Do equipment stands have an impact on electronics?

I used to have troubles with footfalls when I ran my turntable.

I got a Sound Anchors stand which helped quite a lot but did not solve it.

I used to have a Sota Cosmos; replaced it with a modified Empire 208 turntable (equipped with an SME5 arm). It sounded better than the Cosmos until you turned up the volume, then the Cosmos sounded better at volumes above that (the Cosmos had a fair amount of damping control; the Empire did not).

I solved that by going back to Sound Anchors and had them build a stand that was customized to accept an anti-vibration platform (Ultraresolution Technologies) for not just the turntable but also the preamp. Now I could play much higher volumes without strain using the 'Empire' (which was further customized with a new plinth machined of solid aluminum, damped  platter which was machined to accommodate a better platter pad and the arm was replaced with a Triplanar). I still got some footfalls. I added some Aurios Pro bearings beneath the footers of the stand and the footfalls were gone.

Now I can play the system to some really high volumes (+105db) and it always sounds relaxed with no hint of strain, and its really hard to tell how loud its playing unless you try to talk to someone beside you.

IMO/IME its really important that that the system have the ability to not sound loud even when it really is. An orchestra can play peaks of 115db; the stereo should not add anything of its own during playback. At high sound pressure levels vibration can affect turntables, CD players and all electronics whether tube or solid state (if you think transistors are immune to microphonics you've not spent time working with them!).

So a stand with vibration control for the front end of the system (sources and preamp) is not only in the signal chain but can be considered a component in its own right. 

That's great feedback Ralph and describes precisely what I have experienced.  Since you are an engineer and manufacturer like Geoff, any thoughts on why SS devices would be vulnerable?

The semiconductors themselves are microphonic. I've seen some (in need of replacement obviously) that rang like a bell when you ticked them with a small screwdriver, just like a tube.

I've also seen cables and capacitors be microphonic. One time a highly respected high end cable manufacturer made a set of cables for our Neumann U67 microphones, which I was eager to use, but regrettably the cables were so microphonic (tapping on them was easily heard at the mixboard) that they could not be used at all! The stock Neumann cables made much less noise.

Does vibration of any form effect electrical performance in electronics and why?

The why is microphonics. The devices affected are tubes, transistors, film capacitors and cables.

The most microphonic tubes I've seen are frame grid triodes of the 6DJ8/6922 family including the so-called 'super tubes' like the 6H30 and such.
The most microphonic film caps I've seen were military hermetically sealed Teflon caps. They rang like a bell. All film caps have some microphonics though.

I've seen microphonic transistors too. Some so bad that they simply had to be replaced. Usually they have very low microphonics but if you think they have none you're living in a fantasy world.

I've seen interconnect cables make noise simply by moving them. Some cables are far more susceptible than others. Cables are often used inside equipment as are caps, tubes and transistors. So it makes sense to keep the equipment as still as possible for best results.

This is not anything new. The table for our LP mastering lathe is set on adjustable points. The table was made in the late 1940s. On top of the table sits a damping platform on which the lathe resides. It is coupled to the platform by adjustable points.

Inside my Ampex recorders its really obvious that the designers were going to some lengths to reduce microphonic effects, and not just for the sake of the tubes.

So this really should not be a surprise to anyone that this stuff is audible and measurable. The damping controls have in some cases been understood for over 60 years!!

I am still waiting to hear from you or anyone else a corollary in audio. Furthermore, even if you could lock into a given finding, would blinded audio nerds or lay people know the difference?

I’m sure I’ve mentioned this before in this thread, if not, I’ve mentioned it elsewhere so here it is again:

We own a Scully LP mastering lathe equipped with a Westerex 3D cutter head. You can see it on our facebook page. The lathe sits on a special anti-vibration platform via a set of adjustable stainless steel points. The platform in turn sits on a custom table built for the lathe that also has adjustable points going into the floor. Now the lathe, platform and table were built about 1948 (the cutter head about 1959). Clearly they understood the issues of vibration affecting performance that long ago.

Are suggesting that things that we knew nearly 70 years ago ago is no longer knowledge? Or are you just not aware that the history of stands and things like anti-vibration platforms and Tip-Toe-style points have been around a whole lot longer than you thought?? Clearly the effects are measurable (and audible too) and its not rocket science as you’ve been suggesting.

What kind of spurious signals and how was it measured?  Anyone?

That should not be hard to do. Place a preamp on the stand to be tested. Run the volume up with a shorted input (phono would be best). Subject the preamp in the stand to a 20Hz tone measured at 90 db at the front panel of the preamp. Observe for the change, if any from the output.

Ethan Winer has made a lot of people mad over the years, and has been banned from multiple forums for doing so.  

Part of that is because the guy tends to be a bit of a troll. For example, once he made the claim (and likely still does) that power cords can't make a difference- 'it's a power cord!" was about all you could get out of him. I challenged him to show his measurements, since he's a measurement guy. The funny thing was he didn't have any, and I did. They were pretty easy to obtain, too. When I pointed out that we could see a more than 2 volt drop across the power cord his instant response was that the power cord was a piece of crap. Now that struck me as trying to have it both ways; apparently even by his testimony power cords can make a difference even when they don't.

Then it turned out that his reference amplifier was a Pioneer (keeping in mind he is anti-tube) integrated that cost $600.00 (and as you might expect it did not have an IEC connection to allow for easy power cord exchange...). I and others tried to explain to him that the larger heatsinks, better quality components, larger capacity power transformers and filter caps in the power supplies of high end amps actually made a difference but he wasn't buying it (literally).

After all that he finally did get banned from that site. I don't find him all that credible and often a bit obnoxious, but that's me.

Sure- why not? Same test, just using the Diament system.

If you did this all with a sweep tone, it would be possible to show the strengths and weaknesses of the 'isolation' system under test.

Sound Anchors did something very much like this- only they bounced a laser off the surface of the loudspeaker that was mounted on the speaker stand that they were testing. The less noise that the reflected laser beam showed the more effective the stand. They were doing that a good 25 years ago. 

There were no speaker isolation stands 25 years ago. Not in the literal sense of the word, anyway. 25 years ago vibration isolation was not even a gleam in some audiophile's eye. Using the laser as you described would not give a sense of how much energy from the speakers was being fed back into the front end electronics via the floor. I’m getting that feeling again we’re not on the same page.

This statement is false. Sound Anchors was making stands for exactly that purpose prior to 1991. We showed with them at CES in 1993.

Here’s the thing: When someone makes a claim, the burden of proof is on them. It’s not up to me to prove that a 2 volt drop doesn’t have an audible effect. It’s up to the claimant to prove that it does. This is Logic 101. More important, trying to assess the affect of a power wire by measuring the AC power voltage is beside the point. The *only* thing that matters is what happens at the output of the connected equipment. Competent audio gear is immune to small changes in voltage, and routinely filters out the typically small amount of noise riding on top of the power voltage.

As always, I’m glad to be proven wrong, and I promise I’ll change my opinion immediately. But in all the years I’ve been at this, nobody has ever provided such proof.

One claim you have made is that power cords don't make a difference. But you refuse to provide any numbers (measurements) to back up your claim. So as you say the burden of proof is on you. When in one case you refer to above where we measured that 2-volt drop, it resulted in about a 30% power loss. It was not only measurable but also audible.

