Sunday, September 24, 2017

Help, Part 8

Science, Magic, and Gambling


Now, I think, this is where some of my thinking, anyway, begins to join the dark side.

Science speaks not in terms of absolute truths, but probabilities.

Now, this might not help you much when the probabilities are six nines against you.

It depends on the downside, whether I'd consider taking another roll.

Some of the things we know about how well we can extract the information from a musical event or audio are pretty certain, others not so much.

The detectability of out-of-band information may be in the lesser assurred category.

For example, our ability to detect ITD is conservatively estimated at 20 microseconds, equivalent to 50kHz frequency response.  Some are claiming detectability of ITD at the 1 microsecond level.  The actual importance of this to imaging may be easy to overestimate, since ITD is only one thing we use, and we use it mostly at low frequencies.

Anyway, audio does present a smorgasbord of scientific questions you may or may not consider partly open, along with many other kinds of questions, including those in the domains of engineering and psychology.

If you want to believe that this or that is audibly better, when it contracts what I consider well established science or engineering, who am I to stop you?

I suppose, if I were on a consumer crusade against unnecessary audio technology, I might.  But, I'm not.  I don't see excess audio technology as not a major threat to human society or the environment.  And to some degree, the flaming of certain cults, such as those involved in preserving older equipment, might be beneficial.  Audio generally is low impact as compared to many human activities, even many of those related to "appreciating nature."  Mind you, if you are concerned about such things, I recommend such bandaids as I apply myself: recycling (through legitimate electronics recycler) the least resellable equipment, or donating, rather than trashing it, and using green electricity--otherwise I might feel guilty about my endless pursuit of Class A amplification.

Now, I think it's best to have a realistic assessment of the posssibility your tweak might help.  But there's no great need for that.

Audio itself is disbelief in the apparent reality, that you are listening to a music event, and not a contrivance of electronic engineering.

So this is another way of saying, that audio is at least party a "magical" event, in which we fool ourselves, or allow ourselves to be fooled, much as with stage magic.

So, if fooling oneself is essential to the greatest appreciation, why not fool yourself a bit more?

Why not believe that the latest trick "is" going to do something, despite serious evidence that it would not?

If it helps keep you going, who am I to say that's wrong.

And in fact, I'll egg you on a bit.  I'll say that low probabilities are not zero probabilities.

You could be right, though I would not bet on it.

I'm busy covering a few of my own bets.



Friday, September 22, 2017

Help, Part 7

The 'Philes.

Long ago, about the same time as one audiophile friend lost his high frequency hearing while doing all the metalwork required for his very massive Leach amplifier, another audiophile friend derisively dubbed those he considered more interested in building equipment than actually listening to music, "Build-o-philes."

Having built and modified some equipment myself, and having been an avid reader of Audio Amateur, I found this somewhat insulting.  So, I coined my own term for people who endlessly like to make arguments about audio and audiophiles, "Argument-o-philes."

Though I felt then, and still do, that however people want to play, subject to the usual constraints, is well and good.

And, being an "audiophile" means only that one is "enthusiastic about audio," and not that one necessarily has fancy audiophile cables, or even listens to music.  Not that I'm saying anyone doesn't.

That was where this kind of argument stated long before.  The newly rising subjectivist audio reviewers wanted to distinguish themselves from the prior (and continuing) generation of objectivist "meter readers" by claiming the mantle of loving Music.  And, of course, music is this holy thing, that brings us peace and joy and saves our souls.  Of course it's what Audio is about, it's what Life is about!

So hence, even in the pages of the gearhead oriented The Absolute Sound, endlessly reviewers would claim the banner of being Music Lovers for themselves, in some cases in opposition to being Audiphiles.  "Oh, we're not Audiophiles, we're Music Lovers."

