What is “warmth” and how do you get it?

its very simple. try attenuating the frequencies between 3 and 5 k by say 3db and increasing the spl by 3db between say 90 and 200 (i may be a little off here) and , voila! warmth.

In 1970, a girl who I shared a house with, had a Fisher tube receiver and a pair of KLH bookshelf speakers that were given to her by a friend. Thats the first time I experienced "warmth" which totally had me captivated. Warmth is a full, rounded, refined relaxed sound that has a silky thickness and velvet texture to the music. A more of a full body to the sound where the upper frequencies seem to bend down more and blend and integrate into the mid-bands. From that era, several factor's come into play. Tubes at the time that were made by Sylvania, Zenith, RCA, and GE, were better built then the best tubes of today. Back then they had double glass envelopes, heavier filaments, and the technical artists who made those tubes are non-existent today. They were like composer's. In fact, the hardware machines are still in existence collecting dust at those companie's, but their is no one around today that has the technical ability to revive the technique and skill to make those tubes. A lost Art. The tubes from that time would last for ten years or more, as compared to tubes today that are good for 4K to 6K hours. Another fact is at the time, speakers had a lower sensitivity of 83 to 86 db's. Speaker's today with sensitivity between 90 and 96 db's, have a more aggressive open top end. Speakers with much lower sensitivity have a more relaxed character. Back then most amplification in homes was between 25 to 40 watts. Also, tweeters back then were more simple and basic, and it wasn't until the late seventie's when Phase Technology in Florida invented and built the worlds first ferrous oxide fluid filled tweeter which improved the dynamic range. For the most part, it was the tube designs from fifty years ago that gave us that warm, rich, full velvety sound. If those type of tubes
came back on the market, we would return to the full analog glory that has been lost.

Some times, it could be as easy as swapping the source I/c. Not to alter freq response but take that electronic tinze/noise surrounding the notes. I have three sets of cables at each source, same corresponding brand for each level of sound i desire- neutral, slightly warm and warmer. You will be surprised how 'listenable' most music would become... true changing cables every once in a while is a chore and one set of cables is always your primary choice. It is no different than some folks trying different tonearms, cart, diif DAC sampling, diff sources...

One characteristic that warmer sound gets you is the image size ( overall- fundamental and harmonics and air) of instruments become life size which I personally consider primary requisite.

“and how do you get it”… I just went to “warm” by changing the footers under my CDP from Stillpoints to HRS Nimbus Couplers. I really liked what the Stillpoints did, but at times my system sounded a little “thin”. Without losing any of the good that the Stillpoints brought, the HRS Nimbus Couplers added what can best described as “weight”.

Looking back on this thread, I have another thought...

There has been a lot of discussion about how increasing warmth in a system might involve ADDING something to the signal, like low order harmonics. It occurs to me that increasing warmth might also involve SUBTRACTING something from the signal.

Maybe the most obvious example of how subtracting something from the signal might increase warmth is subtracting treble, which amounts to the same thing as adding midrange/bass. A less obvious example is contained in Al's second post on 2/6, namely subtracting destructive acoustical effects like comb filtering. One final example that I have personally experienced is subtracting (or at least reducing) jitter in digital playback, which to my ears increases the perception of "warmth."

Bryon

I'm not sure that the variable/constant distinction is particularly meaningful, even within the limited context of harmonic distortion. The harmonic components resulting from distortion in the electronics will continuously vary as a function of the varying spectral components of the music, and to some extent with the overall signal level.

I agree with this, Al, insofar as I recognize that the harmonic content introduced by equipment varies as a function of the spectral content and level of the input signal. So perhaps "variable vs. constant" is not quite the right distinction.

The distinction I was trying to capture is between the harmonic content of the live event vs. the harmonic content of the reproduced event. To the extent that the recording process diminishes the harmonic content of the recording, the additive approach to playback may do something to replace what is missing. But it cannot, so far as I am aware, replace the EXACT missing harmonic content, since the harmonics introduced by equipment are, in essence, artifacts.

The fact that equipment-induced harmonic artifacts vary as a function of the spectral content and level of the input signal does make them "variable," perhaps even as variable as the harmonics of the live event. Nevertheless, equipment-induced harmonic artifacts are not SIMULACRA of the harmonics of the live event. That is the flaw in the additive approach to playback that I was trying to point out.

Bryon

Hi Bryon,

... The issue of whether instrument timbre is reducible to harmonic content. I am completely out of my depth here, so will remain agnostic.

Let me make sure it's clear that implicit in my previous post (the one with the lengthy quotes from the "What Is A Sound Spectrum?" writeup) is that I now recognize that timbre is only partially reducible to harmonic content, and other factors also affect timbre significantly. An example of those other factors is the low level broadband component of the flute spectrum that the article discussed. I still suspect, though, that for most instruments harmonic content is typically the most significant determinant of timbre.

IF instrument timbre is EVEN PARTIALLY reducible to harmonic content, then it reveals a flaw in the “additive approach” to playback.... What is ADDED during playback will not be identical to what was SUBTRACTED during the recording process. The reason is because, while the harmonic contents of live events are almost infinitely VARIABLE, the harmonic “additions” of playback equipment are largely CONSTANT, being persistent artifacts of a circuit's more or less fixed parameters.

I'm not sure that the variable/constant distinction is particularly meaningful, even within the limited context of harmonic distortion. The harmonic components resulting from distortion in the electronics will continuously vary as a function of the varying spectral components of the music, and to some extent with the overall signal level. Harmonic distortion introduced by the speakers will vary with signal level as well as with frequency, and will often overshadow the distortion components introduced by the electronics. Throw in intermodulation distortion, transient intermodulation distortion, the complexity of the music, the complexity of the sounds of the instruments themselves, hall and room effects, the vagaries of the recording process, etc., etc., and the “approximation” you spoke of would seem to be all that can be hoped for, regardless of the approach that is chosen.

The upshot of all this is that, in light of my desire for additional warmth, maybe I chose the wrong amp.

On the other hand, as was said earlier, with your speakers an amp having a high output impedance (such as the Prima Luna and probably most other tube amps) will de-emphasize lower frequencies relative to upper mid and high frequencies. Obviously, that would be in the wrong direction with respect to adding warmth.

So I'm not sure where that leaves us, but those are some thoughts.

Best regards,
-- Al

02-23-11: Mrtennis
the purpose of the thread , i believe, is the elicitation of suggestions to achieve warmth.

as i have said, without an understanding of what warmth is, the question cannot be answered.

This is a valid observation, Mrtennis, but I have found this discussion informative and interesting, in spite of our failure to arrive at a single definition of "warmth."

I think the reason why a single definition of warmth is elusive is because "warmth," as a metaphorical description of sound, is not a unitary category. It is a disjunctive category, i.e., a category of the structure X or Y or Z etc.. Disjunctive categories can be unwieldy and frustrating, but they are useful under certain circumstances.

Judging from the discussion on this thread, "warmth" seems like it can refer to harmonic content, frequency response, time domain behavior, ambient cues in the recording, listening room acoustics, and probably other things I've left out. In my view, what unites all of these diverse characteristics under the common category of "warmth" is the listener's subjective experience of each of them as "warm."

This heterogeneous definition of warmth leaves something to be desired in terms of conceptual Law and Order, which I normally find very appealing. But I suspect that, in this case, a heterogeneous definition is as good as we're going to to get.

