solving the actual problem (which is reflections in a bounded space), but it is using a linear means (which isn't itself non-linear distortion, nor produce more additional downstream non-linear products) to cancel out a major linear chunk of the original problem, and it is doing that directly by directly addressing the actual room mode frequencies.

Probably my NOSDAC loving friend would agree that NOSDAC's shouldn't be used as a palliative either, but rather that the problem is made to sound worse by being layered with the time distortions caused by oversampling.  If NOSDAC works as advocates claim, it should be used with the best systems as well as the worst, making the best systems even better.

And at this point, we can imagine a world of existing audio systems, many sounding fantastically good, and almost all of them, probably 99% or higher, NOT using NOSDAC's.  Ordinary OSDACs must be pretty good if they are used in most of the best audio systems.

Unless all the OS DAC designers, virtually all academic audio scientists, and most system designers are wrong, there is not really any need to even try NOSDACs.  For most people, this is simply a waste of time.  There isn't enough evidence to think this is a worthwhile change.  Everyone doesn't need to try everything for themselves, especially when the results of listening tests done improperly, as most are, can be confounding and create superstitions.

If we did want to verify NOSDAC claims of the importance of audible distortions, we could devise a number of possible blind tests.  One is a simple bypass test.

I haven't done this test, but I find it very hard to believe that the NOSDAC path would sound more like the original overall than the OSDAC.  In my imagination, the NOSDAC sounds somewhat different, whereas the OSDAC sounds about the same.  This would conform to the most important (if imperfect) set of tests done on digital audio by Meyer and Moran.  Listeners could not reliably hear the effect of digital encoding and decoding added to an audio path, even when done ten times.

The only way this imaginary bypass test could be claimed as a win by NOSDAC folks would be the claim that it maintains something special, amidst all the other clearly audible differences, a claim that would not be very credible.

While what one does with audio reproduction for personal enjoyment is a personal matter, I continue to believe that listeners are best served by the most accurate reproduction.  Harry Pearson called such a thing The Absolute Sound, and I believe in that, though not perhaps in his methods for gauging and approaching it.

Accurate reproduction is the goal of virtually all of the audio press, the audio engineering establishment, academic audio scientists, and so on.

There is a major dispute between subjectophiles and objectophiles, or black hats and white hats in Peter Aczel's terminology (himself being a self described white hat, John Atkinson being a self described grey hat) on the essential methods of achieving accurate reproduction.

Sighted listening tests are the standard of subjectophiles, double blind tests and in some cases just measurements are the methodologies of objectophiles, with subjectophiles often claiming measurements are unimportant.

My belief is not in measurements, which are incomplete and tentative, but in principles, when you can find them.  And the question doesn't come down to listening or not but to something more fundamental: how do you assess truth?

Is it really necessary to tour Auschwitz to know that the holocaust happened?  I think not, and in fact some denialists have toured such places only to bolster their opinions.

Truth in our experience comes not so much from direct observation as received wisdom.  In most cases, it isn't necessary to go beyond that.

Exploring the edges, where contrarians lurk, can be an honorable activity, but it is not something everyone need do.

Now this is not to say that in all our interactions with people and objects we are constantly assessing truth in various ways.  But most of these assessments are based on thinking and reasoning about known (or presumed) facts.  Not on direct observations.

Even our direct observations aren't really observations.  As much as science knows about perception, it knows it to be a largely constructive process, that builds models, often first, then tests them against the experience, or constructs them based on a perceived reaction to experience.

So there is actually no "need" to do listening tests at all.  It is generally a good idea to do listening tests on speakers, but largely I have purchased most of the speakers I own on pure speculation, without an opportunity to pre-listen (and such pre-listening tests, as at dealers, I'm not sure how much validity I would attach to, the best testing is always in-home testing, which is also the most difficult and most rare).  And I think I've done pretty well, with the Revel M20's, Acoustat 1+1's, and Gallo A'Diva's I own.  The speakers I have in my now unused pile wasn't all that bad either.  Given that I've been in this game for 47 years, it's not surprising I have a large collection of what I might now consider mistakes, though I'd try to rationalize them as stepping stones.

