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

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.

I agree with this, Al, insofar as I recognize that the harmonic content introduced by equipment varies as a function of the spectral content and level of the input signal. So perhaps "variable vs. constant" is not quite the right distinction.

The distinction I was trying to capture is between the harmonic content of the live event vs. the harmonic content of the reproduced event. To the extent that the recording process diminishes the harmonic content of the recording, the additive approach to playback may do something to replace what is missing. But it cannot, so far as I am aware, replace the EXACT missing harmonic content, since the harmonics introduced by equipment are, in essence, artifacts.

The fact that equipment-induced harmonic artifacts vary as a function of the spectral content and level of the input signal does make them "variable," perhaps even as variable as the harmonics of the live event. Nevertheless, equipment-induced harmonic artifacts are not SIMULACRA of the harmonics of the live event. That is the flaw in the additive approach to playback that I was trying to point out.

Bryon

Looking back on this thread, I have another thought...

There has been a lot of discussion about how increasing warmth in a system might involve ADDING something to the signal, like low order harmonics. It occurs to me that increasing warmth might also involve SUBTRACTING something from the signal.

Maybe the most obvious example of how subtracting something from the signal might increase warmth is subtracting treble, which amounts to the same thing as adding midrange/bass. A less obvious example is contained in Al's second post on 2/6, namely subtracting destructive acoustical effects like comb filtering. One final example that I have personally experienced is subtracting (or at least reducing) jitter in digital playback, which to my ears increases the perception of "warmth."

Bryon

“and how do you get it”… I just went to “warm” by changing the footers under my CDP from Stillpoints to HRS Nimbus Couplers. I really liked what the Stillpoints did, but at times my system sounded a little “thin”. Without losing any of the good that the Stillpoints brought, the HRS Nimbus Couplers added what can best described as “weight”.

Some times, it could be as easy as swapping the source I/c. Not to alter freq response but take that electronic tinze/noise surrounding the notes. I have three sets of cables at each source, same corresponding brand for each level of sound i desire- neutral, slightly warm and warmer. You will be surprised how 'listenable' most music would become... true changing cables every once in a while is a chore and one set of cables is always your primary choice. It is no different than some folks trying different tonearms, cart, diif DAC sampling, diff sources...

One characteristic that warmer sound gets you is the image size ( overall- fundamental and harmonics and air) of instruments become life size which I personally consider primary requisite.

In 1970, a girl who I shared a house with, had a Fisher tube receiver and a pair of KLH bookshelf speakers that were given to her by a friend. Thats the first time I experienced "warmth" which totally had me captivated. Warmth is a full, rounded, refined relaxed sound that has a silky thickness and velvet texture to the music. A more of a full body to the sound where the upper frequencies seem to bend down more and blend and integrate into the mid-bands. From that era, several factor's come into play. Tubes at the time that were made by Sylvania, Zenith, RCA, and GE, were better built then the best tubes of today. Back then they had double glass envelopes, heavier filaments, and the technical artists who made those tubes are non-existent today. They were like composer's. In fact, the hardware machines are still in existence collecting dust at those companie's, but their is no one around today that has the technical ability to revive the technique and skill to make those tubes. A lost Art. The tubes from that time would last for ten years or more, as compared to tubes today that are good for 4K to 6K hours. Another fact is at the time, speakers had a lower sensitivity of 83 to 86 db's. Speaker's today with sensitivity between 90 and 96 db's, have a more aggressive open top end. Speakers with much lower sensitivity have a more relaxed character. Back then most amplification in homes was between 25 to 40 watts. Also, tweeters back then were more simple and basic, and it wasn't until the late seventie's when Phase Technology in Florida invented and built the worlds first ferrous oxide fluid filled tweeter which improved the dynamic range. For the most part, it was the tube designs from fifty years ago that gave us that warm, rich, full velvety sound. If those type of tubes
came back on the market, we would return to the full analog glory that has been lost.