What seems to follow from the the apparent fact that there are different KINDS of warmth is the likelihood that there are different WAYS OF ACHIEVING warmth, which is something I have learned from reading this thread.

Bryon

http://www.stereophile.com/reference/50/index.html

the fact that a word is defined does not rule out the possible arbitrary nature of the word. i am not saying holt's definition is not valid, but like any word in the english language, the duration of its usage and acceptance in communication is afctor in its utility.

by the way, what is the source of gordon holt's definition. does anyone have a reference for the definition.

perhaps if enough people accept the definition and when mentioning the word accept gordon holt's definition , it should be sufficient.

only a few people have cited holt's definition, so it seems that his definition may not be definitive.

for example, is the originator of this thread eliciting suggestions as to attain what holt defines as warmth ?

02-21-11: Almarg
…the system can certainly, as I see it, CREATE a harmonic, as a distortion product of the fundamental frequency of the note, irrespective of the existence of that harmonic in the original signal.

02-22-11: Kijanki
Harmonic distortion measurement is done by feeding pure fundamental with no overtones (sinewave) and subtracting the same fundamental from the output. Whatever remains are harmonics introduced by electronics that weren't in the original (source) signal.

The comments above are what I had in mind when, on 2/12, I wrote:

If the warmth is on the recording, and you hear it at the listening position, then the playback system is accurate with respect to warmth. Hence it is not an ADDITION. If, however, warmth is not on the recording, but you still hear it at the listening position, then the playback system is not accurate with respect to warmth. In this case, warmth is an ADDITION to the signal introduced by the playback system.

It is probably safe to say that all equipment is additive, but some equipment is more additive than others, at least with respect to the addition of harmonic content. The evidence for this can be seen in the the kind of measurements that routinely appear in Stereophile, such as Amp A and Amp B. As you can see from the graphs, Amp B adds harmonics of considerably greatly amplitude than Amp A. Hence, with respect to harmonic content, some equipment is more additive than others.

Amp A – the one with less added harmonics – is the Pass XA30.5, which is what I currently own. Amp B – the one with more added harmonics – is the PrimaLuna DiaLogue 7. The upshot of all this is that, in light of my desire for additional warmth, maybe I chose the wrong amp.

Moving on to…

The issue of whether instrument timbre is reducible to harmonic content. I am completely out of my depth here, so will remain agnostic. Having said that, IF instrument timbre is EVEN PARTIALLY reducible to harmonic content, then it reveals a flaw in the “additive approach” to playback.

Here is how I characterized the “additive approach” in a previous post…

02-12-11: Bryoncunningham
I have recently come to believe that some "additions" to the signal introduced by the playback system, while inaccuracies relative to the recording, may nevertheless be MORE accurate relative to the live event. That is because, both deliberately and accidentally, the recording process often REMOVES characteristics like warmth from the recording. Hence the ADDITION of warmth by the playback system actually makes the sound at the listening position closer to the sound of the live event.

And here is the flaw in this approach…

What is ADDED during playback will not be identical to what was SUBTRACTED during the recording process.

The reason is because, while the harmonic contents of live events are almost infinitely VARIABLE, the harmonic “additions” of playback equipment are largely CONSTANT, being persistent artifacts of a circuit's more or less fixed parameters.

Does this mean that I am retreating from my newly acquired view about the value of the additive approach to playback? No. I am merely recognizing a limit to the additive approach, namely that it cannot replace EXACTLY what is missing from the recording. Hopefully it can replace an approximation of what is missing. And that will have to be good enough.

Bryon

The definition of warmth in audio as defined by the person who introduced the word to the lexicon of audiophiles is in this thread; see J. Gordon Holt. I suggest the following: it has been used for decades. If the definition is clear, then there is little reason to tinker with it. If we need new words to describe something similar, let's find new words, and not confuse them with existing terminology. If the existing definition doesn't agree with ones interpertation, too bad, find a new word for what your trying to convey, no reason to muddy the waters with more confusion. If the definition is unclear, that's something else.

Hi guys - great posts. @Kijanki - thanks for the jitter discussion. And yes, timbres of instruments are extremely complex. It makes for fascinating reading; the book I mentioned before is a great place to start - non-musicians would have no problem with any of the terminology, from what I remember of it.

@Kirkus - thanks for the great post! I had a girlfriend in college who was doing alot of composing in the electronic music studio, and was actually quite frustrated by the bewildering array of options. It was a very overwhelming experience for her. To be honest, I'm really not very enthusiastic about any form of electronic music - while I appreciate it, I just don't care for the timbres. But you are probably right that that would be a good source of info.

About your last paragraph on poor tone production affecting tuning - what you say is basically correct, and it does go for brass instruments as well. An unfocused sound will also not necessarily be flat - the pitch actually fluctuates quite a bit, and can be sharp just as well as flat, which is a very interesting phenomena. Uncentered might be a better description of what I mean specifically here - the pitch is wandering out of the player's control, and it doesn't just move in only one direction when this happens. Pitch tends to raise, for instance, particularly when the player is straining. Overall, though, the timbre of a very unfocused sound will be dull (which is why it often sounds flat even when it may actually be sharp in pitch), weaker, and often airy in the case of wind instruments. There will also be lots of "fuzz" on the edge of the sound. Some jazz musicians cultivate this type of sound for expressive purposes, and bend the pitch quite a bit. This is where the old tuning joke "close enough for jazz" originates. Another example would be of a brass player with alot of "edge" to the sound - they may sound very loud up close, but "edge" will not carry out into the hall very well on it's own - there must be a good core to the sound.

As Mr. Tennis brings up, though, how all this relates to what audiophiles call "warmth" is another question. Even if "warmth" is called a "coloration", I think Bryon is right in asking is this a bad thing? In the case of an orchestral recording, equipment that makes the sound "warmer" is almost certainly also making it more lifelike, or as Bryon would put it, faithful to the original event. I for one don't care how a piece of equipment measures, or if it is "neutral." For me, equipment that is usually described as "warm" almost always sounds better than equipment specifically described as "neutral." And then there is the recording and how (and where) it was done. To me, these are still huge factors in the perception of "warmth," despite my education I have here received on electronics, and my realization that they do manipulate harmonics quite a bit more than I understood.

all of the discussion regarding harmonics is useful and instructive, but does not address the question of whether warmth is a form of coloration. unfortunately, no one has definitively spoken on this subject.

Well, er, if "warmth" is imparted upon the timbres of instruments to a degree not present on the recording, then yes. Otherwise, no.

To "add warmth" at the studio or FOH console, I would usually first reach for a band of EQ in the 1500-2000 Hz range, moderate-to-wide Q, and cut a couple of dB. Another technique that works in the studio is to cut the upper bass (200Hz-ish centered) area in the side chain of a compressor -- this makes it a function of envelope as well as timbre, and can add "bloom" to drums and vocals.

Does that help?

all of the discussion regarding harmonics is useful and instructive, but does not address the question of whether warmth is a form of coloration. unfortunately, no one has definitively spoken on this subject.

the purpose of the thread , i believe, is the elicitation of suggestions to achieve warmth.

as i have said, without an understanding of what warmth is, the question cannot be answered.

i have proposed an (empirical) concept of warmth as deflections in spl, both positive and nagative, which are audible. as such such a concept would connote that warmth is coloration.

let me give an example.

several posters have mentioned instruments such as the violin and flute, in their discussion of harmonics.

suppose one considers the harpsichord.

if the sound of a harpsichord seems to emphasize the wood body and to some degree, obscures the articulation of the strings, i would say the impression of the sound of the harpsichord would include warmth, as one of the adjectives used. of course, the performer might be responsible for this effect, but that is another question.

i believe the warmth region comprises frequencies below 100, so it would seem that a peak in the region below 100hz (??? how many db) would produce warmth that the poster may be seeking.