One merely needs to find the experts, or the ideas, one actually believes in.  Most of this is not a process of direct observation, it is a process of reasoning.  At best it is a measuring of other's consistencies.  At worst it is an assessment of other's tribe.  I fear I may not be doing the best always.

But that's ultimately what it comes down to.  I believe generally in what the majority of academic audio scientists believe, roughly the mainstream of the editorial staff of the Journal of the Audio Engineering Society, who won't accept subjective testing only double blind in most cases.

That means, I'm likely to find little or no merit in NOSDAC's.  Even if they initially sound pleasant, or uniquely satisfied, I'd still rationalize that as a euphonic quality I'd ultimately get tired of.

I believe if ultimately NOSDAC's actually are the way to go (which is entirely contrary to the way things look now), eventually this will be discovered, and pretty much everyone will switch to them.  There is no essential need for me to be on the cutting edge of such new things.  Not if I don't want to. Not if I think it's going to be useless.

Ultimately I don't think it's worth doing most audio listening tests.  There are infinitely many subjectophile "tweaks" one could try to make better sound.  There are endless cables one could try, and cable stands, cable separators, and on and on.  There's no respectable evidence (JAES is the standard, or the objectophiles at Hydrogen Audio) that such things make any difference.  As such, the best that could be reasonably believed about them is that they make small improvements.  How many small improvements does one need to bother with?

Exactly none by some accounts.  All by others.  I apply a little attention to everything, with more hoping to focus on the most important than doing so.  I excuse myself: this is my playtime, I'm just trying to have fun, and the important work has more difficult and boring parts.  And realistically there are indeed problems with exploring the most important kind of changes (or perfections!): loudspeakers.

One should always go after the biggest possible improvements, or at least the low hanging fruit.  In almost all audio systems, that means the loudspeakers (and the room, EQ, absorbers, etc).  Very little attention need be paid to the electronics and uncompressed digital sources because they are already very highly perfected.  And I do hew to that at least some of the time.  I pretty much ignore audiophile tweaks except as fashion accessories--I like them for that.

If loudspeakers are the biggest factor, as objectophiles and I believe, loudspeakers should be what almost all of our tests are about.

But what about the recording engineer?  It is commonplace that even experts aren't experts about anything in their own precise field, let alone others.  It seems to me he has keener observation about many things than most, but that does not prove his all his observations, ideas, or beliefs are correct when I find others with ideas I find more believable.

Given what I am, I can't simply accept any expert's opinion exactly.  And I believe that even many people with good powers of observation and refined expertise can still be profoundly wrong about some if not many things.

So I decide which ideas of which experts to accept, and which to reject.

How do I do this?  Mostly by my own reason.  Very little based on my own observations, but I have performed DBT's on myself and others, and that experience continuously shapes my ideas.  Most subjectivists haven't done such things, no matter how many sighted tests they have performed.  Basically what even the most minimal participation in DBT shows is that hearing is unbelievably biased and unreliable at qualitative testing, and audiophiles can't prove they hear the things they claim to. This is because we've evolved to correlate, to ferret out connections even if we get a lot of false ones, not comparators that can reliably compare things over time, and time is the ether of sound.

Even for audiophiles the ultimate sense isn't hearing, it's thinking, and especially determining what to believe and what is important.  And examining the thinking of others is not a distraction, it may be the best place to start.

System tuning requires iterative process

For several years now, I had not used my GenRad Oscillator because I thought it was broken.  I finally got around to removing the MDA 0.25A fuses, and found they measured about 5 ohms.  Then I looked up the cold resistance for such fuses, and it's rated as 9 ohms.  So by the book these fuses could still be good.  I put them back into the oscillator, and, It Worked!  Sometimes things are just like that.

This is the kind of oscillator best used for speaker system tuning because it has a big full turning logarithmic frequency control which sweeps the decade 20Hz-200Hz, and going a bit lower than 20Hz actually.  So it's easy to do useful frequency sweeps at any speed, and the resolution is immense.  I have other oscillators, such as a B&K with a linear control, and it's nearly useless for speaker tuning.

