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

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 ?

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

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

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