Living Room System

Wednesday, July 1, 2015

The Warning Label

Warning!  This product makes explicit or implicit claims regarding auditory performance which have not been verified by published Double Blind Testing.

So we can just slap this label on high end gear, and the DBT evangelicals should shut up.

Just in case you haven't heard the argument.  There are 4 kinds of deficiencies in playback that we can hear: noise, distortion, changes in timing, and changes in frequency response.  Those are the only things that have been established to be audible, and only within certain measurable limits.

My version of the high end pursuit goes beyond the "established audible" and tries to make things as good as reasonably possible, combined with perhaps some additional parameters, my favorite being "information" given that we have lossy systems and systems like DSD and Delta Sigma Dacs that I believe are lossy.

I believe indeed many things have been overplayed, my key one is jitter, whose established audible limits are far beyond the level audiophiles obsess about.  Overobsession with jitter leads to paranoid avoidance of digital signal transmission via SPDIF which is what we have.  I do as much transmission and processing as I can in the digital domain, because it is measurably far superior, and sounds transparent to me.  At the end of the crossover lines, I (will) have nice DACs that drive amplifiers via decent cables and that is pretty much all (I like blue jeans BJC-1 design…it even satisfies my tweako itches with a solid core center conductor and polyethylene dielectric, not to mention the low capacitance and double shielding.)  So that gets to another thing for many audiophiles: cables, often at increasing stratospherically increasing multiples of the cost of a Blue Jeans Cable, and most often inferior in many ways, supposedly sold on "listening" but as much as anything it's all cultism, hero worship, tribal identification, and so on.

I am convinced that PCM is fine, and nothing wrong with high rez PCM.  I also believe that transistors are fine and tubes are most often used as a flavoring device--which may significantly reduce transparency.  I don't find the need for much flavoring, and transparency is the thing to me.

Digital is fine, but analog well done is also fine, and often seems more pleasurable.  I don't understand this though I theorize about it a lot.

Meanwhile, I do see much of the high end audio scene as a circus medicine show.  But I also think it should be patently obvious that it is so.  Need not argue with the clowns.  Pointless anyway and generates bad feelings.  Meanwhile, I follow my own magic practice to which the High End Warning nearly equally applies.

Sadly none of my audiophile friends wants to accept the key finding of DBT, that things are very hard to hear reliably.  Their magic practice depends on the belief that they have discovered many important things, important to them, by (non-DBT) listening tests.

I have rarely even attempted DBT, but I have the additional view that because sighted tests often lead to superstitions that don't hold up to DBT, listening tests beyond the basic may not be worth doing.  I haven't even much "tried to hear the difference between DAC's" except at clubs and friends houses.  I follow my casual listening result, just plugging new things in and assessing sighted difference over time, knowing that it too may be wrong, but not much different than "careful" sighted A/B testing.  But measurements of certain kinds are, in my belief, still useful, so I have them too, and thinking about how things work.

Here's one of the more amusing (and less bitter) confrontations between audio objectivists and subjectivists.

I've been discussing ABX hardware (not so much the Big Debate) just a bit on my computer club blog (which I am nominally "President" of).  I've been taking apart a QSC ABX box.  The account was not renewed by the actual owner and the email list turned defunct.  Conicidence?

I wouldn't think of mentioning anything about the ABX comparator or DBT at the Audiophile club I am a member of.  If it comes up I try not to say much or anything.

It is an in-your-face thing.  To suggest that people are all wrong.  But the sad thing is, most audiophiles are wrong, almost all in fact.  Even very smart people, Especially perhaps very smart people.  But best not to make a big deal about this.  The minimum one's conscience will let one get away with will do.  Let the rich sheep get slaughtered by the fraud.

I'm only "right" because I have a very nuanced leopard spotted view.  (I like leopard spotted better than grey hat, what John Atkinson claimed to be when confronted with Peter Aczel's White Hat (Objectivist) vs Black Hat (Subjectivist) dichotomy.

No actually I don't claim to be uniquely right, but I think overall I'm on a better track, and I do work constantly on improving mistakes, updating my views.

Having one's own ABX facilities is a bit like having one's own casino.  Want to try your luck?  I think it's a very cool feature for an audio system to have.  And it does actually require greater precision in fine level adjustment than most people are used to.

Tuesday, June 30, 2015

Shielded Box for line level signals

Bud seems to make more insulated alloy boxes than Hammond.  Mu Metal is a trademarked name, but many companies make similar alloys which combine EMF and RFI shielding.

Anyway, my current plan is to adjust levels digitally upon switching amps, therefore no need for attenuation in line.  But ultimately a Bud box may serve as the Y-adapter for the signal to both amplifiers even if there is no attenuation.  And the box may switch the signal from one box to the other to minimize loading.  And it may have an optional attenuator.  It may even have switching relay inside.

