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
"Warmth" is a very difficult characteristic to describe with adjectives. It's for me, the way real instruments sound in an acoustically neutral environment. Right now I'm listening to Strunz and Farah. They are both master acoustic guitarists. I have friends who play. The pluck of each string is there but so is the "woodiness" that the guitar body imparts onto the sound of each note as it is heard. A "lack of warmth" for me would be if the pluck of each string was unnaturally exagerated by a "hot" tweeter and the mid and lower mids were not able to deliver the woodiness of the instruments.

It can be a daunting task to get a system to this point, but is it ever worth the effort! Once you "tune" your system to achieve the inherent warmth of real instruments, the willing suspension of disbelief, can, with the right music, help create the illusion that you are indeed hearing the real thing. That would be the holy grail for me!
I think most can agree that reproduced music has warmth when violins dont sound like slaughtering poultry and piano transients dont sound like someone hitting your temple with a punching tool:

So how do I pick a pc of gear of mod a pc of gear to make it more warm?

To quote some ideas from Scott Frankland:
Warmth usually comes with
* regulated power supplies
* non inductive resistors (carbon composite)
* low odd ordered harmonics

and I would like to add to that:
* oil filled caps, be it coupling or bypass
usually they come with a more linear top end response to dynamics and a richer midrange (2nd order harmonics?)
* correct coupling cap orientation
* triode power tube config (to me Ultralinear never sound warm cos its actually anything but linear at least to my ears)
* use of chokes in power supply filter (that minimizes the unwanted spiky transient distortions from complex passages)

* Ribbon tweeters are normally NOT warm.

Warmth also comes with coherence. A poorly designed crossover will not give you the bloom and palpability of instruments that reaches out to you without attacking you when playing a wide range of pitches.

My 2 cents worth.
I have no idea how you 'make' warmth, but to me it sounds full bodied, textural, with a slightly plump bottom end, strings have bite, the top end is airy and delicate, without any hint of harshness. Too many components today are the opposite - strident, lean, clinical.

I guess aside from good guts, it's in the tuning by the designer.
Just a personal experience. I was at a high end salon sitting in a chair while they were setting up a system. They substituted various components and I could tell the difference as they did. The $2k cd player (Arcam) sounded fine but replacing it with a $3500(Linn) added a 3rd dimension to the soundstage. The speakers were the ones with the Be tweeter. The preamp was a tubed Audio Note 1 ($1k). Then they substituted a Linn ($1500) solid state preamp. The sound became shrill and I was pretty much driven out of the store. It wasn't even close. So warmth to me was tubes that made me want to listen indefinitely. I think they did that on purpose when they figured out I wasn't buying that evening. :)
Hi Bryon - for me, assembling a system that sounds "real" is automatically also going to be a system that sounds "warm." I suspect this is true for the great majority of audiophiles out there, especially those whose reference is live, unamplified acoustic music in a good performing venue (I am assuming, for instance, that this is what HIfiman means by "acoustically neutral," but I could be wrong). A good performing venue is "warm." I have never heard a system I would describe as "cold" or "harsh" that I could also describe as "real." Hifiman also speaks of the "inherent warmth of real instruments", which is certainly true, and I would also add the human voice to that. Though an actor may make his voice sound as cold as possible, there are extremely few instances where a singer would do so. Even HIP groups that don't use vibrato still have a natural warmth to their string tone. I really don't care how well a high-end system may measure, if it doesn't sound real/warm, and IMO/E, way too much high end equipment falls short. As for technical reasons why, I am certainly nowhere near as qualified as many others on this board to answer that; but this does put me in mind of something I read I think last night in a different thread where Atmasphere said, and I am probably badly paraphrasing here, that designers often have a choice between making equipment that measures well, and equipment that obeys the rules of human hearing. Perhaps he will weigh in on this thread.