The problem here is that you don't get that some people run higher powered systems (not just a $600 Pioneer integrated amp like you have, but real amps that actually make a lot more power with less distortion). Those pieces (like a large Krell, Gamut, Parasound or Pass Labs) can draw enough power that you do have to take the power cord into account.

The wiring in the wall does not have to be flexible and in most modern homes as a result does not see the same voltage drop. You know you have a problem if your power cord is heating up. If the cord is built into the amp like it is in an integrated Pioneer, you won't ever be able to tell what effect the cord is having.

You say that bouncing a laser off of a cabinet of a speaker is not going to tell you anything about the effect of the cabinet, but you don't have numbers to back up your claim. You're not the only engineer that's been around 40-45 years (sheesh).

Sound Anchors did that test simply to show that of two speakers playing the same test tones, the one on the stand clearly showed that the cabinet was vibrating less. A microphone in the room verified that the speaker on the stand was making less distortion. With a lot of cheap speakers (like the ones you like to use), it happens that cabinet vibration is part of the bass output of the speaker. If you can reduce it, there is less coloration. There is a correlation between the lower vibration and the sound of the speaker (less vibration- more neutral). Sound Anchors showed this 25 years ago. One of the biggest loudspeaker manufacturers in high end audio (Vandersteen) used the Sound Anchors stands for quite a while (until they developed their own).

Ethan, you've been pretty good about your comments regarding digital. But most of your other comments really only apply to mid-fi. Despite your remonstrations you don't seem to operate in the world of high end. Instead of using hubris to make your way, maybe instead it would help to learn what some of the challenges of what happens when you have more power and **in particular** transparency.  A $600 amplifier isn't state of the art and had no intentions of it in its design- its intention was to make money off of the buyer. There's a pretty big difference in high end audio where the intention is to see how good the reproduction can get, and the envelope has been extended quite a ways past a $600 Pioneer!

Atmasphere, I never said (or meant, anyway) that power cords don’t make a difference. Obviously using 22 gauge wire to feed a 1,000 watt amp is inadequate. What I’m always careful to say is that replacing one competent power cord with another is foolish. I’m certain you know you misquoted me. Why do you do this? Are you in the business of selling audio equipment?

Hmm. I can point to a YouTube video (and have in the past) where you contradicted (with vehemence) the first sentence in this paragraph.

The statement above is quite a bit different from your position that you held back when you got banned from the WBF website.

I am not aware of misquoting you; if you are now maintaining that a power cord should be a competent one then I have no beef. On that basis we can then state unequivocally that you think power cords can make a difference. Please do not accuse me of putting words in your mouth as anyone can see that is not the case. You simply maintain that a power cord should be competent (your text above), and that's good enough for me.

I'm not a particular fan of outrageously expensive power cords either. I do feel if a power cord is touted for its merits (or not), then it should be possible to measure the effects of the power cord easily enough (and have easily shown that to be the case). I don't take anything for face value as I have found that if you think about it long enough, its likely that you can find a way to measure the effects of that thing.

Regarding my anonymity, you are mistaken. I make no secret of the fact that I am associated with Atma-Sphere Music Systems; that is why my moniker is atmasphere. . Many of the people on this forum are well aware of that.

Apparently you replaced your Pioneer. What are the self powered speakers you are running now?

Regarding Geoff, I am sure you will find his posts amusing. He also maintains that signal moves through a cable via photons. And says he worked for NASA. I'm sure you'll give him as much credence as I have.

For the record, I still use my Pioneer receiver, and it cost all of $150 at Costco. It offers six reasonably hefty power amps with max distortion of 0.1 percent. This is not great, but it’s surely better than any tube amplifier! At full output of 110 watts with all channels driven the distortion is less than 1 percent. Since I use powered monitors and a killer powered SVS subwoofer, the Pioneer’s amp distortion is irrelevant anyway.

You are incorrect (you must not have seen the 'Specifications' link that appears on each of our product pages), we quote a distortion spec on all of our amps and apparently its lower than your Pioneer and composed of a spectrum that is less irritating to the human ear. So- 30 watts is the lowest power we make- the largest is over 500 watts. What is the value you regard as 'low power'??

Ethan, you must be aware that tubes were considered obsolete way back in the 1960s or 70s (depends on who you talk to). But for some reason, the market has chosen to keep them around. Normally when a technology goes obsolete, the only place you see it after that is at antique shows or junk shops. This isn't happening with tubes, which suggests that they might do something that the market likes.

Turns out it has to do a lot with how the human ear/brain system perceives sound (if you are an engineer, I am now suggesting to you that understanding how sound interacts with the human physiology and then applying engineering to take advantage of those perceptual rules is the key to building better sounding audio equipment; the fact that the audio industry in general ignores these rules is why you see so many subjectivists).

It is inside of that conversation where it is possible to understand why your Pioneer actually has **more** perceptible distortion than many tube products which on the bench otherwise have a greater THD, although I agree that its use on the sub takes care of some of that problem, although I can point to other issues that make it unsuitable for playing bass correctly.

If you want to know more about this, I suggest you read the writings of two of some of the best solid state designers alive today- John Curl and Nelson Pass (both of whom can do considerably better than Crown or Sony). They both understand that it is the higher ordered harmonics to which the ear is most sensitive (and not the lower orders, the 2nd, 3rd and 4th). The ear is sensitive to the higher ordered harmonics because it uses them to ascertain how loud the sound is. Your Pioneer, which is apparently a high distortion amp by solid state standards,  has a lot more of those higher ordered harmonics than our amps do; in fact most solid state amps (even those with very low THD figures) are also higher distortion than our amps in this regard.

In case its not clear, our amps were designed specifically to not make higher ordered harmonic distortion, while at the same time keeping the lower orders and IMD down as well.

BTW, our amps are fully differential from input to output, and thus don't feature the 2nd harmonic in their THD.  Have you ever wondered, if triodes are supposed to be so linear, how come it is that tube amps usually have more distortion? A lot has to do with topography. A lot also has to do with the fact that tubes don't need as much feedback on account of that linearity. We don't use much in the way of feedback at all in our amps.

So these large companies hire the very best engineers and designers they can. And for the most part their products reflect that. I’ll take a $400 Crown power amp over some BS $15,000 amp featured in Stereophile every day of the week!

I can point you to a simple example of how one person can do what a large well-funded company can't. Google 'Rohloff hub' and you will see a 14-speed (internally geared) bicycle hub designed by a single German engineer. It is durable and refined in every sense of the word. Compare that to Shimano's Alfine 11-speed hub; Shimano came out with their 11-speed to try to horn in on the market Rohloff created; needless to say they failed miserably- the Alfine was a disaster (the hub is is weak, shifts poorly, has less gear range and fails without provocation). Shimano is one of the largest players in the bicycle parts world, and yet for all their 'expertise' they couldn't get that one right to save their lives.

BTW I happen to use a Crown power amplifier with my keyboard setup. Its not a bad amp, but in no way can it keep up with actual high end amplifiers. But it is lightweight (class D, 22 pounds) and makes good power (500 watts/channel) and so is very practical as a keyboard amp.

$100 says none of these believers will ever post a measurement or other proof showing the affects of vibration.

I've posted this before Ethan, but this is a long thread and I don't blame you for not wanting to wade through it.

