Do we crave distortion?

[Travis]

• Nonlinear distortion: Added spectral contents to the signal (extras tones). Nonlinear distortions are hard to predict and cancel. Not very audible.

Edit: All sorts of modulation distortion like IMD or Doppler are nonlinear, before someone else brings them up as "other types".

There are many, probably the majority of published papers say the opposite with respect to IMD, it’s audible, and it’s significant in audio perception.

It appears to be one of the areas associated with low speaker design and measurements, there doesn’t appear to be a consensus among the science-audio engendering communities. I have read many papers from AES and Joirnal of Acoustics that have concluded on opposite ends of the debate. Here is a quick clip of what Klippel says about it (along with several papers published by AES):

Loudspeakers and other electro-acoustical transducers generate significant intermodulation distortions in the audio band which have a significant impact on the perceived sound quality. The inductance nonlinearity L(x) produces low harmonic distortions at low frequencies but generates wide-band intermodulation which rise to significant values (30 %) at higher frequencies. Intermodulation distortion can easily be detected by using a two-tone signal with varying frequencies of the excitation tones (“bass tone sweep” or “voice tone sweep”).

 

[solderdude]

Part of the non-linearity effect. Unavoidable, since the transfer curve isn't symmetric around DC.

Ah right... the odd distortion component..

It makes me wonder about distortion and perceived loudness. Could it be that the effect can be quite benign and flatter some of the recordings when they are reproduced on a transparent, also full range and low distortion system?

Or, to put it differently, if such tools are valid for music production to add some of the desirable effects to otherwise fully transparent production gear, wouldn't it make sense that reproduction gear doesn't need to alter it in any audible manner? Otherwise, a favorable combination then would be a kind of hit and miss, I would say.

To me, low distortion, be it in the recording or the playback system never seems too loud, so that's one point. Even good recordings of instruments with rich harmonic content.

Other than perceived loudness, if certain amount of distortion is already in the recording, I'm not sure about the required level of the added distortion profile to become just audible to me. When I tried Klippel test, it soon became quite obvious that it's not that audible at all if I want to just enjoy the music, or even in critical listening:

The interesting thing about the Klippel test is the small peak on the left. It shows that either people are lucky in guessing correctly or that there are a number of people that have good hearing, listen at a louder level and have a good music system.
It does, however, say nothing about a preference for low distortion.
The recording quality of that test is very, very poor b.t.w.

I find this thread fascinating.
One question I had is: What is distortion? Is it harmonics, or noise? What about a note that varies form the original? A C becomes a C minor. Broadly it would be a change from the original, a distorted version. What are the types of distortion?

There can be many types of distortion, For instance the dreaded crossover distortion in mal-adjusted class AB amps for instance hardly registers near full output power but is substantial at low levels and thus can be quite audible at lower and normal listening levels but the 'number' generated by measurement gear will not show any concerns.

Distortion is simply a deviation from the original signal expressed in percentage or level.
Note that all recordings already have 'distortion' added and all transducers also add distortion. More distortion at louder levels so is not a 'constant' number.

Some types of distortion are more audible than other types and some are more objectionable (sound quality degrading) than others.

What impact/significance of the THD and f his amps have on any of this.

Hypothetically, let’s say that ABX testing shows that for OP and the 10 tested, 0.2% H2 is the be all, end all number with the vast majority of classical recordings, or even all recordings. That’s the magic number.

We don't know because we don't know the statistics and the set distortion parameters have not been changed to lower or higher levels which may lead to more or less preference.
It is just an observation done by Keith with that particular setting of distort on his system.

Keith tested for preference, not audibility thresholds even though it is also about audibility thresholds this part was not included in this experiment.

Is that cumulative to the distortion that his amps are generating?

Yes, it is cumulative so also all present harmonics in the recording get extra harmonics added (just 0.2% though) and the amp itself adds some to those numbers and then the speaker also adds harmonics (mostly 2nd harmonic and at higher levels also odd and doppler).

In other words, if there were such a magic number, does it still work with average SINAD rated amps, and the best SINAD related amps? That the number will vary, more for lower distortion amps, less or none with high distortion amps?

Yes, it will also add with low SINAD amps as that number only says something near full power and at 1kHz only and includes noise.

Something I've wondered about, but don't have the training to answer.

1. How much of an Amps available power is consumed when it has to "amplify" non-audible and (relatively) high-level 2nd, 3rd and 4th order harmonics?
2. Can the "diversion" (for a lack of a better word) of an Amps available power, in the amplification of non-audible distortion, impact the sound of the audible spectrum?