What is particularly interesting to me is your discussion of different amplitudes of the harmonics having such a big effect. I am starting to come around, but it would be good to find some info on that in particular. That would certainly seem to be one of the biggest differences between live and recorded sound, then, and probably a much bigger difference than I have thought.

For a bit more background, I'd recommend that you do a bit of reading on the theory and history of electronic synthesizers and speech synthesis. In electronic music composition, this timbral relationship between the fundamental and its harmonics is commonly referred to as "formant", the change of parameters across the duration of a note is called "envelope", and the periodic change within a note is called "modulation". Approximate, crude parallels to acoustic instruments are that formant = timbre, envelope = articulation, and modulation = vibrato.

It is of course possible for analog electronics to generate their own harmonics - this is how analog synthesizers work. I've personally implemented patches on early synthesizers (ARP and Buchla) that can deliver pretty convincing flute, bell, and string sounds. Ironically, it's not so much the timbre/formant that's hard to emulate, rather it's the envelope.

Even earlier, the acoustic principles of building formants are very structured in a thousand or so years of the art of building and tuning pipe organs. Emulation of orchestral instruments became a very common goal - this style of organ-building probably reached its zenith in the very early years of the 20th century with builders such as Willis in the U.K. and E.M. Skinner in the States.

An interesting side note on timbre - I have found it a commonly-held view in vocal and woodwind pedagogy that poor tone production produces a set of overtones that are in fact not in tune with the fundamental, rather they tend to be flat. Although I have not seen any measured evidence to back this up, I tend to agree with it - as the perception of intonation problems as it relates to tone production cannot be corrected simply by raising the pitch. That is, some singers always sound flat, no matter what pitch they're singing.

Learsfool - jitter is a form of modulation. It creates in frequency domain sidebands of very low amplitude - still quite audible since not harmonically related to fundamental. This amplitude (order of <-70dB) is proportional to level of fundamental frequency. With many frequencies (music) it becomes many sidebands - hash (noise). This noise is proportional to level of the signal and is zero with no signal - therefore is detectable only as a lack of clarity. Everything affected by noise (clarity and imaging) will be affected by jitter.

By reading this thread and some internet articles I realize that complexity of instruments' sound is something that I will never understand. One article even mentioned that bassoon at low and high notes sounds like two different instruments. In addition to complex harmonics (first five harmonics stronger than fundamental) it has pipe resonances that are getting sharper going up, resulting in "11th resonance hitting 12th harmonic". Incredible complexity - and there is still effect of the hall and technique of the player. One article mentioned interaction between instruments and gave example of two people whistling two frequencies 204Hz and 214Hz. Bystander will hear just one frequency 209Hz (average) with loudness modulated at 10Hz (difference). Orchestra has perhaps many interactions like that but produces nice harmonics. I should read on theory of music to understand it better.

Hi guys - Kijanki, you make a very good point about jitter (and explains yet another reason why digital has never sounded as good as analog for me), and the intermodulation distortions. I guess I thought that jitter had more to do with timing, but I suppose that it would indeed produce harmonic distortion as well.

Al, I do understand now much more where you are coming from, thanks very much! I will have to read up on these types of electronic distortions some more. When I took a graduate level acoustics course, it was geared (as was the very fine textbook which has always been my main reference ever since) to performing musicians and live acoustics, not recordings and electronic equipment. In fact, I am not sure that purely electronic distortions were discussed at all, I will have to look that up. I have never been one to judge audio equipment by the specs, anyway, so these types of things have never held much interest for me. This discussion has certainly got me curious, though!

I will have to check out the article you linked when I have some more time to give it serious attention. Just reading over your quotes from it, it seems like very good info. The text I mentioned goes into great detail about all of those issues mentioned. If you care to look it up, it is entitled The Musician's Guide to Acoustics, by Murray Campbell and Clive Greated, and was published by Schirmer. I do see, getting it out, that the last couple of chapters discuss electronics briefly (I think mostly from the perspective of electronic instruments rather than audio equipment, though), but the book is basically about acoustic instruments and how they behave, and how the room affects them. So my knowledge of acoustics is much more in that line, things that affect live performance rather than recording playback.

What is particularly interesting to me is your discussion of different amplitudes of the harmonics having such a big effect. I am starting to come around, but it would be good to find some info on that in particular. That would certainly seem to be one of the biggest differences between live and recorded sound, then, and probably a much bigger difference than I have thought. Thanks so much for sharing your knowledge - between you and Atmasphere in particular, I have received quite an education on this site.

Following up on my previous post, I found this excellent writeup:

http://www.phys.unsw.edu.au/jw/sound.spectrum.html

It appears that I was partly right, but not seeing the whole picture. Some excerpts from the writeup:

If you change a sound without changing its loudness or its pitch then you are, by definition, changing its timbre. (Timbre has a negative definition - it is the sum of all the qualities that are different in two different sounds which have the same pitch and the same loudness.) One of the things that determines the timbre is the relative size of the different spectral components....

Let's look between the harmonics. In both of the examples shown above, the spectrum is a continuous, non-zero line, so there is acoustic power at virtually all frequencies. In the case of the flute, this is the breathy or windy sound that is an important part of the characteristic sound of the instrument. In these examples, this broad band component in the spectrum is much weaker than the harmonic components. We shall concentrate below on the harmonic components, but the broad band components are important, too....

Introductory physics text books sometimes give the impression that the spectrum is the dominant contribution to the timbre of an instrument, and that certain spectra are characteristic of particular instruments. With the exception of the closed pipes mentioned above, this is very misleading. Some very general or vague comments can be made about the spectra of different instruments, but it is not possible to look at a harmonic spectrum and say what instrument it comes from. Further, it is quite possible for similar spectra to be produced by instruments that don't sound very similar. For instance, if one were to take a note played by a violin and filter it so that its spectrum were identical to a given spectrum for a trumpet playing the same note, the filtered violin note would still sound like a violin, not like a trumpet.

Here are some general statements about spectra:

* bowed strings and winds have harmonic spectra
* plucked strings have almost harmonic spectra
* tuned percusion have approximately harmonic spectra
* untuned percusion have nonharmonic spectra
* the low register of the clarinet has mainly odd harmonics
* bowed strings have harmonics that decrease relatively slowly with frequency
* brass instruments often have spectra whose harmonics have amplitudes that increase with frequency and then decrease.

To say anything that is much more specific than that is misleading.

The rest of the writeup is quite interesting as well, and even provides a good deal of additional specific discussion concerning the flute.

Best regards,
-- Al

Learsfool,

The basic difference in timbre between a flute and a violin, to use your example, is that one is made of metal and one is made of wood, not to mention the fact that their sounds are created in a completely different manner as well. This is obviously the largest factor in the difference in timbre. Without going into the science of it, waves produced by a string behave very differently from waves produced by a tube. A tube with one end closed behaves differently than one open at both ends, and conical and cylindrical tubes behave differently as well. Side holes in the tubes have their effects as well, of course. Not to mention different types of wood or metal alloys used in the instrument's construction, which have very great effect on the timbre.