Now, I have known several Music Lovers who were not audiophiles.  They were not interested in equipment At All.  They had handed-down or thrift store or box store "record players."  They had lots of records, indeed costing far more than their equipment.  They were easily distinguishable from Audiophiles and would not even have heard of magazines like The Absolute Sound. Given the potential of introducing audiophilia nervosa, I would hesitate to even attempt to make people aware that there is anything better, unless they are asking for it.

Of course, there is little wrong with being that kind of music lover, especially today, when, contrary to much opining, good sound can be cheap and easy.

But there is nothing wrong with being a build-o-phile, an argument-o-phile,  measure-o-phile, or whatever.

Even if there isn't much value in getting harmonic distortion (and hence IM) down farther and farther below the 1% level where it can reliably be heard, it's an interesting challenge, possibly rewarding,
and potentially of considerable value to society.  Low distortion amplifiers are needed in virtually all technology.

And, virtually all humans love one kind of music or another.  I don't mean to suggest otherwise, but merely not to sanctify it as the ultimate source of all human joy and satisfaction.  It's good, but it's not everything all the time.  And I don't think it's fair to denigrate people who have interests in technical things, though the rise of subjectivist audio reviewing often seemed to do that.

I acknowledge being an argument-o-phile myself, though I'm also in many other 'philes.



Thursday, September 21, 2017

Audiocorder and other stuff

For decades, I used timer recording systems of various types to record FM radio programs, just as people use VCR and their modern equivalent HDR to record TV programs.

My Nakamichi 600 had a timer start mode which causes the unit to start recording when power is applied.

My Nakamichi RX-505 has the same feature, and I have used that as recently as a few months ago to record FM radio programs.

I even had a Sony all-in-one music center (a small box) which had the feature, which prior to 2006 I used to record daily radio programs for playback in my car.  It had been fairly hard to find that unit.  However, after 2006, the march of "progress" eliminated the cassette player in my latest car.

This was a huge step backwards for my personal connectivity.

While there were supposed to be digital alternatives, I found none so convenient.  For example, in order to use podcasts, I needed to connect my iPod to my computer every day and fumble around with iTunes.  For various reasons, this often didn't work, and it was ALWAYS more of a hassle than simply popping a cassette into my all-in-one recorder had been, and finally I gave up.  If the internet radio didn't specifically make a daily "podcast" you couldn't just record a particular program at a particular time.  It seemed to me there is a conspiracy against timer recording.

Perhaps there are timer recorders for digital radio now, I haven't looked.  More recently I use smartphone apps to listen to specific programs I like....however this doesn't help if no one has created a suitable app for the program you want to listen to (and there are several programs like that for me).

Anyway, here is Audiocorder, which lets your Mac operate like a timer recorder for audio.

Then, using an extra program they suggest, you can get it to record internet radio also.

Now, stepping somewhat back from High Fidelity, another interesting recordable thing out there is Pirate Radio.  Some of these are on FM because virtually all listeners already have the required FM radios. But most pirate broadcasters are probably sitting in the less intrusive/detectable/complainable regions of HF (say, 6.7Mhz).  I can pick that up with my new General Coverage Receiver (at least, as soon as I get the antenna set up).   While FCC often shuts down pirate radio stations in the FM band (they say, they only do this if someone complains, which is probably accurate) I doubt they have much time for the non-amateur parts of the HF bands and many pirate stations there are legendary.

Here's one list.

And here's another.

HF Underground is showing a bunch of loggings from today.

And of course there are fully "legal" HF broadcast "shortwave" shows also, but books are filled with info on that (including one book I just bought).

I suspect few radio amateurs would risk their own hard won licenses running a pirate radio station.  But I've known hams tell me right away that pirate radio is among the best stuff to listen to on HF.




Sunday, September 17, 2017

Help, Part 6

Around 1970 Saul Marantz was interviewed, and I remember hearing it on a Los Angeles radio station.

Marantz said he went a different way than others of his generation, and that was what led him to perfectionist audio equipment.  By following his own path, he discovered new things, created a successful company, and opened up a new arena for others.