Incidentally, part of the above is another instance of confusion that results from the use of the term "neutral." :)
Play "Light My Fire" over and over again.
I agree with Hifiman. Your system has to have enough 'warmth' inorder to portray music naturally and realistically. I think it's a matter of degrees: too little warmth and the result will be overly sterile and analytical, too much warmth and you get a syrupy sound (which I define as slow with an emphasis in the upper bass/lower midrange). I think of it as a continuum:

analytical___________________________syrupywarm

The trick is to first determine generally where on this continuum your taste lies and then,secondly, to assemble your system components to match your tastes. Easier said then done, for sure. I would say most A'gon members' tastes lie between somewhere, where the warmth is, with very few at the extremes.
Looking back on my system evolution, I clearly moved from an original analytical system to a current system that is much warmer without consciously thinking in these terms. But I can remember that I was looking for more realism and that illusion of 'you are there'. I know now that I was wanting more 'warmth',depth and presemce.
But your question was about how do you get more warmth. There was another recent thread about 'bloom' that you may want to read. I think the 2 concepts are closely related. In my limited experience, I would suggest tubed equipment needs to exist somewhere in your audio chain (source, preamp,amp) to obtain good, natural warmth and bloom. I don't deny you can achieve some warmth and bloom with solid state equipment but you'll need to select carefully and have deep pockets to be successful. Speaking of which, your system is very nice and I don't see any obvious cause of a lack of warmth. I don't think your Focal spkrs or Pass amp are responsible. I am definitely no expert but that won't stop me from making one suggestion: experiment. You could try out a few tubed preamps to see if this gives you the desired warmth(hopefully, there are some local dealers that will accomodate this). This worked for me. I'm not familiar with your preamp/processor or the mods but know you've made a big investment in it. But even if you substituted a different preamp, you could still utilize your current preamp as a prossessor if the new preamp has a HT passthru. Not sure if I helped but wish you good luck on your search.

According to Technical Director of Benchmark John Siau, DAC1 that I own, was specifically designed not to sound warm but rather natural without enhancement of any harmonics odd or even. Enhancing even harmonics does sound really nice with guitar or voice but not so with instruments that poses a little more complex than regular overtones harmonic structure. Piano is such instrument (as well as percussion instruments) and when it is reproduced on very warm equipment it sounds almost like out of tune.

On the other hand SS gear often designed to sound hi-fiish or for good spects on paper enhances (because of transient intermodulation introduced by deep negative feedback) odd harmonics. Our ears are very sensitive to odd harmonics since loudness cues reside there (like 7th or 9th harmonic).

Neutral sound (whatever it is) is the best but I understand that staying a little on warm side protects from brightly recorded material. Fortunately my Hyperion speakers sound slightly warm with zero sibilants on any CD - and it is in combination with Benchmark DAC1 and unforgiving class D amp.
My older speaker had aluminum dome tweeter and was unbearably bright in the same setup.
Your post should have read , " Warmth why would you want it ". Warmth is an added artifact of electronically produced music . A properly tuned acoustical instrument should not have the added warmth that you here on many systems . Having tuned musical instruments in the past , one thing we listened for was any unnatural warmth , if you could hear warmth something was wrong . Warmth was never considered natural or desirable . It would altar pace, pitch, flow and timing and make an instrument sound less neutral , most easily noticeable on sting instruments . Have A musical day
Having an always "warm" system is like a preference, choice , or flavor and may not be for everyone. I have a small body acoustic guitar and if played back through my system I wouldn't want or expect it to sound warm. I also have a big bodied mellow and bassy sounding guitar and wouldn't want that one to sound thin or bright. I can choose which guitar to play for different sound but I want my system to be neutral and have the capability of being true to the source. That's my preference.
I am currently using a Dynaco ST-70 amp unmodified and a Hafler DH-110 solid state preamp and it gives me plenty of warmth. Instruments and voices sound natural not strained and I found I preferred this sound to the all solid state sound setup I had before. My vintage Mcintosh ma-5100 also gives me the warmth Im looking for even though it is all solid state. So experiment with vintage tube and modern tube equipment to find the sound u r looking for. Thats the fun in hifi is the experimentation and trying something new and different sounding.
'Warmth' for me is created by a tonal balance that makes reproduced large-orchestra music sound like real music played in a good hall. Of course, a 'good' hall is one that supports the lower frequencies of the orchestra so that the music doesn't sound 'cool' or 'thin'. 'Rich' is another word for warmth. I think the recording processes remove warmth from the music, and a music-reproduction system must recreate it. Warmth is defined, for me, as a tonal balance with a dB or 3 more energy in the lower MR/upper bass...mayb eup a dB by 300Hz, rising to maybe 3dB by 100Hz and maintaining that thru the bottom octave.