I think that in order for our understandings to converge, what is needed is a description of the differences in spectra that RESULT from the differences you are describing. Although I'm not sure that any of us can provide that without further research. I may try to do some research on that if I get a chance tonight or tomorrow.

If a violin and a flute were to play notes having the same fundamental frequency, the same volume, and the same duration, and if their respective notes as captured by a microphone were fed into a spectrum analyzer (a device which shows the frequency components of a signal, and the amplitudes of each of those components), what would the differences be between the two spectra, that account for their very different sounds? That is the key question, as I see it.

Electronic distortion cannot introduce or create new harmonics, it can only distort those already present.

Although it may not have been your intention, this statement would seem to imply that a distortion component at a given frequency would not be added by the system were it not for the presence in the original sound of a harmonic at that same frequency. Which is not the case, as I and Kijanki (whose post I am in full agreement with) indicated.

Although some of these various timbres are more acoustically complex than others, the overtone series for all of them is always the same - it doesn't matter what instrument is creating it.

Their frequencies are always the same, for a given fundamental frequency. But the amplitudes of each overtone in the series will be very different for different instruments.

The flute happens to be one of the purest instrumental timbres.

Yes, which I think corresponds to its notes having less harmonic content than in the case of most other instruments. I.e., its notes come closer to being a pure sine wave than those produced by other instruments (although of course they are still considerably different than a pure sine wave). Which I think is a basic reason that a flute, when not well recorded and reproduced, can often tend to be "hard" sounding.

Another word on the audibility of these harmonics....

To clarify, I certainly do not assert that individual harmonics are readily perceivable. What I believe is that differences in harmonic structure (the amplitudes of the harmonics, relative to the amplitudes of other harmonics and to the amplitude of the fundamental) are the primary determinant of timbre and tone. Therefore when we perceive differences in timbre and tone, we are perceiving the EFFECTS of differing harmonic structures.

Best regards,
-- Al

"I am unaware of any naturally occuring 'harmonics' in an electrical signal. Only distortion of what ever type."

Harmonic distortion measurement is done by feeding pure fundamental with no overtones (sinewave) and subtracting the same fundamental from the output. Whatever remains are harmonics introduced by electronics that weren't in the original (source) signal. You can call it naturally occuring harmonics (introduced by electronics). Enhancing means adding system produced harmonics to instrument harmonics. System can also introduce harmonics by intermodulation or transient intermodulation. It is also possible for system to introduce frequencies that are not harmonically related to fundamental frequency as it happens often with A/D or D/A conversion with jittery clock.

Instrument might have all overtones but they don't have to be harmonic overtones. Many instruments (like percussion) produce inharmonic overtones. System will alter the sound by adding it's own harmonics.

Hi Al - you wrote: "If you are saying that any note produced by any instrument will naturally and invariably contain frequency components of non-zero amplitude at ALL harmonic multiples of the fundamental (lowest) frequency component of the note (and I don't know whether or not that is true), then yes, that would mean in a literal sense that the system cannot INTRODUCE a harmonic that isn't already there."

Yes, this is exactly what I am saying. All of the harmonic overtones of a sounded frequency are always present in the timbre, so electronic distortion cannot introduce or create new harmonics, it can only distort those already present.

About your last statement: " For a given volume, fundamental frequency, and envelope I can't envision anything other than differences in harmonic structure that could account for differences in timbre, tone, or the basic character of the note." This is a strange statement. The basic difference in timbre between a flute and a violin, to use your example, is that one is made of metal and one is made of wood, not to mention the fact that their sounds are created in a completely different manner as well. This is obviously the largest factor in the difference in timbre. Without going into the science of it, waves produced by a string behave very differently from waves produced by a tube. A tube with one end closed behaves differently than one open at both ends, and conical and cylindrical tubes behave differently as well. Side holes in the tubes have their effects as well, of course. Not to mention different types of wood or metal alloys used in the instrument's construction, which have very great effect on the timbre.

Another important thing to point out is that although some of these various timbres are more acoustically complex than others, the overtone series for all of them is always the same - it doesn't matter what instrument is creating it.

As a side note, the flute happens to be one of the purest instrumental timbres, and the oboe is one of the most complex. This is the reason that the oboe gives the A to tune the orchestra - it's complex tone is more easily audible.

Last, another word on the audibility of these harmonics. Sometimes, it is possible for the brain to concentrate on an overtone of the tone sounded, if this frequency has already been sounded, so that the ear is aware of it. For instance, if a piano sounds A440Hz, and then the A an octave below (220Hz), it will be easier to attempt to hear the A440 overtone within the sounded A220Hz tone. This takes some training, of course, especially if one wants to try to hear more difficult overtones. There are some people who have claimed to be able to hear as many as 27 different overtones, but the vast majority of researches seriously doubt this claim - 5 or 6 at most, and that for a very highly trained ear indeed. Those types of experiments are fascinating.

Best regards to you as well, Learsfool

... For a given volume, fundamental frequency, and envelope I can't envision anything other than differences in harmonic structure that could account for differences in timbre, tone, or the basic character of the note.

Just to be sure it's clear, I should add with respect to this statement that I am referring to the directly heard sound produced by the instrument, apart from hall effects and apart from artifacts of the recording and playback processes.

Best regards,
-- Al

Hi Learsfool and Newbee,

ALL natural harmonics are always present in the natural timbre, so you can't introduce a new overtone that wasn't there before.

Let's say that a note includes a frequency component at 1kHz. In response to that 1kHz frequency component, the system may create distortion products at 2kHz, 3kHz, 4kHz, and any and all other multiples of 1kHz that are within the bandwidth of the system.

Let's take the 8th harmonic (8kHz) as an example. Whether the 8kHz distortion component that is created by the system, in response to the 1kHz frequency component of the note, constitutes an INTRODUCTION of a harmonic, or an ENHANCEMENT of a harmonic, depends on whether or not an 8kHz harmonic is already part of the sound that the instrument created.

If you are saying that any note produced by any instrument will naturally and invariably contain frequency components of non-zero amplitude at ALL harmonic multiples of the fundamental (lowest) frequency component of the note (and I don't know whether or not that is true), then yes, that would mean in a literal sense that the system cannot INTRODUCE a harmonic that isn't already there.

However, the system can certainly, as I see it, CREATE a harmonic, as a distortion product of the fundamental frequency of the note, irrespective of the existence of that harmonic in the original signal. If a harmonic already exists in the note at the same frequency as that newly created distortion product, then the natural harmonic and the artificial one would combine in some manner, depending on their phase relationship.

In your violin examples, yes, those overtones are of course part of what make differences in timbre. However, each individual one is indeed indistinguishable from the others to the ears of at least 99.9% of humans. It is not possible to tell which of those overtones are the ones that are different, in your example of two different playings of the same note on the same instrument. If I played the same note twice, at the same volume, on my horn, you would not be able to tell me which individual overtones were affected and how, and this is doing you the credit that you would be able to hear the difference in the timbre between the two at all - a great many audiophiles would not, especially if I tried to the best of my ability to make them exactly the same. And in the same case, it would have to be a VERY bad recording/system indeed that would distort them so much so that most people could hear it. These sorts of differences are MUCH more audible live and at very close range than they are on a recording.