I own a Scully LP mastering lathe equipped with a Westerex 3D cutter. The lathe itself has 3 feet which are carefully machined stainless adjustable points. They rest in turn on an anti-vibration platform in machined cradles; the platform in turn employs softer feet and rests on top of a table built for the lathe and platform. The table also employs pointed adjustable feet just as the lathe itself does.

Clearly this is an attempt on the part of Scully to control vibration issues and for obvious reasons. It has to be able to make a silent cut on the lacquers it cuts. You might be interested to know that its quite good at that- a lacquer cut on the lathe is so quiet that no matter what your playback electronics, they are the noise floor and not the groove itself. That puts the groove noise easily at about -95db. Obviously things are different when the actual LP is produced! Apparently the pro audio industry recognized the possibility that vibration could be a problem and dealt with it in many of the same ways that audiophiles are using today. My lathe was made about 1950 or a little earlier, so these techniques you might say are 'time honored'.

(as a side note, Acoustic Sounds (Salinas, KS) recognized that vibration was playing a role in the surface noise of the LPs they were producing in their QRP (Quality Record Pressings) facility and so modified their pressing machines to not vibrate whilst the LP was cooling within during the pressing process. We've done a couple of projects through them and the noise floor is impressive- very nearly that of the lathe cuts themselves.)

A further example might be an Ampex 351 tape electronics chassis, which incorporates isomeric isolation on each of its circuit boards. Clearly Ampex engineers were concerned about the effects of vibration as well.

The Marantz 7C preamp employs an isomeric isolation technique on the subchassis of the preamp. This is clearly done to reduce vibration sensitivity.

We use isomerics to isolate our circuit boards in two of our preamps as well as intentionally dissimilar resonances in the various parts of the chassis which cause the chassis to be quite dead but I am assuming they don't count in your challenge. 

A further example of vibration awareness in the industry is demonstrated by Technics in their SL1200G turntable which is not a reissue of their older SL1200 although it looks like it at first blush. But in closer examination, it is seen that the turntable employs 4 different methods of reducing the effects of vibration including damping the platter itself.

These five example easily show that vibration has an effect and are the proof you are asking for.  I nor anyone on this thread is expecting that you will actually come through with the $100 but if you are your word then I am easily enough contacted. Of course, an out for you is that I'm not a 'believer' so much as a 'knower' and there is a profound difference! Your quote does refer to believers so I am probably disqualified.

Incidentally it appears that your comment about LPs is misleading; the distortion LPs convey is much lower than you seem to realize. For example, the cutter amplifiers used to drive a cutter head usually are spec'ed to make about 10x the power needed to completely fry the cutter head itself (obviously this means that the mastering engineer has to be quite careful as the cutter head is thus very easily toasted). In essence, the cutter amps are/were loafing in order to make any cut ever put on a stereo LP. The problem with LPs is not built-in to the LP itself as it is the often poor setup that occurs in playback (which is not the fault of the LP) and also the much higher distortion that occurs if analog tape is in the equation. So I am making a distinction between the capabilities of LP as opposed to the tapes that are often used in making them.

Competent digital converters (ie: CD quality at 16/44) have typical distortion less than 0.01 percent at all audible frequencies right up to the point of hard clipping. I'll be glad to see your real world distortion numbers for sine waves on an LP played back at typical levels. Use the best test tone LP you can find, with the finest turntable and cartridge you can get your hands on, and have Michael Fremer align it if you'd like. :->) I imagine that best case it's at least 100 times worse than the distortion of CDs but, as always, I'm willing to change my opinion as soon as you or someone else shows actual evidence. So whatcha got?

When you say "0.01" are you referring to THD? When one looks at digital specs, one is lucky to find the distortion spec listed at all; if it is its usually in terms of db and at that also as a composite figure representing THD and noise together (which seems a reasonable way to express the value). However its the inharmonic distortions that are the larger amount of distortion that has shown up in a lot of digital gear over time, but that number is not included in the spec, in fact I don't see it on websites anywhere. The industry as a whole seems reluctant to produce specs on it, but especially in the old days it was the primary distortion component by a large margin. This to me is one of the annoying things about the industry; many of the specs are made for marketing purposes.

So until we can get a handle on that I don't think we can pass judgment one way or the other.

So it's disingenuous to pick on that one situation when it's clear that the real BS is selling "isolation products" for use under wires and CD players etc.

Since the collection of data from a CD is an analog process, its reasonable to assume that reducing vibration in the transport will improve data recovery. Its not uncommon to see damping applied to high end CD transports. I for one am happy to see other codices supplant the CD.  

I've seen situations where cables have been microphonic (for lack of a better word). I've seen microphone cables 'squeak' when disturbed (although depending on the cable that can vary by quite a lot) and I've seen longer interconnects between an amp and preamp do the same thing (although to a far lessor degree). I personally feel when a cable imparts an artifact like that when moved that maybe one might want to find a different cable, but I can imagine others using little stands and the like.

I put myself through college and the like by servicing consumer gear. I have seen microphonic transistors and ICs (that simply had to be replaced). Semiconductors are not entirely immune to vibration, but I expect that the equipment under test would have to be mounted on a shaker table to see anything significant.

However, some types of capacitors are much more susceptible, and these types are found in both tube and solid state equipment. In addition to the ceramic devices in the article link below, silver mica, tantalum and mylar can be added to the list although they don't react as much as the common disk cap. Its a short article, and may explain why the conversation continues with the equipment stands, even though tubes and turntables are not involved (BTW this was a first hit on Google...).

https://e2e.ti.com/blogs_/b/precisionhub/archive/2014/12/19/stress-induced-outbursts-microphonics-in...

If there was some mysterious type of "inharmonic" distortion, other than IMD or jitter or aliasing which are all known and understood, I’d have seen it by now in an FFT. There is no such thing. If you believe otherwise, please post an FFT showing that distortion, and explain how you created it.

Thanks for your explanation. So the specs you quote are from your own measurement?

Inharmonic distortion is a form of IMD, in this case related to the scan frequency. Its called that as the distortions are not related to harmonics of fundamentals, and differs from regular IMD as it can occur with only a single tone being recorded. IME, its most likely to show up on the record side, and can’t be detected with static tones. You have to use an analog sweep generator (using static tones, or tones generated digitally allows the technician to be unaware that there might be a problem). Set to sweep 20-20KHz, record at just below 0VU and in playback, listen for the ’birdies’ (this is radio parlance for subtones and supertones that vary with the changing frequency of the sweep tone; obviously you will want to set the speed of the sweep to a slow rate so its easier to experience the birdies). It might be a record-only artifact; the problem is you have to play back the sound file at some point and I’ve not investigated the issue enough to ascertain how much of a role the playback systems play. This problem seems to have improved over time- it was horrendous only 15 years ago!

First, the makers of "high end" CD players do whatever they think is needed to convince people to pay handsomely for their stuff. That they "isolate" their transports means nothing. They probably claim to use some BS over-designed power supply too. More important, if you believe normal amounts of vibration can affect audio quality, why don’t you test it for yourself? I’ve done that, which is why I know isolation for CD players is BS. It’s not a difficult test! If you design audio gear, surely you have a sine wave generator, a CD burner, and a way to record the player’s output as you shake it around while playing your test tone CD. Or just watch the output on a ’scope as you shake it. Or just listen. Sheesh!