Of course, one can go too far on the warmth scale, which turns to 'thick', and that too doesn't sound real to me.

Systems that measure flat tonally are too thin and too bright for me.

Vacuumtubes in the system help retain natural musical warmth, but IMO the speaker system is most responsible for a system sounding warm and real...or not.
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here is a definition of warmth:

a slighy peak in the upper bass/lower midrange in conjunction with a dip in the upper frequencies, usually starting at about 3k.

it is definitely a coloration.

there is a difference between accuracy of timbre and warmth.

when attending live unamplified music, one usually does not use the term warm to describe a musical experience.

what distinguishes live music from listening to a stereo is accuracy of timbre .

an instrument soundws real when you hear it, but not real, maybe almpst real when you hear it on a recording.

very often "warm" is synonym for tube coloration of a euphonic nature.

it is an audiophile term which is not part of the definition of music.
Well said Mr. T...Many like the warm coloration of tubes , but it was one of the reasons I got ride of my tubes .
I must say though , I have friends with excellent all tube setups , and enjoy listening to them very much
Regards Tim
Thanks to everyone for your thoughtful responses.

02-04-11: Hifiman5
"Warmth" is a very difficult characteristic to describe with adjectives. It's for me, the way real instruments sound in an acoustically neutral environment...A "lack of warmth" for me would be if the pluck of each string was unnaturally exaggerated by a "hot" tweeter and the mid and lower mids were not able to deliver the woodiness of the instruments.

Hifiman - On good recordings, my system sounds warm, according to the standard you describe. In fact, I would say the most realistic sounding instrument on my system is acoustic guitar. You may be asking, ‘So what is the problem?’ There isn’t a problem, exactly. On well recorded material, everything is peachy. But on poorly recorded material, I wonder if a “warmer” sounding system would be more rewarding. So, my goal is to expand the range of recordings that sound excellent on the system.

Johnsonwu - You've given me a lot to think about and to research, since I'm not a modder (though I have had some gear professionally modded). This approach to adding warmth is one that interests me. Maybe it’s because changing internal components (caps, resistors, etc.) is as close as it gets to single variable changes, which is appealing to me for its conservatism and degree of control.

Hi Learsfool – I agree with you and with Hifiman that, for acoustical instruments, warmth is a necessary condition for the perception of “real.” Again, on good recordings, acoustic instruments do sound warm, and hence real (to my ears). It’s the poor or merely adequate recordings that I would like to enhance, if possible.

Noble100 - I am considering adding tubes somewhere. Probably not a tube preamp, because I have recently been swayed toward the school of thought that the best preamp is no preamp (i.e. source connected directly to amp; volume controlled, in my case, by computer software). That leaves a tube amp or a dac with a tube output stage. That choice raises some questions:

For the issue of adding warmth, does it matter where in the system the tubes are located? Is the common element of “warmth” in tube components simply the addition of low order harmonics to the signal? And what are the downsides of this approach to adding warmth?

The last question brings me to...

02-05-11: Kijanki
Enhancing even harmonics does sound really nice with guitar or voice but not so with instruments that poses a little more complex than regular overtones harmonic structure...NEUTRAL sound (whatever it is) is the best…
02-05-11: Tmsorosk
Having tuned musical instruments in the past, one thing we listened for was any unnatural warmth, if you could hear warmth something was wrong. Warmth was never considered natural or desirable. It would altar pace, pitch, flow and timing and make an instrument sound less NEUTRAL, most easily noticeable on sting instruments.
02-05-11: Bizango1
I want my system to be NEUTRAL and have the capability of being true to the source. That's my preference.
[emphasis added]

You folks sound like me in another thread, where I argued at great length, against great opposition, for the value of neutrality. Some may find it amusing that I am now asking how to make my system warmer. I haven’t really changed my mind about the whole subject of neutrality. On the whole, I still believe that it is one of the most valuable attributes in a system, for the reasons I expressed on that thread. But I am interested in experimenting with changes that might nudge my system just a bit in the direction of greater warmth. Whether or not that is a nudge AWAY FROM NEUTRALITY is a philosophical question around which we should probably tread lightly, lest this thread turn into Neutrality War II.

