Is the appeal to euphonic distortion learned?


Hi everyone,

I have been thinking a little bit about the idea of euphonic distortion. The idea that we can make an amplifier or preamplifier sound better by not being so absolutely true to the input. The common story is that by adding 2nd order harmonics the music sounds more pleasant to more people. Certainly Pass has written a great deal, and with more nuance and detail about this and makes no bones about his desire to make a good sounding, rather than well measuring product.

Lets keep this simple description of euphonic distortion for the sake of argument, or we’ll devolve into a definition game.

I’m wondering whether it is possible that this is in large part learned? For instance, if I grew up with non-euphonic amps and then was exposed to an amp with high amounts of 2nd order distortion would I like it? Is the appeal here one which you have to have learned to like? Like black coffee through a French press?

And this discussion is of course in line with my thoughts about the ear/brain learning process. That there are no absolute’s in music reproduction because we keep re-training our ears. We keep adjusting what we listen to and ultimately at some point have to decide whether the discrimination between gear makes us happier or not. (Go ahead writers, steal this topic and don't mention me again, I know who you are).
erik_squires
The late psychiatrist and writer Oliver Sacks has a book, Musicophilia, that I think addresses some universal human preferences for harmony and against dissonance. It’s been a while since I read it, but as I recall the preference is found in some animals as well. You might look for it. Even if I remember it completely wrong, it’s a good book, like all of his writings.
Learned?



Great story , great read thanks!

Most things we think are the better are social conformity conditioning, but this remark does not negate the fact that a very good tube amplifier has his own qualty, but only relativized it...

My best wishes to you....
I find the concept thought provoking. Not the usual measures vs sounds. Not the usual ss vs tubes. Makes me think about how much as cigarette companies altered nicotine levels, food manufacturers alter: fat/ salt/sweet to find “ perfect food addiction “ levels- too much of any one makes enjoyment lower.
I ‘ve had my kids listen w me for years. We don’t always have the Same perception or words to describe-
I remember when my son was about 5 changing crossover settings on a pair of speakers he said something like :”this one’s louder, but I liked the other one better”.
I asked why, what did he hear, he said:” It was more together”.
I told him I thought so too.
That said, I remember my father building Eico tube gear at the kitchen table.
I didn’t care for the hum as a kid.
But after listening to ss gear for years, got a wild hare, took his old Eico gear into local shop, had them clean it up & get it working right, it was beautiful- eye-opening!- Not sure how but they even decreased the 60 cycle hum-
maybe he didn’t build it that well.
Learned?
You tell me.
Funny aside- years ago, I was in high school- Dad sent me to local shop to get replacement tube- cuz one tested bad on the machine at the 7-11. When I drove to the shop, sales guy said best to replace all power tubes at once- EL-34s.
no cell phones then, asked to use store phone to call my Dad.
He said:”There’s only one Goddamn tube that’s bad- just get one!”
So I paid ~ $8 for the single (Mullard) tube & went home.
Ft Worth, Tx 1970 something.
i do prefer tube gear now.
Learned?
I hope I am remembering the proper name, but as I recall, Jame Parker of Audio Research has been said to intentionally add second harmonics his amps.  Also, the original Sequerra Model 1 tuner was said to have such, which made it sound very sweet and musical.  I think this is why so many people prefer tubes. 
i do not see it being so complicated.  you either love the sound of the music or you do not.  
when i first heard a sweet sounding Raven Audio tube amp Ioved the sound so much i bought it on the spot.  no learning involved.  
imho learning would mean preferring sub par sound quality because you are accustomed to it.  an acquired taste for bad sound...
I will add that my experiences suggest that what one hears from the typical audience perspective  can be quite different than what one hears from the performance band stand.
That's certainly true!
@atmasphere , For the purposes of this discussion, and for the very reasons you suggested; please feel free to ignore the last paragraph of my previous post on this thread that began with: “As a personal aside....” I will add that my experiences suggest that what one hears from the typical audience perspective  can be quite different than what one hears from the performance band stand. 
The answer is to have a great SS Amp and a great Tube Amp...no problem!


That's a recipe I've heard many times and it sure sounds purty, especially with very hard to drive ESLs.


@atmasphere , For the purposes of this discussion, and for the very reasons you suggested; please feel free to ignore the last paragraph of my previous post on this thread that began with: “As a personal aside....” I will add that my experiences suggest that what one hears from the typical audience perspective  can be quite different than what one hears from the performance band stand. 
Someday we will begin to understand the relationship between sound waves and how the brain reacts to them. For now it seems we know
about 1/2 of 1% of what can be known. 

