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

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.

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

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?

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

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.