I do design audio gear, but never gotten to the point where I take digital seriously. I show with digital gear at shows of course, but if I have the same track on LP its always a very easy thing to demonstrate how much better the LP sounds than the digital. The worst system we’ve used at shows was a Tascam DV-50; Tascam is a major supplier of CD transports so you would think their machine would be pretty competent, but I found it irritating enough that usually I could not play an entire track with it (and I have found this pretty repeatable with other examples so I know it was not due to a malfunction). By contrast I find the less expensive Oppo players to be more musical.

The way I see it, if digital is working properly you won’t hear any difference from one machine to another, but we hear differences all the time, which says that the digital is falling well short of the ideal.

The most expensive setup we’ve shown with was also the best (although a close runners up is much more affordable!) by a country mile over any setup I’ve heard anywhere (I have customers with the dcs setups, which have been a benchmark in high end for a long time). When the designer was in the room playing a cut, I asked him if he would like to hear the same thing on LP; he said yes and upon hearing the difference, turned to me and said "digital has such a long ways to go". Its that pragmatic approach on his part which I credit for his gear being one of the very best I’ve seen.

Now I should make a distinction here- if the sound file is stored on a hard drive or the like I find it robust. It should not be that when you change a CD transport that the sound should change but it does. That simply says to me that CD playback is variable, and is a proven topic that has endured for decades on the web. In a nutshell, its not robust while hard drive performance is. This is why there are programs like ’CD Paranoia’ (an older bit of software for Linux) because Redbook simply does not allow for complete data recovery.

Its very easy to show that vibration can affect a CD transport. Just tapping some machines can cause the CD to drop out or stop playing altogether! So it would appear that reducing vibration, such as on a platform, could have an effect. Personally I feel that the sooner we get rid of the CD format, the better.

LOLZ. I’m surprised it took you so long to delete my post. Though it was totally deserved. But you didn’t ban me from the forum? What’s wrong with you peeps? Seriously, what’s wrong with you? :->)

What's wrong with a lot of people on this forum is they really seem like they want to push audio as far as possible- to find out how real they can make it sound (its that bit of intention that separates high end audio from mid-fi). There are a lot of opinions as a result. Sometimes there are facts too.

FWIW none of the people on this thread are moderators. The moderators seem to operate without involvement.

Ethan, if I can offer some advice and comments: First, I respect your knowledge of room treatment and for the most part, how digital works (I think is safe to say we differ as to how well it succeeds over the prior art).

The first bit of advice is this: no matter how much you know, there is always something more. If we look at all the knowledge in the universe as a pie, what we know is a tiny sliver. What we don't know and also at the same time know that we don't know it is a much larger bit. But by far the lion's share is the part where we don't know it and don't know that we don't know. That's well over 99%, and that's that part that acts as blind spots in our lives. Obviously this applies to far more than engineering!

The second bit of advice is (and I have lived this part since about 1988 or so, when everything was line command): You are far better off allowing someone else to defend you than doing it yourself. But in order for that to happen, you have to earn the respect of others. Its not easy on the web! We tend to say things that we would never say in person, and the fact of the matter is there is a live person behind each keyboard, and you don't get their respect by abusing them.

Now it happens that you and I are likely on the same page with a number of issues. From what I can make out, more than where we differ. I think the big area that we seem to differ (and this is based only on my prior experience dealing with you in the past) is that I tend to hold the viewpoint that there is still a lot that we don't know about audio (I'm of the opinion that its possible to be far more rigorous with testing than we are currently and also that the industry ignores physiological information about how we perceive sound and so is about 40 years behind as a result), whereas (and I do not mean this in any insulting way and for that matter could be dead wrong) it seems to me that you feel that everything we need to know about audio is already known and has been known for some time. Now I only say that because I've seen a number of people in the past that claim to be 'engineers' who seem to have values and attitudes very much like yours, but it could be a lack of understanding on my part so please correct me if I'm wrong.

Ralph, I absolutely do not think I know everything. I do think that everything that affects audio fidelity is known, and so there’s no mystery, but I know very well that I don’t know everything. A list of just what I know that I don’t know would be pretty long. Then there's the stuff I don't even know that I don't know. That said, if you think people like cockrum and kait have anything to offer that will increase my knowledge of audio, I have a bridge to sell you in Brooklyn.

Regarding kait, I invite you to reread some of my prior comments that were directed at you; you should already know I don't take him seriously.

OK- so where we really differ is that I know for a fact that 'everything that affects audio fidelity is known' can't possibly be incorrect. Its an attitude I've run into before and I always find it puzzling, as it should be obvious that it causes the holder of that attitude to not know what they don't know.

I found out a long time ago that when I think I know everything that is why I'm most likely to screw up.

While I do agree that most of the technical stuff seems to be well understood, occasionally I run into things about which the current paradigm doesn't seem have any knowledge. This is why I hold a couple of patents.

In fact I'll take that a step further, if

everything that affects audio fidelity is known

then innovation would be impossible; inevitably a person with that attitude will find themselves on the wrong side of history so to speak.

One area of interest to me is the physiology of human hearing (**not** psychology, just to be clear); IOW how sound is perceived by the human ear/brain system.  There has been a lot in that field that has only been figured out in the last 30 years or so, and some of it only in the last 10 years. But the test and measurement concepts employed by the audio industry are based on our understanding of how the ear/brain system worked from 60-70 years ago. And even 'way back then, some of what was known got ignored by the audio industry (although Norman Crowhurst made inroads in that regard).

My conclusion is that equipment that sounds correct to the human ear does so because it follows those rules of human hearing more closely than equipment that does not. This is not a big step to understand! But the simple fact is that most audio equipment (about 99%; includes your Pioneer receiver) violates one of the fundamental rules of how the ear perceives sound (how we interpret sound pressure). This fact was understood by the mid 1960s but the industry has chosen to ignore it because it was inconvenient.

Its disparities like this which is why there is the objectivist/subjectivist debate (and why this thread is as long as it is...). If the audio industry measured the right things then there would be no room for that debate.

This is why I say that the industry is about 40 years behind where it should be. It appears also that the only progress that occurs as a result is in high end audio (and I freely acknowledge that high end audio has a good deal of charlatans as well).  

For the record, I usually find myself on opposite sides of a debate when kait is involved.

I’ll email you about my project because I imagine you’ll find it interesting. And maybe you’ll be around for a phone call over the holiday "dead" week between Xmas and New Years? I'm sure we do in fact agree on 90+ percent of this stuff!

I'm usually around- quite often that is our busiest week of the year.

I am familiar with the nulling technique- hard to get through school without knowing that. I am skeptical that the test will have the resolution required but I suspect that will have a lot to do with what exactly is being tested.

A customer of mine liked to replace parts in the power supplies of his equipment. In order to know if he made any progress he placed a microphone in his room at the listening chair and then ran sweeps and distortion tests, and compared them to 'before' and 'after'. He was thus able to document what he heard.

But what that argument misses is whenever you have THD you also have IMD.

This statement is a bit misleading but is not false. The problem here is that there is often an idea that if you have high THD you must also have high IMD and that is the part that is not true. You can have low IMD figures and still have a fair amount of THD. I refer you to the specs of our amps on our website. THD is excellent for a zero feedback amp (0.5% is typical) while IMD is lower by an order of magnitude or more.