How do people who could not memorize 3 lines know when
a musician plays the wrong note after only hearing it once before?
Or even if they never heard it before?

Musical sounds occupy a special place in the brain that allows total recall of everything ever heard. This is fascinating to me.

The real question is whether or not someday we will have learned
how to build a sound reproduction system in a way that is
indiscernible from live music. 

We have a long way to go before that happens so do enjoy the ride!


Note that recording studios often are the worst places to listen to instruments (unless it's a large great sounding room with good acoustics...Abby Road has one) as they're designed for recording into microphones. Many charming little pro studios manage to do recording very well, but they're not concert halls or often even good sounding rooms. Kind of not the point. These days you can carefully record things clearly and cleanly in your closet.
 As a personal aside, as a young man, for several years I attended musical events almost every night of the week, most of which were unamplified. To this day I find that while tube amps can sound pretty, they don’t sound like the live performances I attended...unless a musician used a tube instrument amp during the performance.
I'm guessing that isn't learned other than your ear is a bit more trained and you've not heard the right tube amp... yet... ?


I play bass and keyboards and from junior high through college and afterwards I played the string bass in a variety of orchestras around town, as well as jazz and folk ensembles. You'd think I would have learned the same thing as you but I didn't, I found that solid state amps of the time were simply incapable of a natural presentation. So it was the opposite 'learning' from yourself (and not discounting your experience in any way).


Since both experiences are subjective and anecdotal, is that the sort of thing we can ignore for this conversation or is that exactly what this conversation is about??


 
A few years ago I read an article about how young people seemed to prefer listening to MP3 through cheap ear pods than higher resolution media through well measuring high end audio systems.
 It appears to me that when people attend concerts; people often prefer to hear the old classics rather than new material.
 All this suggests to me that people have a neurological response to the familiar, and in answer to the OP question; imho yes, the appeal of euphoric distortion is learned,
 As a personal aside, as a young man, for several years I attended musical events almost every night of the week, most of which were unamplified. To this day I find that while tube amps can sound pretty, they don’t sound like the live performances I attended...unless a musician used a tube instrument amp during the performance.
By adding a simple vacuum tube you can flavor even harmonic 
distortions per brand of tubes ,in a good way .
even SS gear can voice their gear very close to Tubes in some respects Jfets, Mosfets, matched Bipolar transistors ,all have harmonics similar to pentodes in many ways with even more precise lead edge detail.many engineers build the harmonics
into the design per their interpretation of what is harmonically 
pleasing.
Overthinking...either it grabs you or it doesn’t
Hopefully these discussions can educate. Maybe someone may realize they like something different than their preconceived notions.  For example, after comparing many FM tuners I now prefer a 1950's Fisher tube tuner over digital HD radio. After many comparisons, I prefer SS pre-amps with tube amplification. Discovering, "what we like" is part of what makes this enjoyable. We all over time learn what characteristics of sound we prefer.  
@atmasphere I think a lot of people will be looking forward to that!

I will hang on to my current amps at least a bit longer then....

If the Class D amps don’t turn out to be greener than the average tube amp, that would be something!
@mapman FWIW we are beta testing our class D amps right now. If we don't run into any emissions issues we expect they will begin production later this spring.
There is recorded music that is pleasing to the ear and then there is live music. I only want the harmonics that actually occurred when the people played. Good or bad. No artificial sweeteners please! Probably the main reason I have dabbled with tube gear but never taken a big plunge.

Looking forward to actually seeing, reading about  and maybe hearing the Atmasphere Class D amps if/when they actually come out though.  That will be interesting!
if the increased ratio of second and/or third order harmonics in tube equipment masks the higher order harmonics, are you also saying that the frequency response of tube amps in the highest audible frequencies is NOT lower than that of SS amps, but we just don’t "hear" those higher frequencies because they are masked by the 2d/3d orders?
Yes.
Because that means nothing at all comparing tubes/versus S.S. in general...
My post was not meant to address tubes/transistors, it was meant to address how distortion interacts with our ears. What I did not mention in that post is that if you can apply enough feedback to a solid state amp it will sound very natural and the typical brightness and harshness on top will be gone. But that is a tricky thing to do because of something called ’phase margin’ in audio circuits. Essentially there are frequency poles which cause phase shift. At some high frequency, these poles cause enough phase shift that feedback becomes positive rather than negative and the amp will oscillate. This is why for many decades amps have not had enough feedback; with insufficient feedback the circuit will be brighter and harsher than real life. Hence the ’solid state’ sound of the last 50 years.
By the way the human hearing faculties are way less more deceptive that "skeptic sunday scientist" says they are... Reason is simple, evolution.... recognizing timbre voice speech and the source of sounds is vital tool for survival.... The first sense to be born is hearing, the baby listen his mother voice, and in coma and death you can speak with people, it is the last sense organ to go....
If you want to talk about evolution, the ear is the most sensitive at birdsong frequencies as the birds are the first warning that a predator is in the area. This is the Fletcher-Munson curve.
The sound was pleasant but not $100k worth to me. Euphonic as all hell. Detail I know is there was gone, replaced with a warm blanket of sound. So is the loss of detail and an abundance of warmth a result of frequency response or an excess of 2nd harmonic distortion?
This sure sounds to me like an amplifier with too little feedback. Distortion of all types will reduce detail. You know you are making progress when you experience smoothness and more detail at the same time. The smoothness is a lack of higher ordered harmonic distortion and IMD; the detail comes from that lack of distortion.