1: In this particular case (0.2%) distortion is added so roughly 0.2% more power is delivered to the speakers. So if a peak would be 12V in 8ohm (18W) then the peak would become 12.024V = 18.07W
As you can see the impact of added distortion at this level is not substantial in any way.

There is no perceptual model for distortion.

yep.
Frequency, masking, distortion type, recording and playback level dependent are just one of the variables.

A single number measured at a specific level only tells us 'something' but not the whole story nor audibility in all circumstances. Several types of plots already tells us a bit more, certainly when done at various levels circumstances.

 

[Travis]

1: In this particular case (0.2%) distortion is added so roughly 0.2% more power is delivered to the speakers. So if a peak would be 12V in 8ohm (18W) then the peak would become 12.024V = 18.07W
As you can see the impact of added distortion at this level is not substantial in any way.

Thanks for answering my questions, and these others. I had a feeling this would be a very interesting thread and thus far that has been the case for me.

I don’t know what the ultimate takeaway of all of this is, but it helps me to understand MAYBE that someone who goes from higher distortion tube amps for example to something like Benchmark, hears a difference (my case) hears a difference.

Fooling around with blind tests I had a preference for the tube amps, for about 3 months, listening everyday, then more blind tests much later on with friends that was strictly music dependent. It just depended on the track, but just a very slight preference.

So when I saw the first post it obviously triggered a lot of questions in my mind, like could this be related in some way to my experiences in blind tests to hearing a difference between a SET amp, and very well measuring SS, preferences, change in preference, etc.

Many responses here have helped me exclude some hypotheses I had, and others have clued me in on ones to follow up on. I haven’t reached any conclusions on what I experienced, but it has me in a direction to follow up with with certain things. I think this was the spirit of what the OP intended (but from a slightly different angle). As with a lot of things in this Forum, there are bits and pieces that have been been discussed in previous threads, but it was nice to have it all here together. To the extent that I have drug this thread off of his original specific purpose to try and answer some of my own questions, I apologize to him and the rest of you.

Looking forward to seeing additional contributions here.

Just wanted to say thank you to all who responded in this thread and took the time to locate and post studies/papers. I find that I learn something from every paper, whether I agree or not (because of other papers, etc.).

This continues to be a great example that in the perception of Audio, and audio reproduction, there are a great number of moving parts (variables) and there frequently isn’t a simple answer.

Do we crave distortion? Some may, and there is a reason, but probably an overstatement.

Do we prefer added distortion? It depends, some do, and there are many examples in many contests, but, for me, jury is out and will do my own blind tests with the software as suggested by the OP when I figure out what I need to use the plug-in .

 

[pseudoid]

...Do we crave distortion? Some may, and there is a reason, but probably an overstatement.

Do we prefer added distortion? It depends, some do, and there are many examples in many contests, but, for me, jury is out and will do my own blind tests with the software as suggested by the OP when I figure out what I need to use the plug-in .

Great synopsis.
Maybe we all need to get with the current lingo and call such possible distortion-pleasures (<< wutevr form they maybe >>) "micro-dosing"!
I have always gotten the heebie-jeebies [?] when injection of superfluous signals (e.g. distortion/noise/etc.) become the center of discusssions.
Intentional or otherwise.

 

[pkane]

Do we prefer added distortion? It depends, some do, and there are many examples in many contests, but, for me, jury is out and will do my own blind tests with the software as suggested by the OP when I figure out what I need to use the plug-in .

In case you have not seen this yet:

INTERNET BLIND TEST: Is high Harmonic Distortion in music audible? (plus Pet Shop Boys' newest, HRA needs HDR)

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

BLIND TEST RESULTS Part I: "Is high Harmonic Distortion in music audible?" Procedures & Settings

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

BLIND TEST RESULTS Part II: "Is high Harmonic Distortion in music audible?" Respondent Results

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

 

[Barrelhouse Solly]

I've been playing guitar, acoustic, for over 60 years. I'm at the decent+ amateur level of technique. I have never heard a recording of an acoustic guitar that sounds the same as live and I've listened to a lot. If I were a trained listener I could describe the differences accurately. One thing I noticed while I was still in high school was that some recorded guitar tone sounded better than live to me. I've had the same experience with vocals. Lots of singers exploit the proximity effect of microphones and mic characteristics make the sound different as well. I'm sure that if I had the same familiarity with other instruments I'd spot the differences. I listen to a lot of chamber music and have noticed that different recordings of the same piece can sound radically different in ways other than as the result of the interpretation.