(I recall the introduction said Marantz "invented" high fidelity--it appears to have been invented many times, and still nobody knows what it is.)

Anyway, for what it's worth, that idea of following your own path seemed right to me then and ever since.

Just because "all audiophiles" are supposed to do this or that, I not only feel fine doing something differently, I feel it is good.  Everyone doing the same things would mean little new discovery.

Saturday, September 16, 2017

Help, Part 5

To EQ or not to EQ

The argument I have often heard advanced against deliberate equalization is that it introduces errors in the phase response, or the time response.

What is not understood, is that when deviations from uniform (aka flat) response occur, they have already introduced errors in the phase response and the time response, and that using EQ to correct these deviations actually restores all three at the same time: the frequency response, the phase response, and the time response (and this is because they are all, essentially, aspects of the same thing...the signal itself).

Now, this is generally true, which means in some cases it may not be true.  But in specifically what many people believe is the most troublesome case, room EQ (to uniform response), famous TAS audio reviewer (and Professor of Mathematics) Robert Green claims that room response deviations from linear reflections, which most are, are minimum phase, and hence are corrected by the inverse deviation.

So far from being horrible, correct EQ is beneficial to the phase and time.

Now this is not to exaggerate the importance of phase response.  Large volumes of research show it is not audible to surprisingly large rotations.  Anyway.  In all cases like this, existing research doesn't prove it won't be audible at this or that time.  But, if you want to prove you can consistently hear it, it's probably going to be hard enough that you wouldn't bother.  So, if it so hard to hear, it can't be too horrible, can it?  Not to say the challenge of getting perfect time response, hopefully w/o sacrificing too much else, and appreciating it as one can, can't be a fun endeavor on it's own.  But existing knowledge doesn't suggest it's worth sacrificing many other things, notably the frequency response, for.  In most cases.

Then there is the matter of what you might call, deliberate non-uniform response.  Now, those indeed will be adding time and polarity deviations, along with the frequency response variations.  But this is the natural way these things occur, and are generally accounted for in only describing the frequency response (not the "horror" of deliberate EQ in particular).  So if you were, say, achieving the same result with some tweaky infidelity, exactly the same and not added distortion or whatever, your tweaky response correct would have the exact same effect on the phase and time as a deliberate EQ system--preferable a digital EQ but some high end analog EQ's are truly high fidelity also (such as the Cello Pallete).

Now, before the days of digital EQ, analog EQ's had lots of practical issues, including but not limited to distortion causing devices.  It was rare to find a really good one; before the Palette, I'm not sure there was.  Now, with digital input and digital output, a cheap digital one can be as perfect as the 24/96 audio it puts out (in the case of the Behringer 2496) when you use full digital I/O.  The distortion is many zeros below the decimal point, the noise level is better than -144dB.  Jitter does not appear to be any higher in the output than in the input...it does not appear to add to jitter (nor does my whole chain of processors and converters)--and once again not to exaggerate the importance of jitter, but just saying.  And of course, precisely the filter you wanted, with no pole out of place.

Designers of loudspeakers have long understood this, and the importance of compensating for driver impedance and response in the crossover is done.  This is just another form of deliberate EQ, often with somewhat precision-limited parts, but often very carefully considered designs ("engineered"). And correcting the driver response corrects the phase as well.  However, most crossovers do introduce group delay and some time dispersion.  Virtually all scientists, engineers, and manufacturers do apply more crossover than the minimum: just lowpass on the tweeter, the 1930's standard.

The primary issue involved here, IME, is loudness uncompensated listening comparisons.  Without compensating for the difference in efficiency, a more minimal crossover will play louder, and hence have a large tendency to sound better.  If drive power can be increased without issue, the less efficient corrected response, done correctly, would be preferred.  Not that there aren't limits as to how far this can be done without diminishing dynamic range.

Since the scientists, engineers, and manufacturers generally do level adjusted comparisons (though perhaps within a desired range of efficiency) they find the more complex crossover to sound better.