Amps that exhibit a 2nd order as their primary distortion component have what is mathematically a ’quadratic non-linearity’. A good example of this is an SET where the 2nd harmonic dominates. But the higher orders do not fall off all that quickly; it is only the 2nd (and the 3rd which appears at a lower level) that mask the presence of these higher orders. Because the distortion is so profound, quite simply there is detail lost while sounding otherwise quite smooth.
For instance, I love the Conrad Johnson Premiere 12. They are the ne plus ultra of amplifiers in my mind. Neutral? Hardly! But I can’t really explain why. Those are just very colorful seductive amps.

I was wondering about distortion specifically.
When you combine single-ended and push-pull you have two non-linearities- quadratic and cubic. The Cubic expresses the 3rd as its dominant harmonic component. Due to algebraic summing, this type of circuit typically also exhibits a bit more prominent 5th harmonic. But it will have a lot of the 2nd as well. Distortion does not fall off all that quickly as the order of the harmonic is increased. This is the traditional ’tube sound’ coming out of the golden age of hifi with such amps as the Citation 2 or Dynaco ST-70. Feedback is used to control distortion and to a limited extent reduce the output impedance, but 12-15dB is typical as much more than that risks oscillation. So you get a rich sound (not as rich as SETs) and that 5th sort of acts like a touch of detail.


IMO/IME if you want to use a tube amplifier, getting away from that 2nd harmonic will really allow the amp to be far more neutral and transparent. The only way to do this I know of is to run the amp fully differential from input to output, so that it mostly expresses a 3rd harmonic as the dominant. **This is a good practice for solid state too** and for exactly the same reason! The 3rd is treated the same by the ear as the 2nd but in such circuits often occurs about 1/10th the amplitude as the 2nd is in SETs (this is assuming open loop- no feedback). The tricky bit is that even orders are cancelled not just in the output section but in each stage so distortion isn’t compounded from stage to stage through the amp. For this reason amps with a cubic non-linearity have the succeeding harmonic orders falling off at a faster rate (hence ’cubic’). The reduced higher orders allows the circuit to be smoother and with more detail!
I have one special tube amp and class Ds, can’t seem to decide between them.
Class D amps are a special case of solid state. They can be run with zero feedback (the big trick with zero feedback examples is that RFI and EMI emissions are hard to control), a little or really quite a lot. The high feedback amps have feedback so high that they actually are designed to exceed their own phase margins and go into oscillation! This type of class D amp is known as ’self oscillating’; the oscillation is used as the switching frequency. They have the advantage of being able to use prodigious amounts of feedback in excess of 35dB because they are already oscillating. This allows them to clean up the distortion caused by the feedback itself (which tends to be higher ordered harmonics and is why amps with insufficient feedback have a brightness to them that isn’t natural). So such amps can sound very smooth, much like a really good tube amp.
dave_b
... So much nonsense spewed out over such a simple equation ... Listen and decide for yourself and stop pretending to be able to quantify the experience!
It really doesn’t matter what other people do. But what’s odd is that the measurementalists here seem to insist that we are somehow obligated to them to provide things such as results of our own blind tests. Time and again, we read posts such as "the onus is on you to ..." when no such obligation exists. Those who resist such demands have - over just the last few days - been told their opinions are "worse than useless" and that they are stupid, or deluded, or have ulterior motives.

For those who seek absolute, documented, verifiable scientific data, I can only note: This a hobbyist’s group, not a scientific forum. Please take those demands elsewhere.