Yes, certainly I would not be able to identify and describe the specific differences in harmonic structure that correspond to the differences in timbre that I may hear, at least without the aid of sophisticated instrumentation. But my point is this: For a note with a given volume, a given fundamental frequency, and what I'll refer to as a given "envelope" (duration, rise, decay, etc.), audible differences in timbre, tone, and even the basic character of the note (e.g., violin vs. flute) are the result of differences in harmonic structure (i.e., the relative amplitudes of each of the harmonics). To the extent that differences in timbre, tone, and the basic character of the note are perceivable, differences in harmonic structure are perceivable.

I don't see how that can be incorrect, because (for a given volume, fundamental frequency, and envelope) I can't envision anything other than differences in harmonic structure that could account for differences in timbre, tone, or the basic character of the note.

Best regards,
-- Al

Learsfool, I think you are absolutely correct. I could go on ad nauseum, but suffice it to say that I see only one term when talking about electric signals, 'harmonic distortion', with the word 'distortion' being a noun and 'harmonic' being an adjective modifying it. I am unaware of any naturally occuring 'harmonics' in an electrical signal. Only distortion of what ever type.

FWIW.

Hi Al - thanks for weighing in on this. However, I think you are incorrect when you say "Harmonics can, and to some degree inevitably will, be INTRODUCED by the system in the form of distortion products." (My emphasis) Your own examples that follow are all examples of what I was speaking of in my previous post - what you call enhancing certain harmonics via distortions (and they are good examples). However, ALL natural harmonics are always present in the natural timbre, so you can't introduce a new overtone that wasn't there before, though you can distort (or even remove) it. This is what I was trying to say in my previous post. If this statement is indeed incorrect, please explain.

One other point - in your violin examples, yes, those overtones are of course part of what make differences in timbre. However, each individual one is indeed indistinguishable from the others to the ears of at least 99.9% of humans. It is not possible to tell which of those overtones are the ones that are different, in your example of two different playings of the same note on the same instrument. If I played the same note twice, at the same volume, on my horn, you would not be able to tell me which individual overtones were affected and how, and this is doing you the credit that you would be able to hear the difference in the timbre between the two at all - a great many audiophiles would not, especially if I tried to the best of my ability to make them exactly the same. And in the same case, it would have to be a VERY bad recording/system indeed that would distort them so much so that most people could hear it. These sorts of differences are MUCH more audible live and at very close range than they are on a recording.

Learsfool, as I see it an audio system can introduce harmonics, enhance harmonics, or even reduce harmonics that may be present in the source material.

Harmonics can, and to some degree inevitably will, be introduced by the system in the form of distortion products.

They can be enhanced either by virtue of a frequency response emphasis that happens to occur at a frequency corresponding to some harmonic (multiple) of the fundamental frequency of a note, or by virtue of a frequency response dip that happens to occur at the fundamental frequency, or by virtue of distortion of the fundamental frequency of a note, the distortion products therefore occurring at the same frequencies as harmonics that may be present in the note.

They can be reduced by the converse of those frequency response effects, or by introduction of a distortion product that is out of phase with a harmonic that may be present in the note at the same frequency.

I'm just saying that there is a whole lot more to do with that than amplitudes of individual harmonics within the overall timbre - again, these harmonics are inaudible to far more than 99.9% of us.

I respectfully disagree. My understanding is that timbre and the relative amplitudes of individual harmonics are one and the same.

As I understand it, to cite an example, a violin playing a note whose fundamental frequency is say 1 kHz will produce very audible harmonics at 2 kHz, 3 kHz, and other higher multiples of 1 kHz. A flute playing a note whose fundamental frequency is also 1 kHz will produce very audible harmonics at those same multiples of 1 kHz. The reason that the note produced by the flute will sound different than the note produced by the violin is that the relative amplitudes of those harmonics will be in different proportions.

And, similarly, differences in timbre and tone between two different playings of the same note on the same instrument will be the result of differences in the relative amplitudes of those harmonics, as I understand it.

Best regards,
-- Al

Hi Bryon - perhaps Al can weigh in on this and correct me if I am wrong, but I'm pretty sure harmonics couldn't truly be "added," (they are of course all already present in the timbre) though digital reverb would be an example of an "addition" that would certainly affect the perception of warmth. Overtones can be and are sometimes removed by digital processing.

Perhaps a better word to describe what you are speaking of would be "emphasizing." Atmasphere has posted quite informatively about these types of issues, talking of even or odd order harmonics being emphasized by the design in different types of amps, and whether or not the designer is thereby following the "rules" of human hearing. This is very similar to the way the acoustical environment affects the timbre, except the designer of a piece of audio equipment I suspect has alot more control over his end result than an acoustician does.

And yes, I would say that tube designs are certainly "warmer," speaking very generally, than solid state designs, therefore sounding more lifelike. I'm just saying that there is a whole lot more to do with that than amplitudes of individual harmonics within the overall timbre - again, these harmonics are inaudible to far more than 99.9% of us.

02-17-11: Learsfool
The only quibble I still have with this discussion is with the importance many of you are placing on minute changes of amplitude in overtones within a musician's timbre as being the major factor in a perception of "warmth." (I am not denying that this is a factor)...Harmonics do of course have to do with the "warmth" of the timbre, but the MUSICIAN has no control whatsoever over specific harmonics within the overall timbre. [emphasis added]

Hi Learsfool - I may be wrong, but I think the importance many folks have given to harmonics in the perception of warmth has less to do with how harmonics are produced by a MUSICIAN and more to do with how they are reproduced by the PLAYBACK SYSTEM. In other words...

Some systems merely PRESERVE whatever warmth exists on the recording. Other systems seem to ADD warmth, whether it exists on the recording or not. For these systems, a common belief is that the added warmth is often a consequence of added HARMONICS.

Do you not think that added harmonics, as you might get with a tube amp, are a significant contributor to the perception of warmth during playback?

Bryon

Hi guys - I wrote a very long post last night, only to discover that I could not post it, for some reason. The discussion has meanwhile left me far behind, but it has been a very good one. Obviously, the main problem here is terminology. As Newbee politely pointed out, some of you seem to have a misconception of what "harmonics" or "overtones" are, and my attempts to define it were obviously unsuccessful. I refer you to any book on acoustics. Hifibri in particular has misconstrued what I have been saying about them, and I give up - there is a reason why I am a musician, and not a writer, LOL (Hifibri, if you want to email me through the audiogon system, I can try to explain to you why your guitar example is not quite correct). I am in agreement with what Al and Newbee have said about harmonics in general.

What I will say is that I think I do finally have a handle on why you all think that frequency response is a major part of warmth. The terminology was holding me back - partly some people's incorrect usage of it, but also and mainly the differences between the meaning of certain words when used in the context of a musician's performance as opposed to the attributes of an audio system's "performance." The only quibble I still have with this discussion is with the importance many of you are placing on minute changes of amplitude in overtones within a musician's timbre as being the major factor in a perception of "warmth." (I am NOT denying that this is a factor) Overtones are inaudible to 99.9% of us. Changes in their amplitude, therefore, would not be heard independently from changes in amplitude to the main frequency actually being sounded. Harmonics do of course have to do with the "warmth" of the timbre, but the musician has no control whatsoever over specific harmonics within the overall timbre. Nothing the player does can isolate a specific harmonic and change it's amplitude - all harmonics will be affected by anything happening to the main frequency being sounded. Let me give a couple of examples.