Subjectivist gurus do not do level matched comparisons, so the more minimal crossover sounds better.

The same issue, typically combined with sighted expectation bias and other biases, explains a lot of tweako beliefs, from power conditioners (maybe not a bad idea, but not with the massive benefits claimed), expensive audiophile cables (which if they do anything at all to the sound is probably destructive to simple well made cables), lack-of-feedback, single ended, and NOS.

In every case, if there are actual changes, people may find they prefer them, for highlighting this or that, but perhaps also what people find they prefer in casual testing might not over the long term be appreciated as well.

I think it's very risky to try to achieve fidelity through infidelty, other than correctly determined and deliberately applied EQ and possibly out-of-band filtering.

But, it's your roll.

Now, why does loudness, even trifling amounts, make things sound better?

Because it increases our auditory S/N, and opens up a far greater amount of information.

Now one thing to be clear is we never fully absorb the information of even the most limited presentation.  So why do we need more information?

Because it gives our auditory system a greater sample to choose from; it opens up patterns that previously were hidden by noise (most often...household ambient noise).

Now, there are limits to this that vary a lot, and playing so loud as to cause compression (not to mention clipping) may be undesirable (especially, compression in your own hearing system).  And as I posted before, actually avoiding current or voltage limiting may be far harder than people recognize.

Which is another thing.  Unless you have very high efficiency speakers, or even so, you may need far more power than you realize.  In practice, little spikes of peak power are required up to alarming amounts.

Sanders' estimate was 500W for typical dynamic loudspeakers.

That may be a bit high for typical dynamic speakers.  I would think 100W for kiddie speakers, 200W for serious speakers, and 300W for inefficient high end speakers.

But there I am, giving advice again.

I see John Curl describes his friend Dick Sequerra's Metronome speakers as "kiddie speakers."  They're small, with small drivers, though possible do require more than 200W amplifier.

Anyway, they take clean impulse response to an exteme.  The crazy looking tweeter and weird woofer do actually deliver very clean impulse response, hence the name Metronome.  However, the frequency response is way out of whack, and finding the right "location" may be problematic too.

This is the example of sacrificing much to get the perfect impulse response, an ultimate tweako goal (since the serious scientists, engineers, etc, don't consider it THAT important, though never discounted entirely, and there is some room for doubt).

They do have amazingly well focused imaging, though not all people like that either.  But many people who try them for awhile find they dislike some aspect of this approach.  I'm sure I couldn't stand it at all, though it might be interesting to have a pair for an imaginary magic show.

So that's what they are.  Stage magic equipment.  A good description also of high end tweako stuff which is less well engineered.



Help, Part 4

My friend Tim has intensely studied many transistor and tube characteristic curves for decades now.  He's a very technically and mathematically astute.  He's also done some test building over the years, but mostly his beliefs come from studying the curves and the mathematics.

He says now that push pull BJT* amplifiers work best in Class AB, not Class A.

Of course this flies in the face of everything I've ever read, heard, or thought about, and my most prized audio machine is a Class A amplifier, because I've long been a fan of Class A amplifiers and my belief that they are best for electrostatic speakers.

He agrees it flies in the face of standard and conventional thinking, but insists that nevertheless it's true.  His argument is that the "cutoff" distortion on one side precisely works with the changes on the other side to produce the lowest distortion at some particular AB bias.  Class A doesn't get this benefit, and produces higher distortion.

He's been wrong before, so he could easily be wrong this time.  My suspicion is that it either misses other factors, and/or

But, if he's right, and in many cases even if he's wrong, it's quite possible that Nelson Pass's Threshold amplifiers (which were BJT, he switched permanently to MOSFET after leaving Threshold) were sub-optimal.  The attempt to eliminate cutoff, Tim affirms, would produce higher distortion than the correct Class AB, and would therefore produce higher distortion than necessary, and at higher operational costs.

That's certainly true of some other of Nelson's designs, such as many devices in the single-ended Aleph era, and many of the First Watt designs.