I’ve also noticed that the measurementalists don’t seem to offer the results of their own blind testing. Why is that?
Ejaculations...good call 📞. So much nonsense spewed out over such a simple equation.  If you appreciate live sound, acoustic instruments or the human voice, everyone can tell when something sounds authentic.  Listen and decide for yourself and stop pretending to be able to quantify the experience!
@erik_squires  You got me thinking and it might be learned but not from equipment. My hypothesis is that certain harmonics are more pleasing to the ear but they may be conditioned by the musical system we are accustomed to. My reading of Nelson Pass's thinking is that he feels even order harmonics (the octave) have this inherent quality. I like that but the problem is that the third order harmonic is a perfect fifth in music and that certainly is pleasing to western ears. (Apologies to Mr. Pass if I interpret him incorrectly). Also chords are basically made up of thirds. So lets I change that to lower order harmonics are pleasing to western ears.  I think that works and invite correction from those more versed in this than I.
So if lower order harmonics dominate from acoustic instruments using western tunings then it would follow that equipment that reproduces music would also please if the main distortion it introduces is consists of lower order harmonics.

Lets see if this withstands the scrutiny of the learned members of our forum:-)
Bruce
Is audio equipment voiced for the public or what the designer thinks sounds the best?  None of it is perfect.  We have to get used to what we hear.  Initial listening can be "oh my"  to wincing.  Later on, it can still be bad or good.
The question of the OP was both scientific and biographical. The best scientific answer to “is euphonic sound enjoyed because it’s learned?” — IMO came from atmasphere. Other more autobiographical answers to the question were really interesting...for myself, I cannot tell if my taste in tubes is learned or not, but I certainly discovered it much later in life. Just wasn’t in most of the audio shops where I was looking, before, in the 80s and 90s. 
A few of the comments are are downright anti-curiosity. I’m amazed, still, that people choose to put in print such troglodytic ejaculations. Go yell at the weather, FFS.
As far as the overextended object lessons in “embedding”, well, all I can say is that I’ve been doing nothing but fine tuning my room for the past 5 months and every time I get it to a good place, I switch from SS to tubes and it’s like a glorious rainbow appears over an already beautiful vista. So, no, the gear is not way down on the list for me. It’s very integral to what I’m seeking. 
Far to often these conversations revolve around pre conceived notions or generalities about how certain audio equipment sounds.  Most of these comments are from people who have not even experienced what they are portending to understand.  There is bad SS and bad Tube gear...excellent SS and Glorious Tube stuff.  One fundamental that is noticed however, is that with great tube gear, instruments are portrayed with more texture, harmonic complexity and density.  SS tends to constrict the acoustic envelope of instruments, almost like a digital device samples the musical waveform, and then interpolates it back at the output stage.  Tubes allow the whole wave of sound through, which when done right (Decware) simply sounds more complex and completely satisfying!
Most grew up with car radios and tv "sound". Once exposed to better equipment, be it Bose or Pass or tubes, the difference was so striking it did not matter if euphonic or integral. Sort of like fishing with live bait or artificial. You should learn both but choose dependent on a desired result. However some descend into madness.
From exposure to real instruments being played in recording studios, I'm not a fan of euphonic sounding kit. In my experience, how things sound in the studio is both "brighter", "faster" and "harder" than quite a lot of the more euphonic-sounding kit reproduces.

In general, being in an acoustically-managed space with live instruments is not that relaxing. It's very intense. Some of that intensity is lost by the time we experience it at home. Some equipment removes it even more, but in so doing, sounds rich, relaxing and toe-tapping. It sounds lovely, but it isn't high fidelity to the original recording.
I grew up with tube radios and a Voice of Music tube large portable record player.  1953 until 1968.  Have owned at at least 20 different solid state amps since. Class A/B never seems to satisfy my listening.  I have one special tube amp and class Ds, can't seem to decide between them.
I agree with @dave_b the audio performance on an amplifier, pre-amplifier or any audio reproduction gear should only be compared against how the musical instruments (especially the classical ones) and the human voice sounds at real concerts (preferably in a small venue/hall and without the use of any amplification that inherently induces harmonic distortions) sounds like.
During my youth I had the privilege to go to many live concerts in theater halls, jazz clubs, classical music concerts, etc) and I know how the instruments really sound. Once your ear is accustomed to those live sounds it becomes easier to distinguish audi that it’s reproduces through electronics and speakers and tell which ones are closer to the real sound than others.It always puzzles me that speakers/amplifiers/pre-amplifiers that add coloration and/or a certain degree of harmonic distortions, sound better to some people. This could very well be something they have "learned" by only listening to music from recordings or from live performances in large venues where the sound comes from large speaker systems and amplifiers anyway.
When you hear live music played on good piano, violin, cello, flute, oboe, timpani, cymbals etc. from close by and without any amplification, it will completely change your perspective on how music can and should sound.
@atmasphere if the increased ratio of second and/or third order harmonics in tube equipment masks the higher order harmonics, are you also saying that the frequency response of tube amps in the highest audible frequencies is NOT lower than that of SS amps, but we just don't "hear" those higher frequencies because they are masked by the 2d/3d orders?
We all had parents of a variety of cooking skills and tastes, but that's what we learn as homey, and no restaurant can match it.