From my personal, unscientific listening experience, I'm sure that we like distortion in some form or other. YMMV

 

[Barrelhouse Solly]

Slightly OT, but because I love pre-WWII music of various kinds I've always wanted a plugin that would give my home recordings the sound of a worn 78. I've tried some and not liked them. I've also tried recording the lead in and between the notes parts of worn 78s and applied them to clean recordings without much success. Any suggestions?

 

[MattHooper]

Stereo is an illusion. Choose whatever helps you enjoy the illusion

 

[Travis]

From my personal, unscientific listening experience, I'm sure that we like distortion in some form or other. YMMV

So you must have started when you were 2?

So I always have two questions for someone who
plays an instrument. I assume the acoustic guitar is designed to project outward. Does an acoustic guitar sound the same to you when you are playing it as it does when you hear someone else playing it? Does an amplified acoustic guitar, outdoors that you see at many places, atmosphere type music, no vocals, sound like a real guitar to you? Or a real guitar amplified. Not sure I’m asking that right. If it never sounds like the un-amplified natural sound of an acoustic guitar, then a recording never will for you.

What about if you have visuals to go with it, does it make it more like the real thing, less, no different ? Like a video with high quality sound? I find, if the live recording is high quality, the visuals add to the realism vs, same recording audio only.

I think it’s a highly complex question as to why something might never quite get to what something sounds like in person. I have had numerous situations where I had a recording of solo acoustic guitar up stairs in a larger open area, and when people who have come over have remarked “who is that playing the guitar?” In disbelief when told it’s the stereo, and some of those would know what they sound like live, in a residence. I have heard others talk of similar experiences, hearing an instrument and discovered it was coming from speakers somewhere.

The common denominator of people who described being fooled has been the speakers, range of FR and how flat, and the room, physical layout.

For natural, life like guitar, but with vocals, one of my go tos is Muddy Waters Folk Singer. I sure there are many others.

 

[MattHooper]

Buy a perfectly transparent system, add some plugin, as you do, and you'll be able to mimic (and best) any of those fancy "high end" systems for a fraction of their price.
And in a much more flexible/sensible way.

In other words: take all the fun out of it

That's sort of like saying "Why not just digitize all your vinyl? Then you can listen to it streaming digital and take all the hassle out of using that physical media?"

There's other considerations that go in to enjoying taking one approach over the other, including the joy of the actual Physical Thing and conceptual pleasures associated with it. That goes for owning and using a Tube amp as it does for owning and using records.

The "solution" you suggest is, ironically, the least likely option anyone will use. It won't appeal generally to the type of people who buy tube amps, and it won't appeal to the type of people who first off seek a "transparent" system in the first place and who'd think of such solutions. Your solution is "logical" to the people who would logically reject coloration in the first place. Which is probably why you haven't (I presume) used such a solution in your system.

 

[MattHooper]

As this thread has indicated, there are all sorts of questions wrapped up in this subject: is there distortion in the first place? Is it enough to be audible? Is it actually preferred? If so or if not, why? And if some distortion sounds good, does it sound good on everything or just some things?

Since tube amplification has naturally come up as an example of possible distortion generation...

What I heard during my blind testing of my CJ tube preamp vs my Benchmark SS preamp was consistent with my sighted impressions:

Blind Test Results: Benchmark LA4 vs Conrad Johnson Tube Preamp

Hey folks, I thought I'd post about a little blind test I did between my two current preamplifiers: Benchmark LA4 vs. Conrad Johnson Premier 16LS2 tube preamplifier. People are familiar with the Benchmark LA4 I'm sure: https://benchmarkmedia.com/products/benchmark-la4-line-amplifier A...

www.audiosciencereview.com

ASR members can decide for themselves how much stock to put in the above. And, naturally all the following is FWIW....

But IF (for sake of argument) I've heard some audible distinguishing characteristics between tube and SS amplification, my observations are, in my system:

1. I find it a pleasurable addition across ALL content - any instrument/voice be it acoustic or electronic. Any genre. And agreeable across all levels of recording quality, from crap to "audiophile quality" recordings.

