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
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
"...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.
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
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
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