Now I had really intended to do measurements, and possibly parametric EQ calculations, by Room Eq Wizard.  I did my first measurements with REW in January this year.  And I haven't done any since, because there is some complication in setting up the computer, interface, microphone, and stand.  And it could be argued that is far better than my very old fashioned approach of sweeping an oscillator by hand and adjusting EQ's to fit by ear.

But just because I got the oscillator working, which was a little miracle, I went ahead and checked out the oscillator.  I wasn't planning to spend a whole day, just a few minutes.  But I ended up only finishing the tunings (they're only finished when you can write them down and get them recorded and measured without being forced, simply forced by one's own ego, to change them again) about 20 hours later, with 8 hours sleep and breakfast in the middle.  Now in the process, I did listen to a lot of music also, which then sometimes motivated me to make more changes.

So like I said, many times, including after the first hour or so, I tried to write down the adjustments, and move on.  But just going over them, I couldn't leave them alone.  I couldn't believe they were done correctly, I must have been mistaking the Q as I often do, not fully remembering the correspondences to bandwidths.

So that's how it went, just changing them, sometimes just because I thought they must be wrong.  Often making the changes, at first, or in the middle, I didn't bother to verify.  But then towards the end it became clear that verifying is the key step.  And not just at any one frequency, but sweeping up and down at various speeds.  And that's because the correction process is far more complex than you might think.  It's far more complex than most automatic systems can actually handle.

That's because the speaker and room system has a lot of possible states.  And those states, the position of compressions and rarefactions in the air at any one time, and the positions of everything in the room, and so on, are very very complex, even if ultimately "linear" it is far more complex than any single set of measurements can reveal, and more complex than a single deconvolution can address.  (And the simplification in most FFT's of what is going on in the bass...is nearly absurd.  You absolutely cannot do a tuning based on 1/6 octave FFT, though that can be an additional useful test and verification.  But imagine a problem with 10,000 variables, and you're modeling it with 30.)

It's very much like this, you have a particular peak, so you make an exactly equivalent notch to notch it out.  But it doesn't notch it out.  You're left with at least half as much as you started with, most likely, and possibly slightly shifted in frequency and q, or split into two separate frequencies and Q's.

So the only way a correction can be done is iteratively, not just in the mathematics but in the measurements.  You make one measurement, do one set of fixes, make another measurement, make another set of fixes to the fixes, and so on.

Since automatic systems generally just do one measurement and pray for the best, they can't possibly be as good as obsessive kid with his oscillator, sweeping up and down until all the bumps are gone, at least if he had infinite time.

Unfortunately, I was so unsystematic in everything, I can't assuredly say that my work here is truly great, though it's a vast improvement over the way things were before.  I really should do R.E.W measurements along with the oscillator sweeps, and so on.  But for now I am going to let it go, because I've already invested too much time in this for now, and it's actually pretty good too.  FWIW, here's the smoothed 1/6 octave measurements from Analyzer app on my iPhone:

That might look rough, for one you can only blame me for about 120 Hz and below, and it was far rougher as well as more complex at first.  The flat shelf from about 40Hz to 100Hz would be several huge peaks, falling off at the bottom for no good reason, and hugely bulging at 100Hz to sound like mid fi.

In the process of doing this, I discovered that my disc players, not often used, had channels reversed.  I think you can't blame the audiophile with so many different things that can go wrong, and constantly experimenting, for getting lots of things wrong.

Oscillator system tunings, November 2015

Panels

LR24 at 80Hz using two 2nd order Q.707 filters in combination

Right Only, 120 Hz, 1/2 octave, -4dB

Subs

Right

32Hz +1.0dB Q2.8

40Hz -4dB Q6.3

45Hz -6.4dB Q4.5

57Hz -3dB Q4.5

69Hz -3.5dB Q7.9

96Hz -8.4dB Q6.3

Left

32Hz +1.5dB Q3.2

40Hz -7dB Q7.9

46Hz -9dB Q4.0

51Hz -4dB Q7.0

71Hz -8dB Q7.1

LR48 (oops!?  I thought I changed that to LR24 to be symmetrical with panels)

-10.6dB (both)

Super Tweeters

Set down 6dB after monumental bulge on iPhone analyzer, still about 4dB bulge, believed correct for wider dispersion pattern in random noise.