The real question I am hoping to explore is HOW you go about making a system warmer. That is, what characteristics of system design promote the impression of warmth, and what are the drawbacks of those characteristics, if any? Part of answering this question involves answering:

Is greater warmth in a system always achieved by ADDING something (e.g., low order harmonics)? Or is it possible that greater warmth can also be achieved by SUBTRACTING something (e.g., some kinds of distortion)?

Thanks again to all.

Bryon
While most agree on the basic meaning, destinctions need to be made about the 'degree' of warmth (pun intended). I think a lot of confusion arises in the inference of the amount of warmth being described and because audiophiles do not have an exact universal definitin. As has been said, it's like trying to describe the smell of an onion or any smell. In general, live music can be described as being warm, as in alive and rich with tone. On the other hand one can describe a system as being 'warm' meaning it is too warm and not natural sounding. The more one listens to various types of live unamplified music, the more one appreciates 'warmth' (rich tone) as being closer to the truth. High frequencies and detail decay faster as distance from the source increase (including many of the attributes the OP indicates). A lot of music is closed miked which captures more high frequency energy and detail
(depening on the recording engineer and mastering of the recording), than a listener in that venue might otherwise hear, making a 'warm' system sound more real with many recordings. The more one listens to different types of live music, with different types of instruments, in different spaces, the more one realizes 'the sound' is always different, yet there is usually always that warmth of tone. Since this is a universal quality of live music, it makes sense to strive for this quality in a system. As always, it's a matter of one's perspective and is just one more aspect that makes this hobby so much fun!
IMO Hifibri's got it..."The more one listens to different types of live music, with different types of instruments, in different spaces, the more one realizes 'the sound' is always different, yet there is usually always that warmth of tone. Since this is a universal quality of live music, it makes sense to strive for this quality in a system."...
...and Mrtennis doesn't. As I said and Hifibri reinforces, the recording process removes natural, real warmth of tone from the sound of the instruments, and it's the reproduction system's job to recreate it. Indeed the system that do that are NOT tonally nuetral or 'accurate', but to me 'accurate' systems sound so much NOT like real music that they're unlistenable, so how accurate is that?

Tuning a system to have the right amount of warmth without sounding thick is difficult, but creating a great-sounding system is tough, isn't it?!?!?!
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...jeez, Jeffrey, spell much? Sorry, hit the wrong button.
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I do not find most systems that I would describe as "warm sounding" to be natural sounding.

Pleasant, especially with acoustic string instruments, yes, but not like what I hear live.

Electronic music often suffers on a too warm sounding system.

GEtting the right dash of warmth perhaps when needed and still sounding good overall is tricky business indeed. Trail and error is the best approach.

I would recommend targeting a neutral sounding system first. Then tweak a pre-amp or source with some tube gear perhaps to get the dash of warmth if needed.

I find the ARC pre-amp in my rig does this perfectly for me. I notice that dash of warmth on occasion but only with certain music and if I am really listening just for that specifically.
Byroncunningham,

After looking at your excellent system, I'd like you to consider one inexpensive addition that may tune just a bit more smoothness and warmth into your system without a loss of dynamics or bass slam.

I have been working for a very long time at "tuning" my system to get just the right sense of warmth so the music sounds as "real" as possible.

Using the correct footers under my components was the final tweak that took my system where I needed it to go. I would be embarrassed to admit how many different types of footers I have tried (some quite costly) that are now either being used in our videos systems or are in exile in my closet.

So what worked? Herbie's Tenderfeet from Steve Herbelin. I am using a combination of the regular version for lighter components and the extra firm Tenderfeet under my power amp.

I couldn't tell from your photos if you have footers under the Meridian and Pass pieces but I would most strongly urge you to try the appropriate Tenderfeet and give them a listen. Steve always stands behind his products. If you don't like the outcome you'll just be out some shipping.