There are of course cases where IMD is higher, especially in older tube gear, but its important to understand how IMD arises, and IME that has a lot to do with power supplies which are a weakness in older tube gear (an exception being vintage Futterman OTLs which have very respectable distortion figures).

Since we felt that loop feedback was a poor option for reducing distortion (results in higher ordered harmonics), we avoided IMD by employing a separate power supply for our driver circuits, so that any perturbations in the output section could not affect the driver. We also reduced it by making sure that the timing constants in our power supplies were in fact lower than those of the amplifier circuit itself. Finally, we made sure that any fixed bias points could not be modulated by the audio signal itself. Vintage tube gear does not do these things (and also tends to have transformers...)! As well any solid state amp that is direct-coupled input to output is also at risk unless its powered by a battery. That is why battery-powered transistor amps tend to sound better (its hard to measure the difference in IMD in those cases, but the ear is well-known to be pretty sensitive to IMD as you know).

FWIW, IMD is really well-known to not be pleasant to the ear and is **not** the reason people prefer analog or tubes (which generally **are** pleasant to the human ear)! So right here your argument seems to fall apart, as you seem to be conflating IMD with THD. THD is its own issue, as you know transistor amps are pretty low in THD, but what they have of it happens to be highly audible and objectionable to the human ear. Yet about 95% of all analog recordings are done with solid state, so I’m still having a problem with the way your argument is stated. I think you are missing something.

’Clarity’ as in ’music less clear’ is not a spec on any bit of paper. Its something ***Subjective***. And I do agree that higher IMD impedes clarity as well as altering the tonality towards brightness (because the ear converts IMD to tonality as well).

As I have pointed out before, digital systems have a form of IMD known as ’inharmonic distortion’ as it is intermodulations unrelated to fundamental tones. I think you must not believe that it exists; I’m pretty sure that your response to that idea resulted in a post deletion. I could be wrong. But its a thing I’ve experienced myself with a simple sweep generator, so I know its real and I know it exists in modern digital gear too. I don’t really care whether its in playback or record- you can’t playback if you don’t record (that’s an existential thing....).

What I think you are missing here is what I have stated before- which is that if the ear is very sensitive to the distortion, that even if on the bench that distortion **seems** low by bench measurement standards such as you are accustomed, its still quite high! The industry still struggles to measure these distortions accurately as they tend to be ’buried in the noise’ which is often a convenient excuse while at the same time not accurate. Our testing needs to be more rigorous.

The proof of this is that tubes and vinyl are still very much around and not dependent in any way on the high end audio community. The year of least vinyl production was nearly 25 years ago!! There are now more manufacturers of tube equipment in the US than there was in 1958. Think about that- the market wants it, and its not likely because its distorted. You ask a kid (and I have many times as I play in a band and do local shows) why they prefer vinyl and they’ll tell you because it sounds better. That’s not someone preferring distortion- because the ear isn’t sensitive to the distortion that the bench measures so much as it far more sensitive to the types we struggle to measure! I am repeating myself because I’m trying to put this in several ways so you can understand what I’m trying to say and yet make it understandable for the layman.

The very definition of high fidelity is a flat response and low distortion. Yes, many fabulous recordings have been made on old school analog equipment. But that equipment has lower fidelity than even consumer-grade modern digital converters.

Ethan, when you say that a person 'prefers distortion' I assume that you know that the ear/brain system converts distortion (unless outright, as in clipping) into tonality. This is why a lot of tube equipment sounds 'warm' or 'rich', because of the presence of the 2nd harmonic. But this does not have to be made by tubes in particular, solid state can do that too (the early 70's Sunn solid state instrument amplifiers are good examples, as is the old AR amplifier). Much also depends on topology.

For example, you can prevent tubes from having a 2nd harmonic simply by employing fully differential design from input to output (which is how a lot of transistor gear is designed).

Regardless, the admonishment I am offering here is to be careful about attempting to place all the 'deplorables' in one basket! The issue is that the human ear/brain system is relatively insensitive to lower ordered harmonics (2nd, 3rd and 4th) while it is **very** sensitive to higher ordered harmonics- so much so that it can detect them when often test equipment cannot. The reason for this has to do with evolution and the fact that our ears use higher ordered harmonics in order to gauge sound pressure (this fact was first documented by General Electric about 1965) and is very easy to prove with very simple test equipment (I have documented how elsewhere on this site).

So if the ear is insensitive to a certain distortion, does that mean that if that distortion is present in a given bit of equipment, that it is heavily distorted or not? This refers to a comment I made earlier where I mentioned that the audio industry tends to be about 40 years behind where it should be because for the most part it ignores how our ear/brain systems perceive sound. Certainly our ability to detect sound pressure has to be one of that more important aspects of that perception!

So where I'm going with this is that just because analog systems have more distortion to which the ear is relatively insensitive, that is not saying the same as its 'less high fi' when the succeeding art tends to have **more** of the types of distortion to which the ear is far more sensitive! In essence, as far as I can make out, digital fails because generally, while having lower distortion on paper, in practice that distortion is far more audible to the ear (which is converting it to tonality). And since this is all about stuff we hear rather than what we see on a bit of paper, I don't think its correct to say that analog is less 'hifi'.

What is more accurate is to say that analog, despite having greater distortion, more closely follows the rules of human hearing than does our current state of digital. BTW this is also true of tubes (and certain transistors) as opposed to transistors in general.

I get that it takes a bit to get your head around that 2nd to last paragraph! If you look at how stuff measures on paper, in essence the wrong things are being measured. So as a result, if the paper spec is your guide, you miss something.

This is why there is an objectivist/subjectivist debate, a tube/transistor debate and an analog/digital debate.

BTW I do not regard myself as a subjectivist- I'm an objectivist (if such a thing is really possible- philosophers will tell you that it is not) that feels that to ignore aspects of our hearing that our testing ignores is not wise.

This is why tubes and analog are still around. The market keeps it for a reason, and high end audiophiles are not that reason! They represent a tiny portion of the marketplace that keeps this stuff alive.

Digital systems do have aliasing, and that's like IMD except one of the source frequencies is the sample rate. So you can get aliasing with only a single pure tone. I guess you could call is inharmonic distortion but I'd rather call it what it is: aliasing.

Thank-you. 

The problem is if you call it aliasing without acknowledging that its also distortion, it leads to confusion (if there is IMD or THD, they make artifacts not found in the original signal, why should aliasing catch a break?).  Distortion is really the more accurate term. And its so audible that in the old days it was criminal. No analog system ever had artifacts like that (unless is was badly malfunctioning)!

So I think you can see that I regard calling it 'aliasing' without also speccing it as a distortion is disingenuous. Its simply a way of hiding a rather serious artifact and hoping no-one will notice. But it did get noticed and is why the LP is still very much alive today!

So, if you **include** aliasing artifacts in with the THD spec of a typical digital system, what does that number look like?

But isn’t AES actually an anti audiophile organization?

Seems to me Stanley Lipshitz first presented his formulae on creating RIAA EQ curves to the AES. They also have that File 48 (balanced line standard) I like to trot out.  Baby and the bathwater...

ah, so it's a mix of science and anti audiophile conservative dogma?