Is this a big deal?  That through charisma or whatever Nelson sold higher distortion amplifiers than necessary?

Firstly, I suspect all the Threshold amplifiers all had distortion sufficiently low, and with sufficient reliability, and relative high power and current into most loads, to be considered fully High Fidelity Amplifiers, such as there is no respectable evidence that people can hear differences between.  So the "loss" to the users of Threshold amplifiers is nil, by the audio objectivists very own standards.

They've been loved, held their value, etc, etc.

So, that's fun, entertainment, and playing music.

Secondarily, when the actuality doesn't really matter, the only thing that does matter is the story.  The story says lower distortion, greater PRAT, or whatever.  The story makes you feel good.  The increased distortion is irrelevant, in most cases, even in many extreme cases where people just seem to groove on the distortion.  Minimum distortion I would generally look for, myself, as much as I can afford.  But if other people like other stories, other presentations ever, that's their thing, at least while it lasts.  I think, in the end, as little as possible distortion, combined with the greatest flexibility (the equipment is supposed to let us Play music, not have Music imposed on us)

I believe many of the beliefs that modern distortion reducing methods create bad sound are myths, having perhaps vanishingly small examples, and none where proper engineering has been done.

But there are actually many different circuits, it's hard to say we have an "optimal" circuit as such, and if we don't have an optimal circuit, then we don't have an optimal class, and so on.  Furthermore some things may create more or less distortion than other things under some circumstances, and have the reverse be true under others.

In fact, as is well known, people love the higher distortion circuits like SET's and transformers for various reasons.  And since this is about fun, not Accurate Reproduction, that's fine, for them, as long as they continue to do so.  And much as I might think it would happen, many people are sticking with one of many higher distortion than necessary paths.

We don't hear distortion very well anyway.  It's the frequency response under load we hear mostly.  People are finding or not the EQ they want.  Some people fear EQ.

Many like me fear this is an expensive, and even more than that, difficult and ineffective way to get very much EQ.  But if someone thinks it works for them, it works for them, fine.

I have actually experienced a "solid state" "dryness" (in a malfunctioning Citation 11) which couldn't be eliminated with (it's very own) EQ.  That happens when you have higher noise and IM than necessary.  You can't EQ that away.  But EQ works quite well for most other things.  When we have digital sources, we can have distortion and noise free EQ, which provides exactly the alteration needed or desired.

EQ lets me easily and precisely play with how things are played, and that's become very important to me.

(Tim variously prefers and not prefers MOSFET amplifiers in Class A.  He has most often said MOSFET amplifiers require very high bias to be in their most linear region, and for practical reasons (would it require liquid nitrogen cooling?), nobody ever does that.  But he may be softening on the bias levels needed to make MOSFET preferable to properly biased Class AB+ BJT's.  I think there may be other factors and ways of looking at the situation.)

Friday, September 15, 2017

Help, Part 3

I have a very simple answer to the question "What is Audio" and I believe my simple answer quickly refutes those stubborn audio objectivists like Peter Aczel and Floyd Toole who say that "Audio is Engineering, Music is Art."

Fun.

Audio is not just music reproduction  Audio is fun, and fun is the ultimate principle that it's all about!

And so of course it is true.  Audio is a hobby that audiophiles passionately follow, and just like all other hobbies, it's ultimately about having fun.

Then I suppose it could be argued that professional audio is different, professional audio is the engineering which serves the creation and reproduction of music.

But even there, and especially for Audio, if your job isn't fun, as many say, you should get another job!  (With the slight disclaimer nowadays, "if you can.")

I'm glad we've gotten that straightened out.

The creation of fun is not something that can be engineered, though the relevant engineering should applied where it needs to be, or it's not going to be fun very long, if at all.

But indeed it does help that we have Entertainers like Nelson Pass*, one of the more fun people in Audio.  He's a very good engineer also, it's easy to see.

(*Pass described himself as Entertainer in a recent Stereophile Interview.)