After reading this entire thread, especially your last posting, its sounds to me like you are just close enough that the Tenderfeet could get you where you want to be.
Jeff,
I don't think Mrtennis is wrong, the definition he gives for warmth is correct, the point is it's a matter of usage and of degrees. His definition describes a sound that is too syrupy, rather than using it to describe the 'truth of timbre' he used to describe live music. Some might call the truth of timbre of live music 'warmth' (rich body) as you and I do, others may call it neutral and only use the term 'warmth' to describe a sound that is not neutral. That's the difficulty we face in describing sound that can create long threads of angst. To complicate things in absolute terms, the further you are from the source of live music, the 'warmer' the sound will be perceived. One must decide what listening position in the hall are you trying to re-create with your system. Some like mid hall, others like the perspective of the microphones hanging above the performers. There are lots of factors to consider. Building a system that gives you the smallest compromises on the factors you value most is not "tough", its what makes this hobby fun!
"One must decide what listening position in the hall are you trying to re-create with your system"

That's a very good point that I suspect is often neglected.

THings sound a lot different depending on where you listen from. Getting this right and to your taste is a very valuable and free tweak.
And it would depend who and what is playing for me to no wear I would want to sit in the hall .
Hi Tmsorosk, may I ask if you are referring to acoustical "unplugged" music or electronically produced music as perhaps in a rock concert?

I go to classical concerts and recitals often (actually almost every week these past couple months) and I find that no matter where I sit, the concert hall sound is "warmer" than most stereo systems I hear (absolutely not at the dealers), including mine.

I can never hear that "Krell" and "Audio Research" kind of crystalline clinical sound when playing classical music
when I attend a live classical concert. I think that's their coloration to make it sound "wide open and airy" to attract a prospective customer has only 10 minutes or so at a stereo shop.

BTW in my opinion not all tube amps color its sound reproduction with warmth, and not all SS amps are cold and sterile (Pass XA....5 series and Paul Weitzel's TRL amps are solid state but they are warm sounding and I am sure many can agree with me)
Hello Johnsonwu... Most of the venue's we attend are JAZZ , not amplified . There has been times when we were so close that the horns would drive me back after a few songs , ya standing in the back . I'm not sure how loud the horn's were at that distance , I'dd guess over 100db , my ears rang for hours after . So now when I hear that we are going to a concert , I find out the particular's before picking out seat ticket's .
The liquid coherent sound that live music portrays I would not refer to as warm .
Whether it's tube or solid state the interpolation of warmth that equipment designers add to give a component realism can hardly be compared to what we hear live . Happy listening , live or recorded . Tim
Hi Bryon,

Another of your fascinating and thought-provoking threads, which expectably has stimulated some excellent responses.

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.

It seems to me that proper reproduction of hall ambience is a key factor underlying Learsfool's astute comment that
Assembling a system that sounds "real" is automatically also going to be a system that sounds "warm." I suspect this is true for the great majority of audiophiles out there, especially those whose reference is live, unamplified acoustic music in a good performing venue.
And it strikes me as a key factor in achieving the "richness" that several other posters referred to.

Hall ambience, of course, was discussed at great length in your excellent "They are here" vs. "You are there" thread. Obviously its proper reproduction is highly dependent on the recording. I would offer the hypothesis that recordings that are lacking in "warmth," or "richness," or which tend not to sound "real," commonly have not adequately captured hall ambience.

If so, the obvious question is what to do about it. One approach, which iirc you offered in the other thread, is to try to adjust room acoustics such that they draw a reasonable compromise between adding some semblance of concert-hall acoustics to enhance the presentation of ambience in the case of mediocre or poor recordings, while not overshadowing the ambience that is captured on good recordings. Obviously there will usually be practical limitations to how effectively that can be done.

Another approach would be to try to adjust frequency response. But while emphasizing upper bass and lower mid-range frequencies, for instance, may to some rough approximation replicate the frequency response effects of hall ambience, that approach will be unsatisfactory IMO because it does not address the timing relationships between direct and reflected sound.

What does strike me as likely to be, in general, the most promising way of enhancing warmth and ambience on mediocre and poor recordings, without significantly compromising the reproduction of well done recordings, is the introduction of tubes into the system, as others have suggested above. The added dimensionality that is commonly attributed to tubes (that attribution being correct in my experience, although from a technical standpoint I have no idea why that would be so), and perhaps the relative emphasis that they may give to lower order even harmonics, seem to me to be the best way of achieving that balance.

Concerning where to put the tubes in the system, as you’ve no doubt seen there have been many debates on that question in prior threads here, with opinions sharply divided. FWIW, I am in the tube power amp camp. However in this case 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.