You take the good with the bad. Like any organization that has people in it, its going to have politics and outright flimflam. No-one's perfect. But their goal is good engineering, and often they succeed. But if you deal with them you have to expect to do some wading, just like you do here or anywhere else.

Ralph, aliasing should be included within a typical "THD plus noise" spec, and I see no reason to call it out separately. Harmonic, inharmonic, IMO it’s okay for all artifacts to be lumped together. If the sum of them all is below 80-90 dB, none of it will ever be heard anyway. With a typical converter the sum of all artifacts is well below 100 or even 110 dB.

OK- we’re on the same page, except for one thing. And that is that if the artifacts are at -80 or 90 db, that’s no guarantee that they can’t be heard!!

You have to understand that the rules of human hearing have to be the number one thing in audio. But the industry in generally usually finds them a bit inconvenient.

This is an example:
Even if the artifacts are really down that far (and I question that as aliasing is really best detected with an analog-sourced sweep tone, and further just because a DAC is pretty good at it has nothing to do with how good the ADC was- and without the ADC you’ve got no software....), the human ear uses higher-ordered harmonics to calculate loudness. In addition, the ears are tuned to be most sensitive at bird-song frequencies (and aliasing produces ’birdies’ all the time), meaning that the artifacts can be that low and yet easily detected.

Of course we won’t hear the artifacts as they are- the ear converts them to tonality.

This is why there is a digital/analog debate!!

Many people object to the ’brightness’ or ’hardness’ of digital as opposed to analog, and there is no way that such can’t be interpreted as a **coloration**.

There has been an analog/digital debate going back to the early 1980s and you’re looking right at the reason in this post. When you have a coloration like that, there is no way it can be considered neutral and ridding digital of this problem is the cutting edge of where real advancements in the digital art are being made. The thing is, the distortions of analog are less audible to the human ear, and so even if on the bench they **appear** larger, in reality (because our ears are the reality, not the bit of paper) they are in fact **smaller**!

If you don’t understand how human hearing perceptual rules work, you will have trouble understanding how this is so. Think of it in a logarithmic fashion, but instead of being related to sound pressure (decibels), its instead related to higher ordered harmonics and intermodulations.

This is why I have been harping about the fact that our understanding of how human perceptual rules work is where the big advances in audio are occurring, and why it is that as an industry we fall well short of knowing all that should be known for **real** high fidelity. This is why high end audio exists, to plumb these issues and offer solutions, since mid-fi is only dollar-oriented and has to be pushed pretty hard to change. Of course, some high end audio things don’t work because in a way many of us are stumbling around in the dark due to the industry’s overall lack of interest in human hearing perceptual rules!

Because things like equipment stands can reduce tiny amounts of microphonics and other HF artifacts, they have a value; this is due to how our ears work- and I concede that the differences can be hard to measure because our test equipment lacks the required sensitivity that our ears easily have. There are many things where our ears are less sensitive than test gear; higher ordered artifacts just happen to be an exception.

Have you ever done tests like this? I have, many times. I wish more people would! Here’s one that plays a very nasty harsh noise under gentle classical music, and then under a synthesizer based pop tune:

http://ethanwiner.com/audibility.html

I first looked at that link 2-3 years ago.

IMO/IME, this is a good example of testing for the wrong thing!!

Done as this test is, it does not reveal the problem. I agree (obviously) that you don't hear the artifacts (**as I stated in my post above**); what you **do** hear is that the sound is brighter and harder than the source, because the ear/brain system converts the "inaudible" artifacts into tonality.

Because the tonality is caused by the ear's perception and not an actual FR error, it does not show up on the bench. Hence the objectivist/subjectivist debate and the need to understand how the ear works.

I'm not sure if you understand this, but its the tonality and the accompanying hardness to which audiophiles object.

Hey wait, I have an idea! Tell me if you agree before I spend the hour or so this will take: I'll prepare clips of the same two examples in my Audibility article, but they'll be longer and I won't tell you there the nasty noise starts and stops. I'll put them on my site and post the links, then you'll play the clips and tell me where you think the noise is present. Then I'll tell you if you're correct or not. If you fear I'd lie about the locations, I'll be glad to email the answers in advance to a disinterested third party. Deal?

Here's the problem with that!
First:
That test is not testing for the problem. Its essentially demonstrating the ear's masking principle. All this time, I've been talking about something else.

Second:
I've worked really hard to make sure my gear lacks the higher ordered artifacts that cause brightness. As a result, even at 100db my system has a relaxed presentation (it doesn't sound loud- you don't realize how loud its actually playing until you try to talk to someone right beside you).

Part of what makes that possible is to not give it a source that is inherently messed up! When you post a sound file, its **digital**. Once its in whatever codex, the associated artifacts that allowed it to get there are inherent in the file- no matter how good the intentions. Once there, they can't be removed. this makes it unsuitable for the caparisons I would want to demonstrate.

An alternative would be to encode the material on an analog format, so the artifacts in question aren't inherent and instead are added. I'm betting that's not going to happen.

An additional problem- the one with going to your house- is that in doing so, the test has to be heard through gear that is known to contribute similar artifacts. This makes it tricky to make any sense of the results and I'm pretty sure is part of why you've already seen null results.

BTW Ralph, you don’t have to keep saying stuff like "You don’t seem to understand." I’m certain there’s much here that you don’t understand, but I don’t feel the need to insult you by using such language.

I was attempting to pin you down on a point, which you've sidestepped pretty consistently. That suggests to me that its possible that you've not dealt with the topic before. "you don't seem to understand" is a shorthand way of conveying that; please note the word 'seems' that I was careful to include in that phrase and it was in no way intended to be insulting.

Put another way, you freely acknowledge that analog and tubes have artifacts that cause them to be 'warm' (while measuring perfectly flat on the bench) but so far you don't seem able to also acknowledge that transistors and digital also have artifacts but of a different nature that cause the aspect of 'brightness' and 'hardness' which are also colorations. This too suggests a lack of understanding, but it might simply be a reluctance to cede the point.

FWIW, the fact that trace amounts of the 7th order causes a metallic quality in the sound is something that has been known since the 1930s. So I don't see it as any stretch at all to simply acknowledge that such could be the case. I really don't want to devote more time going round and round on the topic than you do.

At any rate y'all, (including you, Ethan), Enjoy the holidays!

But really, your claim is disingenuous on its face. All my Artifact Audibility test attempts to show is at what level below music a nasty sounding artifact can be heard. It has nothing to do with digital always adding disturbing artifacts, or whatever it is you believe. If that were even true, those artifacts would show up when recording and playing back a pure sine wave, or some other known source. So already your claim is easily proven false using basic audio test equipment. I should have posted this link earlier:

What your Artifact test does is demonstrate the masking principle. It does not get at the issue of how artifacts introduce coloration by adding brightness. It does very effectively show how a sound that's 40 db down (or even less) might not be audible when louder sounds are present.

I think I have a Nakamichi machine still laying around somewhere. I would need refurbishing though. Most of the rubber bits have perished.

Here is the problem: When you are demonstrating an artifact like the effect of aliasing (which should be inherent in your digital gear) you can't use the same gear to show 'with' and 'without'; that won't work since it would always be 'with'.

