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


Many audiophiles set out to assemble a system that sounds “warm.” I have heard several systems that could be described that way. Some of them sounded wonderful. Others, less so. That got me wondering: What is this thing called “warmth”?

It seems to me that the term “warm” can refer to a surprising number of different system characteristics. Here are a few:

1. Harmonic content, esp. added low order harmonics
2. Frequency response, esp. elevated lower midrange/upper bass
3. Transient response, esp. underdamped (high Q) drivers for midrange or LF
4. Cabinet resonance, esp. some materials and shapes
5. Room resonance, esp. some materials and dimensions

IME, any of these characteristics (and others I haven’t included) can result in a system that might be described as “warm.”

Personally, I have not set out to assemble a system that sounds warm, but I can see the appeal in it. As my system changes over time, I sometimes consider experimenting more with various kinds of “warmth.” With that in mind…

Do you think some kinds of warmth are better than others?

Thanks for your thoughts.

Bryon
bryoncunningham
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.
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 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 ?
02-23-11: 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