If I sound the same tone with the same amplitude on two different horns in the same room, the differing "warmth" of the instruments will have everything to do with the alloy of the metal used in constructing the instruments, as well as the difference in the way the horn is designed (not to mention the differences in execution of the same design). Assuming that a strobe tuner is present so we can be sure that the two tones are of exactly the same frequency, the harmonics will be exactly the same. And if the frequency is off by say a cent or two, the harmonics will be proportionally off as well, and this extremely slight difference would not be perceived by 99.9% of us, anyway. You would perceive perhaps a great difference in the "warmth" of the two horns, but it is not because of harmonics. Same if I play the exact same frequency and amplitude in two different rooms on the same horn. They WILL sound perceptibly different to everyone, but it is because of the acoustics of the room, not because of overtones. One more example - two different recordings made of one note in the same room (with a different mike placement for each, or very possibly with the same mike placement) will also sound different. One may sound "warmer" than another, but again not because of harmonics.

Bryon, you are definitely on the right track here: "some acoustical environments, whether a recording space or a listening space, can CONTRIBUTE to the perception of warmth, while other acoustical environments can DIMINISH the perception of warmth. The fact that most concert halls - being highly acoustically designed environments - contribute to the perception of warmth is something I do not take issue with. I was merely trying to point out that LESS WELL DESIGNED acoustical environments might diminish the perception of warmth. Two things seem to follow from that observation. First, for recordings that lack warmth, the acoustics of the recording space might be a factor. Second, for systems that lack warmth, the acoustics of the listening space might be a factor." Change the first word from "some" to "all," and change each use of the words "can" and "might" to "will". Despite all the best acousticians know, it is impossible to predict exactly what the hall is going to do to the overall sound. These factors and others mentioned in other posts (the audio equipment itself, in particular) have a great deal more to do with "warmth," IMO.

02-16-11: Newbee
Tubes. If you have speakers appropriate to your room and to tubes in the first place, and these speakers have a reasonably good sense of 'natural' resolution, by using tube equipment and carefully using (rolling) tubes therein to get you to your sonic goals, you can tame common HF problems and even add some bass /lower mid range boost (that warmth you are looking for?).

I think this is good advice, Newbee. I just listened to some tube amps tonight - a Jadis and a VTL. One warm, the other less so. The warm one portrayed instrument timbres beautifully, but unfortunately it was dynamically challenged, to put it politely. I will continue to listen to tube amps...I am really a novice here.

02-16-11: Mapman
Many feel some speakers are "warmer" sounding than others...
I'm wondering do different speaker designs handle harmonics differently? that would seem to be the case if harmonics is the main factor in determining warmth.

I agree that some speakers sound warmer than others. I assumed that was a consequence of differences in frequency response, cabinet coloration, and/or high Q drivers. But you may be right that there are differences in the harmonic characteristics of speakers. If so, I wonder what determines a speaker's harmonic "signature"?

02-16-11: Mrtennis
it would be interesting to find out rrobert harley's definition from his famous book (i don't remember the title).

The term "warm" does not appear in the glossary of RH's Guide to High End Audio. It does appear in a section called "Sonic Descriptions and their Meanings." He does not explicitly define "warm," but he seems to use it to mean "harmonic accuracy." FWIW.

Bryon

Hi Mr T,

As I have said in a post previous to the one you have quoted, my only hope when I listen to recorded music is to hear something that sounds natural, consonant with that which I would experience live. My live experiences leave me with little choice when selecting components for my home system but to tune a system which might be called warmish, especially in the upper bass/lower mid's and a little dip between 2 and 3K hz. I do not seek a reduction in the high frequencies. To me my choices only compensate for the prevailing design critera used by so many speaker and electronic's manufacturers, as well as more than a few recording engineers that better serve the stereo format and goals than the music itself. Just think how music could be better served if soundstage was no longer an issue. In stereo the engineers rely on multi-mic'ing to create the stereo effect and the sound of a live event is lost.

For example, most live music, except for very close seating is mono in form which is amplified by the horn shape of the stage and enlarged by the hall acoustics. If you can ever find one, try a properly set up binaural recording and see how much the stereo soundstage collapses into a large, well defined, mono sound field.

FWIW, just my POV. But I don't think I can help you with your conclusions.

Call that sound colored if you will but to me it has the potential to occasionally remind me of something I heard live, and at worst covers a lot of 'uncolored' sin perpetrated in the name of 'audio'.

hi newbee:

i think you have described the concept of warm, in your first paragraph in a previous post.

however, would you say that a dip in the highs and a peak in the upper bass and/or lower mids, is amore specific description of warmth ?

if so, warmth is a coloration--an audible deviation from a flat frequency response.

a basic issue is whether warmth is a coloration.

as 9i have said, when listening to musicians playing instruments which are unaplified, does the word warmth apply ?

i think not, i suspect that what people mean by warmth is accuracy of timbre. when an instrument does not sound real, there usually are errors in frequency response.

it would be interesting to find out rrobert harley's definition from his famous book (i don't remember the title).

the easiest way to achieve warmth , other than room treatment is equalization, but there is a cost to using this approach. i had suggested a deqx or tact in a previous post, these devices operate in the digital domain.

Mapman, FWIW, I agree with your first two sentences. I think tonal differences in speakers can easily be effected by enclosure design, speaker selection, and crossover design.

Except for those speakers which have been intentionally designed to use its natural resonance frequencies to enhance a tone, the speakers 'harmonics' would not greatly affect its frequency response so much as its resolution.

For example, if the cabinet had an unsuppressed resonance frequency of, say 350hz, it would likely sound muddy/boomy, not natural at all, and something I think a designer would want to avoid like the plague.

In the context of this thread I think 'harmonics' is a term referring to the overall tone of an instrument and how it is replicated in the recording or playback process, something that it best appreciated with the choice of a violin, guitar, piano, etc, which all have sound boards which resonate and create complex sounds (harmonics) resulting in a natural tone. Not a warm tone, not a cool tone, a natural tone, the signature of the instrument itself, and not the recording or playback process. That tone is what it is. That is what I think when I use the term 'natural'.

Personally I'm not comfortable in referring to speaker designed tone, hall acoustics, or home room acoustics as 'harmonics' in the same sense as those of instruments.

Many feel some speakers are "warmer" sounding than others.

I have always tended to attribute this to tonality, ie the relative balance of frequencies with warmer speakers tending to have less emphasis on treble or higher frequencies relative to midrange in general.

I'm wondering do different speaker designs handle harmonics differently? that would seem to be the case if harmonics is the main factor in determining warmth.

Most discussion of harmonics I have read tend to be about how different amplifier technologies deal with harmonics.

But what about speakers then assuming some speakers are inherently warm and others less so, which I believe to be the case.

Bryon, Re Room treatments/tuning, like everything else in audio, ain't a Sunday walk in the park with a pretty girl.

Depends on what you are trying to change to create 'warmth'. In this post I will assume that 'warmth' means unemphasized highs with or without a corresponding wide but small boost in the lower mid-range thru to the upper bass. Room dimensionally induced issues? Set up issues? Equipment selection issues? Treatment selection absorption/dispersive panels, traps, etc, all of which require careful selection given the source of the 'problem' are critical.