Distortion (including aliasing or inharmonic distortion) is a bit insidious as there is this assumption that the distortion artifacts are masked or buried in the noise. Sometimes this is true (certain harmonics can mask the presence of other harmonics) but the ear has a way of allowing us to pick out very low distortion artifacts not by detecting them as themselves, but by converting them to tonality. In a way they ride on top of the signal rather than at the bottom (metaphorically speaking). So what we would be looking for in a test is to see which is brighter (without actual FR errors being introduced).

This, Ethan, is why I've been wondering if you don't 'get it'; your responses to me have all been about masking, which is something other, and something I don't contest (masking being an important rule of human hearing). Perhaps it might help to know that in the last ten years, Dr. Herbert Melcher has shown that the human ear/brain system has tipping points. An example of that is if the playback has insufficient speed (risetime) the brain has a tipping point where the music processing is transferred from the limbic centers to the cerebral cortex.

Another example of a tipping point is where the brain will favor distortion as tonality over actual FR errors! Now both of these things were not known back in the 1970s and are examples of 'now that we know that, we can do proper engineering to take them into account.'

So in a case where we want to demonstrate aliasing, or how the presence of trace amounts of higher ordered harmonic distortion can be detected without hearing the actual tones, its likely that the test would be constructed on a platform that first is immune to the problem itself, so that the problem can be demonstrated. Then once that is done what we are looking for is tonal differences between the two examples 'with' and 'without'.

You can see right away the difficulty! To demonstrate aliasing, it can't be done on a digital system since aliasing is inherent; to demonstrate higher ordered harmonics you can't have them inherent in the system which probably means no transistors in the signal path. 

Atmasphere help me understand the artifacts you talk about. Is this related to the fact that human hearing is not flat but more sensitive at certain frequencies as shown here or something else?

It does matter that our ears are tuned to bird song frequencies (IOW Fletcher-Munson); this is the result of evolution as birds are the early warning system of the presence of a predator in the environment. You can regard this extra sensitivity as a complication!

But its more than that- the ear/brain system converts distortion to tonality. This is why one amp can sound bright while another does not, even though while on the bench both amps measure flat. The difference is that the former has more higher-ordered harmonic distortion and so sounds bright despite being perfectly flat in bandwidth. 

Seventh harmonic causing a metallic quality: I've heard that several places, but in this case the easiest to remember is John Curl (one of the top solid state designers alive today).
https://www.youtube.com/watch?v=fZwS-oyqc3w

goto about 36:35

Ralph, I read your posts several times. You didn’t describe a test you’re willing to take. Rather, you wasted several paragraph explaining why it’s impossible to devise such a test: Your cassette deck needs new rollers, a special platform must be constructed, and - most incredible of all - you can’t demonstrate digital aliasing on a digital system. :->) What a waste of both your time and mine this has been.

Actually I did. I said (again) that it would have to be on a system that lacked the artifacts under test. So to test aliasing, it would be on a system that is immune to such (an analog system). To test for higher ordered harmonics, on a system that lacks said (likely tubes). The test would be the same track, one ’with’ then the same ’without’.

I can easily make a recording of the 'with' and 'without problem of aliasing.

Your belief that distortion is different from "artifacts" and so can be heard at infinitesimally small levels is preposterous. I challenge you to prove it. Hint: you can’t because it’s not true. And your other belief, that distortion "brightness" is different from frequency response brightness, is equally preposterous. If you change the spectrum, how and why it changed is irrelevant. If you add 10 percent 3rd harmonic distortion to a 1 KHz triangle wave, that’s exactly the same as boosting an EQ by about 1 dB at 3 KHz.

Proof: analog and tubes are still very much alive, decades on after being declared ’obsolete’ (the market knows what’s up even if you don’t). But that’s not all: tubes/transistors debate (and the complaint against transistors is ***brightness***, when clearly there is no FR error, as I have explained....); the analog digital debate (again: brightness is the coloration...). Both of these debates are older than the web. And distortion is at the root of both of them. You **know** this!

In case its not clear, all audio products make distortion and all audio products have a coloration as a result. So even in this day and age its still all about the distortion.

The 3rd harmonic is not an example as I’m sure you knew when you wrote that. I’ve been careful to say ’higher ordered harmonics’, which are the 5th and above (the ear being relatively insensitive to the lower orders, the 2nd, 3rd and 4th). Your comment fits the definition of a Strawman to a ’T’.

Adding 0.05% of the 7th wouldn’t even show up in a FR analysis- but its easily heard. Go back to that link of John Curl:

https://www.youtube.com/watch?v=fZwS-oyqc3w

The book he refers to is the RadioTron Designer’s Handbook, a reference tome known to many. I have both the 1941 and 1953 editions (the latter is the red one). If you think you can make a better amp than he or Nelson Pass (or Charlie Hanson, IMO responsible for one of the other great solid state designs), let’s see you get out there and do it.

Again this is such basic stuff that I now have my answer: You do know that what you’re claiming is nonsense, but you do it anyway to sell stuff. So I’m pretty well done here, though I still look forward to your proof that distortion is always audible even when it’s 80+ dB below the music.

Apparently I was right that you don’t seem to understand why its important to get rid of distortion. If what you say were true, 10% would be unimportant as you would never hear it (by your way of thinking, your masking demo shows that in spades)! But its obvious that isn’t the case and you confirm that by insisting as I do that distortion should be low. The contradiction is obvious. I am currently of the impression that you are so intent on making me wrong that you don’t care if you contradict yourself.

I suggest once again that you read Norman Crowhurst.

http://www.tubebooks.org/technical_books_online.htm

Remember what I said about blind spots? This is an example of something where you act like you don’t seem to know, and you act like you don’t seem to know that you don’t know it. That was why I brought it up the first time and your posts have very consistently proven me correct.

Ralph, this is very simple, and you have danced around it repeatedly:

If the "digital" artifacts you refer to are loud enough to be audible, then how come they don't show up in a standard FFT measurement? Or in a standard THD test that nulls the test frequency and leaves everything else. You already agreed that stuff 40-80 dB down is too soft to hear when it starts and stops in my Artifact Audibility test, so by extension it's too soft to influence "tonality" either. Aliasing, and all the other bugaboos you talk about, are 100+ dB down. And so they are inaudible. This is very simple audio basics, and clearly the burden of proof is on you to prove otherwise. Since you still haven't described a test you're willing to take that will let you prove your beliefs, it's clear that you're unable to do so.

Here's direct question I hope you'll answer: Since you are unable to prove your beliefs, I can only assume you haven't proven them to yourself either. So doesn't it make sense for you to do some experiments, so you will know that your beliefs are valid? I'll be glad to hear how you would test yourself!

Actuallly Ethan we must be talking past each other. I feel also that you've not been addressing my points, and when I stated that you didn't seem to understand, you objected but nothing happened. I've answered your question in the second paragraph about 5 times now! So I have to assume that my assertion was correct- you really don't get it! Let's start with this one:

you already agreed that stuff 40-80 dB down is too soft to hear when it starts and stops in my Artifact Audibility test, so by extension it's too soft to influence "tonality" either.