Why not modded DCX's ? Why not miniDSP ?

Instead of getting DEQ units for each range of digital crossover I need, another alternative is to get a DCX with a modification to permit digital outputs for each range.

Unfortunately there are not many companies offering this mod (and in fact the company that did appear to offer this mod according to old posts in various places does not list it on the company website anymore).  The last time I saw this mod listed, they wanted $999 just for the modification, or $1299 for a modified unit.  Since the price of a new DEQ in the US is now $299, the modification price equals 3 brand new DEQ's, and the cost for a fully modified DCX with 3 digital outputs equals 4 brand new DEQ's.

To add to the uncertainty, the only picture shown for the modification only shows high and low pass outputs, with the mid connector marked N/C.

And then it's a modification by technicians of unknown skill, compared to a brand new factory made unit with warranty.

And having the 3 DEQ's means that you can have meters or spectrum on each one, which is cool.  Though perhaps it's not so cool to have a pile of three units when one would do the same job.

Also, the DEQ's have AES/EBU output and Toslink output running in parallel, whereas the modified DCX's only have coax spdif.

On the other hand, the downsides that have appeared with the DEQ are:

1) Space, takes more space
2) Reliability?  I've had two DEQ's fail since 2005 but not one DCX fail since 2008.
3) Balance only to about nearest 0.2-0.3dB
4) Level only to 0.5dB
5) It takes some calculation and testing to set up a 24LR crossover.
6) You are limited to 6dB, 12 and 24 LR, and a few other crossover choices.  Notably you can't do 48LR because that would require making two 4 pole Butterworth filters.
7) Less convenient to mute.

Fortunately, delay is settable (though the delay menu is hard to find).

I'm still planning to go ahead with DEQ's for each crossover range.

An entirely different option would be to use miniDSP's.  They would cost more than the DEQ's and I'd still need one per range, they require a computer to set up (the DEQ can be set up entirely from front panel controls), I'd have to learn how to do what I want, and there's no "meter" option.

I still like things I can control directly without having to plug in a computer.

Monday, June 29, 2015

The Power Box

Cullen Cables makes a relatively inexpensive 6 outlet power box that I might get for my amplifiers.  This design would let me plug in up to 3 Insteon on/off modules to turn amplifiers and/or trigger supplies on/off.  I've also been looking at flat rack mount boxes by Tripplite that feature built-in ammeter, however those flat strips aren't friendly to the Insteon modules which would have to be plugged in through stub cords as I am doing now.

My dream version would have two wires wrapped around the hot inlet capturing info for a remote ammeter.

I came across this looking for serious upgrades to Sonos.  Over the weekend I enabled my 6th Sonos Connect, for the Turntable/Tape/Masterlink pod in the master bedroom.  This new Connect lets me more conveniently play turntable or tape throughout the house, and without going through multiple preamps that used to be required so it sounds better.  Plus it will allow me to record FM without worrying about what I last listened to on the main bedroom Sonos Connect.  It will also make it more convenient to monitor digital levels.

But as good as the Sonos connection just sounds now (listening to tape on the living room system was mind blowing…about as good as it gets…despite going through so many things) I wonder about upgrading the analog inputs I use ubiquitously.  Modifiers seem much more interested in modifying the analog outs which I don't even use, and the clocks which I think make little difference.  Unfortunately the old Cullen Circuits mod (now available through Wyred4Sound) is mainly a clock/dac/analog-out upgrade, and its key feature is up sampling (something I don't want).

The balancing act continues

I've found I can balance both main power amplifiers pretty close to the 0.1dB spec simply by using the Behringer DEQ 2496 image "tilt" control.  My current adjustment is 1 degree Left for the Krell, and 0 degrees for the Aragon (the Aragon already now being balanced to .15dB or better).

So then level matching the two amps comes down to level, and my current level setting is +1dB for the Aragon.  That's as good as I can do through the DEQ because now I find out it can only set gain in 0.5dB steps.  Fortunately, that almost matches the Krell.  Actually the Krell seems to change it's gain any about 0.3dB during the first hour of warmup.  The +1dB setting puts the Aragon at the low end of the range of the Krell, almost identical with the first minute of warmup.  If the DEQ had finer control, I'd likely set the level to 1.1dB or 1.2dB.

This 0.1dB matching for ABX testing is much more stringent than usually done in audio, notably more stringent than I've been doing for electronic balance (which I hadn't been paying attention to and just assuming it was correct since I have no variable resistance elements in my system…and now I see I had unintended differences larger than 0.3dB) and in setting up crossovers for triamplification (which I've done since around 1979 btw).  For many years I used a Pioneer D21 crossover (a Series Twenty beauty) and thought of it as about as perfect as such a thing could be, and it is only settable in 1dB steps.

