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

02-06-11: Stanwal
I would add that I find soft dome tweeters "warmer" [whatever that means] than metal domes...The metal domes seem wonderfully detailed and accurate but somewhat "cold".

I agree with this impression, Stan. Before hearing the beryllium tweeter in the Focals, I had never heard a metal dome tweeter that appealed to me, including those used in top notch speakers like Wilson. To my ears, the beryllium tweeter doesn’t sound inherently "cold" (though I have heard it give that impression when paired with certain upstream components). Having said that, it doesn’t sound inherently “warm” either. So while I suspect that, for this issue, the tweeter isn't hurting, I agree with you that it probably isn't helping either.

02-06-11: Almarg
The one thing that occurs to me that has not yet been mentioned, and which I think factors into "warmth" significantly, is hall ambience, or the lack thereof.

This had not occurred to me, Al. I suppose part of the reason is that, when I think of “warmth,” I tend to think of a sound that is “intimate” or “immediate.” In other words, I think of a high ratio of direct to indirect sound, which would typically correspond to listening to a live event from a relatively close position. But that may be an idiosyncratic association on my part. Like you, Hifibri seems to have the OPPOSITE association:

02-05-11: Hifibri
To complicate things in absolute terms, the FURTHER you are from the source of live music, the 'warmer' the sound will be perceived. [emphasis added]

This makes me wonder whether you, or Hifibri, would say that studio recordings (i.e. those with few or no ambient cues) can’t sound warm?

I should mention that I don’t think anybody owns the term “warm,” so I’m not disputing the “proper” use of the word. I would also add that it’s perfectly normal that folks have different associations with the term, especially in light of the fact that, in this context, it is highly metaphorical. Nevertheless, it's useful for me to hear other people’s understanding of it, because that may provide clues to what’s missing in my own system.

Bryon

Following up on my previous post...

02-06-11: Almarg
I certainly do not think that replacing your XA-30.5 with a tube amp would be the right approach. I say that partly because of the Pass amp’s outstanding reputation, but also because, assuming that the impedance characteristics of your 1027be’s are similar to those of the 1037be, the higher output impedance of a tube amp would result in increased treble emphasis and de-emphasized lower mids and bass, counter to what you are trying to achieve.

I had the same thoughts, Al. If my speakers were a little more friendly to tube amps, then I would seriously consider replacing the Pass amp (even though I like it quite a bit). So, if I want to add a tube amp to the system, then I would need to consider replacing my speakers as well. I don't have any great objection to changing my speakers either, except for the cost associated with it. Like all crazy audiophiles, the only other speakers I think about are considerably more expensive than what I currently own. :-(

If possible, I would like to explore ways of adding warmth to the system that don't involve such large (and expensive) changes.

Bryon

the output impedance of an amp has to do with the damping factor. it has no relation to treble response.

i own a tube amp and there is no peak in the treble or dip in the midbass or lower midrange.

consider the cj mv 125. that amp would hardly be considered bright or lean. yet when compared with ss amps its damping factor is much lower.

The output impedance of an amp has to do with the damping factor.

True. Damping factor is usually defined as output impedance divided into 8 ohms.

It has no relation to treble response.

Not true, in the case where speaker impedance is significantly different in the treble region than at lower frequencies.

If you look at the impedance curve that I linked to for the Focal Electra 1037Be, which I am assuming is similar to the impedance curve for Bryon's 1027Be, you will see that it is around 5 ohms in the bass and lower mid-range, and generally upwards of 10 ohms in the upper mid-range and treble region. That kind of impedance characteristic is not uncommon, btw.

For a given input voltage, an amp having negligibly small output impedance, such as most solid state amps, will maintain an essentially constant output voltage into that impedance as a function of frequency. Based on Ohm's Law, that will result in twice the amount of current and power being supplied into 5 ohms compared to what would be supplied into 10 ohms.

A tube amp, having relatively high output impedance, will not behave that way. The voltage that it "tries" to output will divide up between the speaker impedance and its own output impedance, in proportion to the ratio of those impedances. Therefore for a given input voltage to the amplifier, the amount of power that is delivered to the speaker at low frequencies will be smaller in relation to the amount that is delivered at high frequencies, compared to what a solid state amp would deliver. That will result in an over-emphasized treble.

If I recall correctly you have electrostatic speakers, which would interact with amplifier output impedance in exactly the opposite manner. The impedance of electrostatics decreases at high frequencies, so a tube amp would provide a treble response that is under-emphasized relative to what the response would be with a solid state amp.

Best regards,
-- Al

... When I think of “warmth,” I tend to think of a sound that is “intimate” or “immediate.” In other words, I think of a high ratio of direct to indirect sound, which would typically correspond to listening to a live event from a relatively close position. But that may be an idiosyncratic association on my part. Like you, Hifibri seems to have the OPPOSITE association.... This makes me wonder whether you, or Hifibri, would say that studio recordings (i.e. those with few or no ambient cues) can’t sound warm?

Others can undoubtedly speak to that more knowledgeably than I can, in part because most of my listening is to classical music that has been recorded in halls. But I would say that depending on the instrument, and on what is being played and how it is being played, warmth can in many cases certainly be captured and reproduced via up close miking in a studio. While at the same time it can often be better captured in a hall via more distant miking.

The key to that apparent paradox, it seems to me, is that warmth is a multi-faceted concept, as this thread makes clear. “Woodiness,” “body,” etc. are for example certainly important aspects of warmth, and their successful reproduction involves capturing the fine detail and harmonic balance of the instrument. That in turn can be expected to be compromised as distance increases. On the other hand, massed strings, to cite another example, can sound overly bright at close distances. As was noted above, high frequencies will be attenuated more rapidly as a function of increasing distance than low and mid frequencies. Also, reflected energy will be subject to frequency response contouring as a result of both the greater distance it travels before reaching the listener or the mic’s, and the acoustic properties of the reflecting surface. Finally, and perhaps most significantly, summation of reflected energy with directly captured sound will result in comb filtering effects.

So it would seem that optimal reproduction of recordings that are produced in a concert hall, at least, would involve drawing a balance between preservation of detail and harmonic balance on the one hand, and either reproducing hall ambience and distance effects correctly, if present in the recording, or enhancing them, if they are not present but should be. There would seem to be no easy answers ....

Best regards,
-- Al