If I went to a restaurant and it tasted like my mom's cooking, I'd run out as fast as I could.
This is why I tried to define "euphonic" very narrowly.  It is super hard to talk about why we like colorful gear.

For instance, I love the Conrad Johnson Premiere 12.  They are the ne plus ultra of amplifiers in my mind.  Neutral?  Hardly! But I can't really explain why.  Those are just very colorful seductive amps.

I was wondering about distortion specifically.
I was absolutely transfixed by the sound coming out of affordable KLH acoustic suspension speakers before I knew they were being driven  by McIntosh tubes, and I didn't  know what McIntosh was.  I always wondered whether it was the tubes/2nd order distortion or the sheer power and control the McIntosh was able to deliver. It was my first encounter with tubes. Never bought McIntosh but now own VAC and love to listen through it.  Seems more fleshy.
I would think undoubtedly, arafiq. I mentioned this briefly on another thread. Not too long ago I was listening to a record, and I actually cupped my hands behind my ears. The result was staggering, the soundstage was immediately enormous compared to what I was used to hearing, everything was just "more". Made me a bit sad, lol. If you’re young, take care of your hearing.
I often wonder if there's a correlation between appreciating euphonic distortion and gradual hearing loss (otherwise known as getting old). 
People like different sounds and types of equipment but i have noticed when shown a true superior product the likelihood that almost all of the people will like the product is very high like 9 out of 10 even in large groups. When you play music on that special piece or system it will draw a group of people to hear it because they have never heard that type of sound before.
Powered artificial (pre & amps) interaction is influential no matter which type distortion, how much distortion, how little distortion. The very acoustic backbone of sound is in the overtones. This is the math and science turned into art. Do you hear it ?
If you've ever looked through yellow tinted glasses, it's amazing how bright and pretty everything looks. And how artificial. I'm not interested in my music getting a boob job. JMO.
I grew up listening to cheap solid state.So the nurturing pushed me away from that and into the sound of tubed equipment. It sounds so much closer to live music to me
I heard a TW Raven with big tube monobloc amps and Agora granite speakers at AXPONA. Two albums I know well. The sound was pleasant but not $100k worth to me.  Euphonic as all hell. Detail I know is there was gone, replaced with a warm blanket of sound. So is the loss of detail and an abundance of warmth a result of frequency response or an excess of 2nd harmonic distortion?
To the original post.

My mood and time of day can determine how and what flavor i want to listen too. Real live sound for long periods of time can be overwhelming, sometimes a little sugar coating is needed i relate it to having a drink after a long hard day.
The horse is dead. Do we have to keep beating it?

Use your ears. It's what they are for.
There is a definite sound and a feel to live music that anyone can easily identify.  When you can get close to that reality, you are golden!
A lot of high end approved gear sounds like your listening to the players in an anechoic chamber.


I had this happen to me at Goodwin's High End.  They were nice enough to let me listen to Avalon Acoustics all ceramic speakers with Spectral gear.

There is never any accounting for personal preferences.  Anything is possible.
Skinny Puppy - Amnesia

Great song. Plenty of distorted bass. If you like this kind of distortion, get a nice tube amp.
A lot of high end approved gear sounds like your listening to the players in an anechoic chamber.
Many people really think that the sound coming from a 100,000 speakers is ALWAYS better than a 1000 dollars one....They trust the price not the room and not their ears, and there is NO musicians in this group and thread....Musicians dont buy audio product because they are the more high cost....


Give any speakers to a skilled acoustician, it will make one sound bad the other heavenly, with no regard to their price.....

But understand me right, a 100,000 bucks pair of speakers is probably better designed than a 1000 bucks one.... But the key factor that will distinguish them could be and is often the room controls....

By the way the human hearing faculties are way less more deceptive that "skeptic sunday scientist" says they are... Reason is simple, evolution.... recognizing timbre voice speech and the source of sounds is vital tool for survival.... The first sense to be born is hearing, the baby listen his mother voice, and in coma and death you can speak with people, it is the last sense organ to go.... The ears and hearing faculty in men can learn a lot and increase in experience, in musicians for example, way more than the eyes could be trained themselves... The reason is that in sounds experience, content and meaning are very important factors which ask constant  translation and interpretation....

Then yes the ears can be deceived, but not so easily than said by the obsessive blind test group of skeptic scout pretending  it ....