For a few minutes, I was thinking my project of using DEQ's as crossovers was doomed because of the limited "tilt" balance control and 0.5dB steps.  But now I'm thinking "close enough for crossover" since even with the 0.1dB adjustability of the DCX units, I can't say my adjustments are anywhere near that accurate and I often play with changing levels by 1dB or more to see if a new setting would be better.  I recall differences of 1dB as being hard to tell apart and have never expected my crossover adjustments to be better than 0.5dB.

Strangely, IIRC, small differences in timing are more audible, with 0.5dB in level difference being not unlike 0.5 msec of delay, with even 0.1 msec being important (more important than 0.1dB).  0.1 msec is close to the difference of moving speaker or listening position 1 inch.

I just won a Denon 5000, my 3rd new R2R DAC.  I now have enough of them to do all three ranges in the living room system if I'm willing to use the same DAC for both midrange amplifiers, which I now think I will do since I have useable digital level adjustment with sufficient accuracy for a crossover (and almost sufficient for ABX).  I could even control the DEQ settings with a trigger voltage via a trigger-to-midi device.

I think I will implement a level-box as my ultimate Y adapter for the two amps, but in the meantime an Audioquest Y adapter will do, with low cap cables possibly from Blue Jeans.   None of the cables I am currently using are particularly low cap, though I could have done worse.  I was shocked to find that the 4 meter Monster 1000i or something like that (it was over $100 if not $200, IIRC) had 800pF and I decided that made it totally unusable.  But even the Straightwire 1m cable I have for the Krell is 300pF, and the combination of cables I have to the aragon is over 400pF.

I will need to get a rack.  The piles of equipment behind each speaker are already too high, and I needed to stack the turntable above the Aragon amp already…with a rack I can also support a couple of boat anchor DAC's and other stuff.  I've picked out a very nice audiophile grade rack and turnable stand, it will put the turntable at 48 inch height which is about all I can deal with.  Before finding the one I want now from Mapleshade in solid maple, the previous ones I was looking at had glass shelves.  It's looking hard to find the Lovan Sovereign I used to lust after, and even the Lovan Legacy that is even featured at Houzz.  There is a four point stand by VTI that looks OK for a mere $400, and even $100-200 glass stands at Wayfair look tolerable.  I don't much like the Sanus stand I have now under the keyboard.

I've been matching the Aragon to the Krell + Audio GD level because the latter has sounded so good, despite being different from my last DEQ Calibration in January.  I think I'm playing the midrange at a higher level now by about 2dB or so and that sounds better because it dominates the subwoofer bass, giving the sound a tighter electrostatic bass sound.   Or perhaps I should say it now equals the bass, whereas previous the bass dominated giving everything a plate-amplified subwoofer sound.  This adjustment needed to be done by ear anyway, it's hard to say precisely where one terrain of 10dB hills and valleys should be joined to another.

And so if I was wrong by 2dB during an actual calibration--with careful measurements and listening, just how critical is it to set level better than 0.5dB?

Monday, June 22, 2015

Determinacy is useless

One of the kind of thing I've been thinking of a lot about the differences in analog and digital…which generally means LP and digital…is that the analog sources apply their varying flaws (typically audible and near-audible levels of time variation, aka wow and flutter) so that not only do you hear something different every time (as you would do if everything were absolutely identical, merely because You have changed, especially having already having just heard it…) there is actually something slightly different there, and each time this difference may serve to highlight things differently and bring something different out.  Given that we are always going to hear something different anyway, it's not useless for it to actually be slightly different each time.

Of course the main reason why LP's sound better when they do is the mastering, and digital recordings of LP's sound very good to me (preferable to some CD's because the mastering was so much inter).  But they don't have That Magic, because the analog flaws at one time and place have been frozen, immortally.

It's not simply that hearing through the flaws lets us interpolate back to the ideal original--similar to the digital recording.  It's that they trigger more difference each time than we would otherwise hear, when we are listening to the analog.  The analog is, in it's way, a live performance.

Anyway, I think it is worth studying the psychology of of it all, applying science to the magic of the Placebo Effect and Audiophile Experience.  Not that I want to give the magic up, I want it all!

So I'm sure the techno freaks would say fine, we'll just add LP distortions to your sound.  I'm sure that will be a disaster for a long time.  But let me describe how it might work.

All the flaws should be idealized rather than sampled.  We don't want to simulate the things we don't really understand.  This is not sound, it is modification that attempts to retain the integrity of the original.  Therefore, it must have simple changes, not an accumulation of mud in order to be biologic.

(I criticize many of the presets of my Kurzweil K2661 synth for this.  They go for too much dirt and realism.  Of course you can program anything you want, make it all sine waves or whatever, or any sample, or just tone down the dirt channels.  But I'm lazier than anyone and I like the presets right according to me.)