For example, excessive sounding highs can be caused by equipment types or positioning relative to reflective surfaces. They can be controlled/reduced by speaker location, orientation, or using sound dispersion or absorption panels.

But, as in the case of absorption panels, a common type of treatment recommended and used by audiophiles, if the materiel used covers a broader frequency range than needed, i.e. you need to knock down a 5K peak but use materials which are absorptive down to 1500k you will have dulled down an otherwise well balanced mid range. This might enhance the sound of the lower mid range/bass to some folks but not to all.

Conversely if you have an upper mid-range peak, a very common problem in speaker and electronics, and you try to damp it with absorption materials you loose the highs as well as the mid-range peak. For me that removes specific absorbers from the list of possibilities unless you can figure out how to compensate for the unwanted change. And so it goes with a just few room treatments but set up problems as well as speakers and electronics share the same issues. How to get balance in your room? Even the experts often can't get it right.

So, to my point (finally). Tubes. If you have speakers appropriate to your room and to tubes in the first place, and these speakers have a reasonably good sense of 'natural' resolution, by using tube equipment and carefully using (rolling) tubes therein to get you to your sonic goals, you can tame common HF problems and even add some bass /lower mid range boost (that warmth you are looking for?).

The possibilities with tube equipment seem as endless as the frustrations experienced by many in the implementation of tubes, especially by those who aren't all that dedicated and like quick fixes, or miracles. One of the things that I would always recommend because of the learning curve involved is to keep it simple, even knowing that ultimately someone might want an all tube system. For example, there are quite a few good integrated tube amps now and are an excellent place to start as opposed to introducing separates and making a mixed system.

And, FWIW, realizing that there exists those who will vehemently disagree, with ss stuff you are excluded from changing its sonic signature significantly, keeping it off the horizons for adventurers. Wires and little black boxes can only do so much.

But I digress and apologize for going off point and getting on a box with such simple observation

If a space can't support or leaks the lower frequencies, and at the same time reverberates or enhances the higher frequencies, though not typically likely to happen, I would suspect the results would be "cool".

02-16-11: Unsound
"...While other hall effects might sound cool". Yes, but I would think that's more likely in small, highly reverberant halls, and not as likely to happen in typical concert venues.

02-16-11: Almarg
I can't remember ever being in a hall in which the instruments sounded "cool," in the way that they can on some recordings.

My apologies. I wasn't very clear in my last post. When I used the phrase "hall effects," I intended to refer to the acoustical characteristics of recording spaces that might or MIGHT NOT be a concert hall. In other words, I intended "hall effects" to simply mean "acoustical effects," and I should have said as much.

What I was trying to express was the idea that some acoustical environments, whether a recording space or a listening space, can CONTRIBUTE to the perception of warmth, while other acoustical environments can DIMINISH the perception of warmth.

The fact that most concert halls - being highly acoustically designed environments - contribute to the perception of warmth is something I do not take issue with. I was merely trying to point out that LESS WELL DESIGNED acoustical environments might diminish the perception of warmth. Two things seem to follow from that observation. First, for recordings that lack warmth, the acoustics of the recording space might be a factor. Second, for systems that lack warmth, the acoustics of the listening space might be a factor.

Bryon

Learsfool you wrote; "As I have tried to explain, the actual overtones do NOT change"....and; "Al, you are probably correct about the amplitude of them (overtones) changing". If they change amplitude, they change the sound and waveform, change is change. If a musician strums an open chord on an acoustic guitar, then the musician places his hand on the bridge and strumms the same chord it would sound different because the frequency and amlpiude of the overtones have changed due to the damping effect of the musicians hand. It's basic acoustics.

All halls, venues, rooms have thier own sound.
http://classicalmusic.about.com/od/concerthallsvenues/ss/bestconcerthall_6.htm

Often they are modified to improve thier sound.
http://www.saflex.com/pdf/Saflex%C2%AE%20Acoustic%20-%20Chicago%20Symphony%20Orchestra%20Hall.pdf

RE: Time domain behavior. Earlier on the thread, Newbee said something similar - that warmth is partly a matter of a system's ability to portray the decay of notes. I suspect you mean something similar. Do you think that tubes are inherently better at this?

I would not go so far as to say that tubes are inherently better with respect to time domain performance. Their main advantages, as I see it, relate to harmonic balance, and also to increased dimensionality and better imaging (although as I indicated earlier, I can't explain technically why that would be so).

However, tube designs lend themselves more readily to minimal use of feedback. As Atmasphere has frequently pointed out, feedback, at least if not done judiciously, can create or enhance objectionable distortion components. It can also affect the quality with which the leading edge of rapidly changing transients are reproduced. Our hearing mechanisms give particular emphasis to those leading edges, as a result of the Haas Effect and the Precedence Effect. Although as was stated in Newbee's excellent post, that is most applicable to instruments whose notes have fast risetimes. His comments about decay times I also think are very true.

It seems plausible that the indirect sound from a recording space might contribute to the perception of warmth.... But that also seems to imply that, under some circumstances, flawed recording spaces might diminish the perception of warmth. In other words, some hall effects might sound warm, while other hall effects might sound cool. Do you think that's true?

I would doubt it, at least assuming the hall is at least semi-decent. I can't remember ever being in a hall in which the instruments sounded "cool," in the way that they can on some recordings.

In a hall, I just about invariably sense a sort of "aura" surrounding each note (more so or less so depending on the instrument and the music, of course), that contributes to a sense of richness/body/warmth, and which I believe is a result of the summing together of delayed sound and directly heard sound.

... Hence there might be ways to increase the warmth of a system through acoustical treatments in the listening room, which is an interesting idea to me.

Room acoustics and treatments are not one of my areas of expertise, but my instinct, with respect to situations where physical and aesthetic considerations are not too limiting, would be that it should often be possible to find a compromise that would enable "cold" recordings to be warmed up somewhat, without significantly degrading reproduction of good recordings. But only to a limited extent, given the disparities in delay times between listening rooms and halls.

Best regards,
-- Al

"...While other hall effects might sound cool". Yes, but I would think that's more likely in small, highly reverberant halls, and not as likely to happen in typical concert venues.

02-13-11: Almarg
...realistic reproduction of timbre, which as I see it correlates with accurate reproduction of the RELATIVE amplitudes of the harmonics and the fundamental of each note, as well as proper time domain performance and ambience reproduction, I envision as being the keys to the PROPER reproduction of warmth.

RE: Harmonics. I agree with you completely that the relative amplitudes of harmonics are a significant factor in the perception of warmth.

RE: Time domain behavior. Earlier on the thread, Newbee said something similar - that warmth is partly a matter of a system's ability to portray the decay of notes. I suspect you mean something similar. Do you think that tubes are inherently better at this?

RE: Ambience. As I mentioned in a previous post, it never really occurred to me that ambience was a significant factor in the perception of warmth. That is probably because I have a number of studio recordings with no "hall effects" that nevertheless sound warm to me.

Having said that, it seems plausible that the indirect sound from a recording space might contribute to the perception of warmth, whether from the kind of "frequency contouring" you alluded to or from other effects. But that also seems to imply that, under some circumstances, flawed recording spaces might diminish the perception of warmth. In other words, some hall effects might sound warm, while other hall effects might sound cool. Do you think that's true?