I still have my CJ tube preamp running through my Benchmark LA4 so I can flip between them with the press of a button. Occaisionally level matched, but aside from the above blind test, I'm referring to the general impressions (that I also heard blinded):

2. Example: Last night I was listening to an amazing recording: A live recording of Antonio Carlos Jobim/Astrud Gilberto singing Girl From Ipanema (Verve Jazz Masters Astrud Gilberto CD). This is a quirky recording but it is also astonishing. Jobim begins lightly singing and it's like he's right there whispering out of your Left speaker. The drums, when they come in, are all piled up tight on top of each other stuck to the Left side. BUT...when Astrud begins singing it's a shock.
She just appears, beamed down, in to your room. She's recorded so dry it's like she's in her own isolation booth, so it's odd sounding, but for a vivid sonic image of a singer it's hard to beat. Also, Stan Getz's sax solo sounds beautiful, both big, rich, soft and deep in the soundstage behind Astrud. Try it out if you haven't heard this one!

Anyway...run through the effectively zero distortion Benchmark preamp the sound is spectacularly clean and clear. "Couldn't get better" in some ways. But...click...I switch over to the signal going through the CJ (which happened to be at a slightly lower volume level) and it gets "better" in some ways. The main impression is an increased sense of solidity and corporeality to all the sonic images, and a slight increase in presence, of texture to the sound. With the Benchmark the vocal is super clear and clean, but compared to the tube preamp, it sounds more "see through" like I can wave my hand through the apparition. With the tube preamp it sounds more solid.

When the Sax solo begins, paying attention to the drum work in the Right speaker, mostly cymbals and rim shots, switching to the Benchmark wipes away a slight scrim of texture/noise, so that the exact harmonic/timbral nuances of the different cymbals shimmering seems better revealed, same with the rim shots. I like that.
However, switching to the tube preamp: those cymbals and rim shots become more solid, thicker, more like a solid instrument "right there" being struck. It's subtle...but significant if you care about such things, which I do. Does the tube amp cover up and homogenize the instrumental differences and timbre? No, not by a long shot. If there's distortion it is very subtle relative to the gross sonic characteristics in the recording that distinguishes one instrument from another.
Yes instruments become a *bit* more homogenized, but are far from totally homogenized. The effect is mostly "things sound a bit more real and there."

This is essentially what I have found in comparing both my tube amps and tube preamps to solid state over the years. I hear things I like better in the less distorted SS presentation, things I like better in the tube presentation, and this balance is virtually always the same no matter what recording I'm listening to. And I usually prefer the tube presentation. So it's not based on "well I'm listening to X genre" or "this is an excellent recording I don't want to muck it up with tube distortion." The same benefits and deficits are there in any recording, to my ears. So it's just "what flavor...or not...do I want today?"

One more thing: The choice of what is more logical or rational to use in our system will have to include an individual's psychology too, our individual goals/proclivities etc. So for instance, right now I actually have something like what many have advised - at least in terms of preamplification, I can switch the tube effect in and out at will. So...perfect solution? Uhm...it turns out to be a bit of "be careful what you wish for" in my case.

I'm thinking of not running the CJ through the Benchmark anymore, and simply directly connecting one of them at a time to my amps. Why? Because when I have the option at my fingertips to switch between presentations I can start to get distracted. "I wonder what this sounds like with the Benchmark...or the CJ?" Flip, flip....

I went 20 years with none of this inclination to keep altering the sound this way. It's why I got rid of my digital EQ that I never used. It's similar to why I started listening to records again after I set up streaming: too much easy choice at my finger tips became something of a distraction for me.

So hooking the pre-amps directly in to the amps will put a bit of a brake on easy switching, so I'll just live with one or the other for a while.

 

[Rja4000]

In other words: take all the fun out of it

Indeed... (for some)

The "solution" you suggest is, ironically, the least likely option anyone will use. It won't appeal generally to the type of people who buy tube amps, and it won't appeal to the type of people who first off seek a "transparent" system in the first place and who'd think of such solutions.

If you except me, maybe.

Your solution is "logical" to the people who would logically reject coloration in the first place. Which is probably why you haven't (I presume) used such a solution in your system.

I actually did it.
Not in HiFi (yet), although I happened to try and measure the proposed "effect" in the Topping D90LE.

I also happen to own 8 channels of mic preamp that allow convolution simulation of famed preamps, and also to add distortion to taste.
I performed some basic measurements on them as well.

I actually believe this is the way for the future of HiFi. (And the end of the last "High End" Hi-Fi dinosaurs.)

Bob Carver has done a similar thing in the past.

Providing some presets would help anyone to benefit from those effects.
And as long as they are just that: effects you add to taste, at will, it's just for the pleasure.

