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

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.

Onhwy61, Yes, audiophiles used the term 'warmth' before the 'advent' of digital. :)

FWIW, I think that when we attend many concert halls, especially large ones with many patrons, we are often exposed to "warmth". The same instruments can sound quite different; without an audience, in different rooms or even in different seats. Depending on your perspective "warmth" can be either natural or a by-product of a typical live listening experience.

Hi guys - Hifibri wrote in his last post "By changing overtones you change the shape of the wave and the resulting sound." As I have tried to explain, the actual overtones do NOT change.

Al, you are probably correct about the amplitude of them changing, I would need to get out my acoustics books to make sure. However, since these overtones we are speaking of are not audible to the vast majority of even highly trained ears, changes in their amplitude then would not be audible either, and they would be very minute in any case (though some would argue that this does not mean the brain wouldn't perceive the change somehow). The actual amplitude of the total sound of course has a far greater effect on the waveform. You bring up a very interesting question, though. How a musician's subtle changes in timbre affect the waveform is something I would need to look up (certainly these changes obviously effect the waveform somehow) - but I am not sure that my books go into that much detail. What I can say is that there is no way a musician can deliberately change the volume of a specific overtone in his sound, so even if you are completely correct, there is unfortunately no practical application of this for actual live performance.

Regardless of what the answers to these questions are, things like what Al terms "hall effects" have a MUCH greater effect on the perception of "warmth" (Unsound is perfectly correct in his last post), and the recording itself has an even greater effect. The design of the audio equipment also has much to do with it - for instance, to bring up Onhwy61's point, many designers of digital processors routinely omit all harmonics above the range of human hearing, claiming what the ear can't hear it won't miss. Many of us beg to differ, and it has been proven that the brain can detect frequencies above what the ear can hear. LOL, am I now getting dangerously close to arguing against my point? This is a fascinating discussion, indeed.

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