I should add that if the indirect sound from recording spaces can affect the perception of warmth, for better or worse, then it seems to follow that the indirect sound from listening spaces might also affect the perception of warmth, for better or worse. Hence there might be ways to increase the warmth of a system through acoustical treatments in the listening room, which is an interesting idea to me.

Bryon

Hi guys - Hifibri wrote in his last post "By changing overtones you change the shape of the wave and the resulting sound." As I have tried to explain, the actual overtones do NOT change.

Al, you are probably correct about the amplitude of them changing, I would need to get out my acoustics books to make sure. However, since these overtones we are speaking of are not audible to the vast majority of even highly trained ears, changes in their amplitude then would not be audible either, and they would be very minute in any case (though some would argue that this does not mean the brain wouldn't perceive the change somehow). The actual amplitude of the total sound of course has a far greater effect on the waveform. You bring up a very interesting question, though. How a musician's subtle changes in timbre affect the waveform is something I would need to look up (certainly these changes obviously effect the waveform somehow) - but I am not sure that my books go into that much detail. What I can say is that there is no way a musician can deliberately change the volume of a specific overtone in his sound, so even if you are completely correct, there is unfortunately no practical application of this for actual live performance.

Regardless of what the answers to these questions are, things like what Al terms "hall effects" have a MUCH greater effect on the perception of "warmth" (Unsound is perfectly correct in his last post), and the recording itself has an even greater effect. The design of the audio equipment also has much to do with it - for instance, to bring up Onhwy61's point, many designers of digital processors routinely omit all harmonics above the range of human hearing, claiming what the ear can't hear it won't miss. Many of us beg to differ, and it has been proven that the brain can detect frequencies above what the ear can hear. LOL, am I now getting dangerously close to arguing against my point? This is a fascinating discussion, indeed.

FWIW, I think that when we attend many concert halls, especially large ones with many patrons, we are often exposed to "warmth". The same instruments can sound quite different; without an audience, in different rooms or even in different seats. Depending on your perspective "warmth" can be either natural or a by-product of a typical live listening experience.

Onhwy61, Yes, audiophiles used the term 'warmth' before the 'advent' of digital. :)

Almarg, Thank you for your explanation. I am in full agreement. By changing overtones you change the shape of the wave and the resulting sound. The most basic example is the sine wave and square wave at the same frequency.

As the OP indicated there are many factors that can contribute to the perception of warmth, none ‘better’ than the others. Some types can be good when they compensate for deficiencies elsewhere is a system, everything is a synergistic balancing act.

The term ‘warmth’ can be used to describe sound as being additive, subtractive, and a component of a neutral sound. Scientists who study such things will tell you that there is no such thing as cold, only the absence of warmth. An analogy using the most common meaning for the word warmth would be to determine an ideal room temperature, say 70 degrees. This would be your 'neutral' or live sound reference. By subtracting warmth you would cool the room, by raising the temperature you would warm it, but the ideal would still possess ‘warmth’. We can apply the term ‘warmth’ to describe a range of sound in the same ways. If a sound is cool, it lacks warmth and is unnatural. If it sounds neutral it has just the right amount of warmth and sounds natural or neutral. If it sounds too warm, then it is unnatural. Warmth can be used to describe naturalness of timbre.

We agree on the basic sonic character of ‘warmth’, but being an adjective, it can be used to describe a wide range of that character, both very minute, and very large differences. Therefore, it is the responsibility of the person using the word to ensure that the description of the degree of warmth is understood by the audience. The exact definition of any word will never overcome sloppy usage.

A slight clarification to my previous post:

In referring to ambience, my intent was to refer to the totality of hall effects, rather than to the sense of "air" with which that term is commonly associated, "air" primarily involving high frequency effects (as was stated earlier by others).

In fact I should probably have used the term "hall effects" instead of "ambience." I'm referring to the totality of the complex interplay that occurs in a hall between directly heard sound, and reflected sound that has been both frequency contoured and delayed by multiple increments of time. All of that, as I have perceived it in my concert-going experience, is a key factor in perceived sonic "richness," which I (and others earlier in this thread) correlate with "warmth."

Best regards,
-- Al

A question and a follow up -- did audiophiles talk about "warmth" prior to the introduction of consumer digital audio? And if they did, does "warmth" mean the same thing in each time period?

This thread has certainly evolved, as might be expected considering the parties who are participating, into a really excellent dialog.

FWIW I must very respectfully say that at this point I agree with Hifibri and I disagree with Learsfool. I see it as follows: Yes, the FREQUENCIES of all of the harmonics are determined unalterably by the fundamental frequency (i.e., the lowest frequency component) of the note that the musician chooses to play. However, wouldn't the individual AMPLITUDES of each of those harmonics, relative to the amplitudes of the other harmonics and to the amplitude of the fundamental, vary depending on the waveform changes you agree can occur?

If not, what would a spectrum analysis of the waveforms indicate is changing? I doubt that extraneous or spurious frequencies are being introduced, that are not harmonically related to the fundamental. What could be changing, that would account for the waveform changes, other than the relative amplitudes of the harmonics and the fundamental?

And if the waveform changes are in fact in the form of alterations of that harmonic structure/balance, then doesn't it stand to reason that there is a relation between "warmth" and harmonic structure/balance?

I do think it is very much an oversimplification, and a common audiophile misconception, to speak of warmth as just being a frequency response that is non-flat in some way. A mid-bass peak, or some similar frequency response emphasis, might contribute to a subjective perception of warmth. But realistic reproduction of timbre, which as I see it correlates with accurate reproduction of the RELATIVE amplitudes of the harmonics and the fundamental of each note, as well as proper time domain performance and ambience reproduction, I envision as being the keys to the PROPER reproduction of warmth.

Best regards,
-- Al

Hi Bryon - loved the beginning of your post. :) I think we are actually in agreement here.

@Hifibri - yes, re-reading what I wrote, that is a little confusing, for which I apologize. Basically, this is the part that is the important part: "the main point is that the musician CANNOT (emphasis added) change the natural overtones produced by the frequency being played." In this quote: "Now, if the player’s tone is not pure…this CAN (emphasis added) mess with the overtones…musicians sometimes deliberately bend notes on purpose." the word "overtones" is not what I meant to use - I meant to say frequency, though this is pretty badly worded period.

Without going into a very technical discussion of sound waves and how they are formed inside a brass instrument (to continue your example), a brass player is manipulating frequency and creating different waveLENGTHs when he "buzzes" his lips as the air moves through them and into the instrument. Where this frequency is on the natural harmonic series determines the waveLENGTH. These natural harmonics are of course fixed, as are the resulting overtones in the sound, which are determined by these fixed natural harmonics. It isn't possible for the player to manipulate these. If the player is "lipping" too much or too little, or "blowing" too much or too little, this inefficiency results in the tone becoming unfocused in some way, changing the waveFORM, but it does NOT change the frequency or the waveLENGTH, and therefore does NOT change the harmonic content. The dynamic level, or amplitude, makes subtle changes to the waveFORM, and any subtle "color" changes the musician may make to a note (such as the jazz trumpet player "bending" a pitch) also change the waveFORM, but NOT the harmonic content.

So the point I am leading to here is that changes in "warmth" are NOT related to frequency or harmonics or overtones whatsoever. I hope the above is clear, there is a reason I am a musician and not a writer! So to speak of "warmth" in a system as something to do with frequency response seems wrong to me, and I am trying to understand this association among audiophiles.