This statement is false and describes a basic misunderstanding of how distortion interacts with the ear (much of which has been known since the 1930s). Because of the masking principle, louder sounds make it difficult or impossible to hear quieter sounds. But distortion is different from sounds buried in the mix. In a way it rides on top of everything else and so is **always** audible. Again, this understanding has been with us since the 1930s. The way you seem to be looking at it is that somehow distortion gets buried under that rest of the signal, especially if its a loud one. If that were true we would not need to bother with the distortion spec of an amplifier at full power as it would be irrelevant! Clearly it is not.

Since you still haven't described a test you're willing to take that will let you prove your beliefs, it's clear that you're unable to do so.

I've described a test at least three times now. Please go back and reread my comments.

Here's direct question I hope you'll answer: Since you are unable to prove your beliefs, I can only assume you haven't proven them to yourself either. So doesn't it make sense for you to do some experiments, so you will know that your beliefs are valid? I'll be glad to hear how you would test yourself!

This paragraph opens with a false assumption. When I first read the results of the GE study (mid 1960s) I set up some simple test equipment and was able to show easily that the ear is indeed far more sensitive to higher ordered harmonics. That and that they are unpleasant to the ear is no surprise- just listen to a square wave sometime.  Actually Ethan when it comes to challenging each other like this, I've seen occasions where you did not have measurements at your disposal (ex.: power cords) so I think its a little odd that you think I might not have sorted this stuff out for myself.  I suggest that you start by obtaining some documents and read them- the writings of Norman Crowhurst are immensely beneficial; if you're serious many of them can be downloaded from Pete Millet's website. Another nice tome to have on hand is the Radiotron Designer's Handbook (John Curl refers to it in the YT link I dropped earlier).

Its not peculiar that I think that the ear converts distortion into tonality **as you are suggesting** with the use of the word 'beliefs'. I've seen this before in skoftics (a term describing a person that seems skeptical, but when confronted will not examine the evidence as their position is based on belief and changing that belief is anathema to them), where they go so far as to contradict themselves as you are here in an attempt to make the other person in the conversation wrong.

By that I am pointing out that you admitted easily that a 2nd harmonic is easily audible as 'warmth'. So you allow for that, but you don't allow that other harmonics to which the ear is **far** more sensitive, can't be heard because they are at a lower level?

I have maintained that understanding of the physiology of how we perceive sound (in a nutshell, the rules of human hearing) is essential to progress in audio and is the arena of continuing advance in our field. From my perspective, your understanding of those rules seems stuck about the 1970s or so. A lot's gone down in the research of human physiology since then; if you were up on it we would not be having this conversation!

FWIW, two of the greatest solid state designers of our time are- John Curl and Nelson Pass. It should come as no surprise that they are responsible for some of the best-sounding solid state amps made.

whenever you have harmonic distortion (THD) you also have similar amounts of IM distortion (IMD).

This statement is misleading. You can have a fair amount of THD and still have relatively low IMD figures. This is however a very common saw and often it **happens** to be true; its just not true 100% of the time. 

And IM distortion is usually out of tune with the music, and so is much more audible and damaging than most forms of THD including the 7th harmonic.

This statement is true.

Chasing increasing small amounts of high-order THD in the presence of large quantities of IMD is like chasing unicorns.

The meaning here is unclear.

I doubt it, though I'll be glad to be proven wrong!

Cripes...

If you don't want to read through the whole thing, just scroll to the bottom

http://www.stereophile.com/content/lamm-ml22-monoblock-power-amplifier-measurements

Heck, I'll quote it:
(from Stereophile, measurements by John Aitkinson):

Whenever I measure one of Vladimir Lamm's amplifiers, I am always impressed by the quality of the engineering. Yes, the ML2.2 has a bent transfer function, which means that it produces higher-than-usual levels of second-harmonic distortion—but this is not accompanied by high levels of high-order intermodulation. And you have that low output impedance and very wide bandwidth!—John Atkinson

I did not add the emphasis on the word 'not'.

Sorry- but its pretty obvious you don't spend time with them, else we would not have been having much of this conversation.

I don't know what a "bent" transfer function is, but I'd need to know the specifics of the test. What frequencies, what levels, what amounts of each distortion type, and so forth. I know you can do the opposite: create more IMD than THD using a "full wave" multiplier. But anything that changes the waveform enough to add THD will add similar amounts of IMD. Not that John Atkinson is what I'd call a reliable audio reporter anyway.

Again your statement is false. You can have rather low IMD while THD might be ten times higher or more. Digital audio is a good example, as aliasing is a form of IMD, while THD is almost non-existent. You can't have it both ways!!

Instead of trying to make the world wrong why don't you read the article at the link instead of the innuendo? (BTW a bent transfer function is one that has a bend in the linearity curve) Its all there. I'm not a fan of John either (having nothing to do with his testing); if he makes a report on a test, then the test is pretty reliable (I caught him once on a bug in one of his tests, but the bug related to a design flaw in his test gear at the time, so that was understandable).

Again: Read Norman Crowhurst. This will give you a good grounding.

If you want to know how to build an amplifier (not that you do, this is academic) that can have low IMD while THD might be much higher, you have to start with zero feedback, and then sort out where the distortion sources are and reduce or eliminate them. Victor Lamm knows his stuff- very impressive specs for an SET.

So I just provided evidence, but you aren't interested. That is the definition of a skoftic which is very different from a skeptic.

JA and John Curl **are** evidence. Apparently you don't know the difference between evidence and proof. I think you are asking for proof but at the same time your website isn't that either. Any of your sound files can be doctored and there is no way a person going to your site has any way of knowing if they are the real thing or not. IOW, your site is 'evidence' as well, not proof. I also detect a bit of hubris- that somehow you place yourself above accepted masters in the field.

John Curl is not just evidence but proof in that his designs are well-recognized decades on.  Clearly he knows his stuff and he's been at if for decades. You're really going out on a limb trying to make me wrong by attempting to impugn John Curl!!

I recommend you get an oscilloscope and look at what waveforms look like. A 'scope allows you to do that- to view the same signals that might be driving an amplifier or loudspeaker. You can also view distorted waveforms on a scope and compare them to undistorted waveforms. I think you might already know this although your posts seem to belie it; so if you are looking at a distorted waveform, how can you tell? If you are able to answer that it might give you a clue as to why distortion is much more audible than you think.

One other thing: you are ignoring is how the ear works. It is far more sensitive than test equipment to higher ordered harmonics and there is a reason for that.  Again, an example of not knowing what you don't know. Without that understanding, I can see it would make it hard to see how the ear could detect distortion of only 0.005% or the like. I suggest you read up (perhaps set up that demo I posted earlier) and see for yourself.

There may have been shear wave interference when it was actually cut.

Interesting.  Can you elaborate on the last part of that statement?  Ralph (with your perfectly coifed hippy mane) care to add to that line of thinking?

Mane??

I cut my hair back about 5 or 6 years ago and joined the establishment. Now I quaff kombuchas while driving my Honda Insight and listening to NPR. I guess with that I'll never shed the hippy image.

How sad.  Do the Birkenstocks at least live on?

Heck, most hippies these days drive hybrids and drink kombuchas... but I've not had Birkenstocks for decades (they didn't hold up so well in the Minnesota winters; neither did my socks). But I still wear sandals as much as I can.

I even ride my bike with sandals (Shimano is making their clipless sandals again) which I used when I rode the Tour Divide back in June.

https://www.youtube.com/watch?v=jhrtPyr1KQI