One may understand at the same time that science and control are paramount, and that music enjoyment is allowing fantasy and subjective choices...
Optional choices.
At a sensible cost, of course.
(And if you want to also lit a (fake) "Tube" light for the gallery, why not ?)

EDIT: All this, I realize, is based on just a theory so far.
The attempts I spoke about above are not really convincing.
We'd need first to assess seriously, scientifically, which (combinations of) effects are really audible... and, somehow, (sometimes) desirable.
Then quantify them, and emulate them in an easy, cheap, usable way.
I'm nowhere near anything like that.
Is anybody more advanced ?
That's the topic of this thread, I suppose.

 

[Sal1950]

Be careful talking about DSP around @Sal1950.
I think he means it about MQA.

You betcha.

 

[MattHooper]

I

I actually did it.
Not in HiFi (yet), although I happened to try and measure the proposed "effect" in the Topping D90LE.

There's the rub. Not in hi-fi, yet.

People have been suggesting this "just add a plug-in for distortion" approach for years, but for most of that time there hasn't been any such plug ins for consumer gear, or certainly not easily integrated in to a consumer system. That still seems to be the case as far as I know. A tube amp for most is just plug-and-play.

I work daily with a DAW (Pro Tools) but I am not looking to try to integrate any of the plug ins with my two channel systems. Some other people may want to get their geek-on and do that type of thing, which is fine. But I suspect it will remain the very rare audiophile who takes that approach to coloration.

 

[Rja4000]

There's the rub. Not in hi-fi, yet.

People have been suggesting this "just add a plug-in for distortion" approach for years, but for most of that time there hasn't been any such plug ins for consumer gear, or certainly not easily integrated in to a consumer system. That still seems to be the case as far as I know. A tube amp for most is just plug-and-play.

I work daily with a DAW (Pro Tools) but I am not looking to try to integrate any of the plug ins with my two channel systems. Some other people may want to get their geek-on and do that type of thing, which is fine. But I suspect it will remain the very rare audiophile who takes that approach to coloration.

You have a point on this.

There isn't an easy tool that offers a real experience to compete with real hardware "effect generators", like tube amps or transformer-based outputs.
There are some VST for studio use, but they are rather meant for one channel/instrument than for a finalized mix.

Also, Roon, as an example, doesn't allow VST plugins.
(I'm sure though they'll have to find a fix to that, since that will kill them, sooner or later)
And no other basic HiFi system I know of allow them either.

But there is a market for it.
(Of course, if a convincing set of "effects" CAN be produced.)

This would be an obvious complement of those low cost transparent systems we crave about here.
And the logical next step towards audio nirvana.
The final end game solution.
IF it works... ;-)
(And, well, there is still enough to invent in the speakers and multi channels area to keep the industry busy for some decades after that, IMO)

 

[Sal1950]

That's sort of like saying "Why not just digitize all your vinyl? Then you can listen to it streaming digital and take all the hassle out of using that physical media?"

Smartest thing I've heard posted, that's what I did with all my LP's almost 20 years ago.

 

[Rja4000]

@MattHooper
Would you know where to find proper measurements of your Conrad Johnson Premier 16LS2, by any chance ?
That would be very interesting.

 

[Sokel]

@MattHooper
Would you know where to find proper measurements of your Conrad Johnson Premier 16LS2, by any chance ?
That would be very interesting.

Conrad-Johnson Premier 16LS preamplifier Measurements

Sidebar 3: Measurements Measurement-wise, Conrad-Johnson's Premier 16LS was very similar to C-J's Premier 17LS, which Brian Damkroger reviewed for Stereophile in May, in that many of its "static" parameters varied with the setting of the volume control. Fortunately, because of the very high...

www.stereophile.com

 

[MattHooper]

Smartest thing I've heard posted, that's what I did with all my LP's almost 20 years ago.

Once you start digitizing your vinyl you've given up.

I'm a survivor.

 

[levimax]

Conrad-Johnson Premier 16LS preamplifier Measurements

Sidebar 3: Measurements Measurement-wise, Conrad-Johnson's Premier 16LS was very similar to C-J's Premier 17LS, which Brian Damkroger reviewed for Stereophile in May, in that many of its "static" parameters varied with the setting of the volume control. Fortunately, because of the very high...

www.stereophile.com

Hi @MattHooper, interesting measurments, what position is your volume control set at for critical listening? Do you know the input impeadance of your power amps?