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
FYI:
http://www.stereophile.com/content/sounds-audio-glossary-reverse-glossary-part-1
Hello Hifibri - I guess I am still struggling with your use of the term "warmth", after reading your latest post. You seem to be equating "warmth" with the sound of the instrument itself, not merely as a characteristic of it. For a musician thinking about his sound, the "warmth" of it has nothing to do with the frequency being produced, but has to do with the "color" of the sound, or in audio terms, proper reproduction of timbre, not frequency response. Now of course, if a system has frequency response issues, it probably won't resolve timbre correctly, so I guess I can see why you would directly associate the two. However, I would still maintain that you can have a system that measures very well in the frequency response that still sounds very cold (or doesn't resolve timbre correctly) - I have heard many of them in dealer's showrooms - so that is why I do not equate "warmth" with frequency response. Harmonic structure does come much closer to my conception.

Your definition of "air" is also different from how I have sometimes seen the term used here before - some on this board seem to associate that term exclusively with high frequencies. I like your definition better, and I agree that it is a separate thing from "warmth," though it will have a huge effect on the perception of it.
02-10-11: Learsfool
...you can have a system that measures very well in the frequency response that still sounds very cold (or doesn't resolve timbre correctly) - I have heard many of them in dealer's showrooms - so that is why I do not equate "warmth" with frequency response. Harmonic structure does come much closer to my conception.

Learsfool - I agree that a system that measures well in frequency response can nevertheless fail to sound warm. In other words, balanced frequency response isn't a sufficient condition for the perception of warmth. But that doesn't mean that balanced frequency response isn't a necessary condition for the perception of warmth.

I suspect that, to be perceived as warm, a system must have a balanced frequency response, within some range. (BTW, I don't think "balanced" is necessarily the same thing as flat.) I think that bright systems, or systems with very little bass, are less often perceived as warm. And I think that systems with elevated upper bass and/or lower midrange are more often perceived as warm. In addition, Al pointed out how anomalies in frequency response, like those created by comb filtering, might conceivably diminish the perception of warmth.

Taken together, these considerations seem to suggest that there is a link between frequency response and the perception of warmth, even though, as you point out, some systems that measure well in frequency response nevertheless fail to sound warm.

This is not just about semantics or logic. It's about HOW TO GET warmth in your system, when you don't have it. If warmth is both a matter of frequency response and harmonic content, then manipulating one of those variables could presumably contribute to the perception of warmth.

RE: The use of frequency response to increase warmth. I think efforts to balance frequency response are a good idea, whether it's done with tone controls, eq, or room treatments. I use all three, but would still like some additional warmth. One way to get it, in light of the observations above, might be to elevate the upper bass and/or lower midrange of my system. But I'm not a big fan of this idea. I tend to experience systems with elevated upper bass/lower midrange as uneven, slow, thick, or unresolving.

RE: The use of harmonic content to increase warmth. I think this is a much better idea. The obvious way to add harmonic content is to add tubes, as several posters have pointed out. Unfortunately, in my case, that would mean changing both my amp and my speakers, since my speakers aren't very tube friendly. That could get expensive, but I'm considering it.

Bryon
Bryon,

Many confuse foggy muddy systems that can only play one or two of Carol Kidd's ballads as the ultimate warm systems.

Making a system foggy and rolled off masks the lack of dynamic linearity, stability, and distortion from transients.

A tube power amp may not necessarily be warm. Listen to the recent Audio Research amps. They are anything but warm.

I listened to a pair of Electra 1027Be's a few years ago with Chinese Cayin gear and they didn't sound bad at all.
I don't think they aren't tube-friendly.

I really think you ought to try a tubed DAC and a tube preamp. Just borrow a tube preamp from a friend and see if it gets you the sound you want.
FWIW, I think someone has already touched upon one of the critical elements to the appearance of warmth in a system with balanced tone, that is the proper rise and decay of the signal without which balanced tone becomes meaningless.

IMHO proper rise and decay times, when everything else is right, is what makes good recordings sound more like the natural sound of instruments. Unfortunately this is not achieved by any add on processor, you have to get it designed into your components.

IME, the most critical time element is adequate decay. Too short a decay and the tone loses natural harmonics and sounds bright/clinical. May help superficially in creating the sense of a large soundstage, but in the long run fatigues. Too long a decay and the sound becomes muddy. Rise time is important too, but just less so I think, except for the effect it has on those instruments which have a fast/sharp rise, such as percussion instruments.

It might be important to consider how the natural harmonics of an instrument occur in the first place and what constitutes harmonics as the term applies to an audio system.

I'm not so sure equalizers or tubes are the method to be used to obtain 'warmth' if that term is not to be equated to frequency response or tonal balance. But, if your system lacks adequate rise and decay tubes and equalizers etc may be the only way.

Just a thought Bryon.