And it's done in super high resolution, at least 48 bits of resolution, then dithered and so on.

And what I want is the ABX learning effect, where it choses from affects at levels not believed to be audible, or just above audibility, and you can guess at any time and move up to the next.  I want to be able to program the effects and their levels, perhaps specifying common wow frequencies and so on.

Of course I alway think there should be a geek version.

99 wins, one fail for DEQ

Discovering that I could easily program one passband of an electronic crossover for a multi-amplified system into a Behringer DEQ 2496, I have been planning to buy 3 more units, or something like that.  It turns out these are (mostly) the most versatile units I know of, nicely made, and cheap.  The have AES digital I/O, which is how I use them (forget the analog bits, those I want to avoid as much as possible, though I still am, mostly, and with little technical loss, they are objectively good enough when not used above 4V output not to have any proven audible flaws, but of course they are not built with audiophile design or jewelry).  And optical, so you can have two parallel outs (optical and digital…another fact I take advantage of).  Just the most useful little tool for me now, though I could dream of something similar and fully programmable, pop up a programming interface when you plug it into your compeer via USB, …

The DCX 2496 crossovers, which I still use except for the panel passband, don't have digital output.  If they just had that, they would be invaluable…though I don't really like the SRC they use, they convert everything to 96kHz.  The DEQ's don't do SRC, they pass the input to the output without changing sampling rate.  I prefer that, so I'd prefer that to having a modified DCX with digital I/O (I expect that would cost about as much as 3 DEQ's too).  The DEQ has a bigger screen, it has meters and spectrum analyzer…it's just cooler to have one of these for each passband than a DCX, except of course for the added cost and complexity.  But if you need it, you need it.  (Wait.  Why do I need it?)

Except, except one thing I wasn't expecting at all.  I guess it doesn't actually derail my plan, but it is a big disappointment, and it also in-general-now (but not wrt my Big Test, in the Long Run after I Work This Out) ruins my plan to use midi-programming of a DEQ to implement level changing for ABX testing.

The Behringer DEQ 2496 doesn't have separate level controls for each channel.  It's mind boggling that a thing with so many features lacks this one basic thing.  You can set overall "makeup gain" to 0.1 dB in the Utilities panel, which is fine though it seems peculiar to relegate so critical a thing to the back door, but there is no separate Right and Left or whatever, anywhere.

What the Behringer does have is a "Rotation" control, that allows you to set "Rotation" (something like balance) to 1 degree.  But that is not close to being good enough, has a non-linear relationship with the dB difference, and inconveniently affects both channels at once (in the opposite direction).  Even with a mere 0.3dB difference between the channels of my Krell, 1 degree of rotation overshot the mark.  I was easily able to dial in the correction on my Tact RCS 2.0, which had been set to 0/0.  (I had been worried that previous adjustment had been the cause of the 0.3dB difference.)

So this won't work for fine tuning levels for ABX testing.  It's basically good enough for crossovers in my system.  I can adjust the all-critical wide range middle speaker using the Tact, the subs can be adjusted with their own controls, and I have no idea how many dB wrong the current super tweeter balance is, and they are effectively inaudible at the listening position.  (If I do need to rebalance the super tweeters because they are noticeably different, as they look, quite possible the rotation control will be sufficient--that's about audible difference generally--ABX testing is actually to a much higher standard.)

So, for ABX testing, I'll have to use some other level adjustment-in-general-and-now, AND I have the sad knowledge that the Aragon has quite a bit less output than the Krell, not the reverse, so the Krell would need to be attenuated, and that Won't Do, so any arrangement will have to be temporary or something.

However for general use, the Midi control with 0.1dB control regarding level (if not L-R) will do fine, and that may do (with some adjustment/correction) even for a permanent Krell/Aragon installation.  I'll get the L-R balance of both perfected through other means, then changing the overall level is all that's needed.

Other things should have their balanced fixed first also.  So the Only thing we absolutely need is level (real L/R control would have been nice, somethings won't be testable, even right now they aren't, and I'm not going to put permanent attenuators of any stripe on the line to the Krell, I just won't.

The Krell has been sounding marvelous, btw.  Over the weekend, listening to FM mainly.  I was even drawn to Opera for awhile.  I had to setback the thermostat first 2 degrees and finally 3, taking back the 3rd when I put the Krell in standby.  Standby ended on Sunday night, though I've had the Krell on tonight for testing as described above.

I'm OK with raising the thermostat if I can have my Krell.

Apologies to those who say everything must be scientific.  At home, in my closet of a living room, I practice magic.  Magic requires suspension of disbelief.  The magician makes big sacrifices, lifts the Krell up onto the altar, and everything has a purpose…