So I have no bottom line answer to suggest, beyond some of the suggestions that have already been made, but those are some thoughts.

Best regards,
-- Al
Recognizing that the term "warmer" appears to be impossible to define with any degree of consensus I would add that I find soft dome tweeters "warmer" [whatever that means] than metal domes. I base this on the Scanspeak ones in my Spendor SP 1/2Es and S 100s and Gamut L5s and the Focal Titanium ones in the Mini Utopias I use to have and in my friends Wilson's. The metal domes seem wonderfully detailed and accurate but somewhat "cold". Others would doubtless have other reactions and I am sure there are differences in their behavior that are not reveled in simple frequency response tests.
when i defined warm i did not quantify the peaks or dips in the treble and bass regions, respectively.

syrupy or dark might be the result of a large deflection from neutrality (what is large).

my favorite spot in the concert hall is the last row orchestra, there is some loss in reolution and a roll off in the treble, although i am not sure where it starts.

considering the distance from the stage to my seat, other things may be happening as well.

but again, warmth and live are not the same.
one more consideration:

warmth is a spectral balance. it is different from neutrality. it must concern the realtionship or balance between the treble and bass regions.

thus as far as arecording is concerned, it is tuning of a stereo system to create a particular balance that provides a greater emphasis upon the bass region than the treble region.

it probably results in a loss of resolution.
FWIW, and its already been discussed fairly well, I think the terms warm(er), neutral, or cool/analytical, are difficult when used to discuss the sound of music. Audio, OK, maybe.

Not to be overly simplistic, but what turns me on is always a sound that is natural, sympathetic to the sound of live music, and draws my attention to musical content and detail, but not so much the stereo/multichannel effects created by a well executed system.

For the most part I listen to live music in the orchestra section row G dead center where the power of the orchestra, the separation of instrumental detail but where the total integration of the orchestra is best (for me). The sounds from the string sections, violins especially, are never dominant nor screechy (bright, too prominent, which is often a product of the recording itself) and small groups and solo instruments in a recital hall (which has superb acoustics.) So I have selected components, speakers, etc, which replicate best that live experience. BUT IT'S NOT LIVE and that is not my audio goal.

FWIW I really agree with most of hifiman5's comments.
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
02-06-11: Almarg
“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.

This is a good point, Al, and it makes perfect sense of the idea that, in at least some cases, warmth increases as the distance of the listener to the live event increases. That would explain the correlation you observed between recordings with ambient cues and those with warmth. On the other hand, it also seems to suggest that, for smaller scale performances, warmth might DECREASE as the distance of the listener to the live event increases. So maybe there is reason to believe that a common characteristic of warm recordings is that the distance of the microphone to the live event is “proportional” to the scale of the event being recorded. That idea makes a lot of sense to me.

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.

The first of these points is more or less what I meant in the OP by item #5, which I called “room resonance,” but would probably more accurately be called simply “room acoustics.” Having said that, it never occurred to me that comb filtering might be a detriment to a system’s warmth. That strikes me as a plausible idea, since the destructive interference of comb filtering effects could conceivably result in a kind of "harmonic thinning,” which might very well be experienced as a lack of warmth. An insightful observation, Al.

Bryon
Once again, more proof of the need for a better audiophile vocabulary; one which, if it is to have any real meaning, needs concensus. A good place to start is, ironically, outside the audiophile world; in real world vocabulary. How often do we say something like :"Joe Toob is a warm person", or "John Fett is not a very warm person, he is cold". When we say these things, are we referring to anything having to do do with frequency response? Probably not. We are probably referring to wether a person is amiable or not. I think the term warm, in the audio context, is being misused, and has more to do with a components ability to draw you in, and let you get involved with the music. Frequency response certainly plays a role, but I think more impotant in determinng a component's "amiability" is the texture of the sound it makes. This can be independent of perceived brightness, or darkness. I have heard components that sound way too dark, and thick through the midrange, but are also very dry sounding. Conversely, I have heard some that I would consider way too bright sounding, but are also very liquid sounding. Texture. Micro dynamics ability is the other key factor. That is where a component's ability to convey a performer's expressive qualities lies; the warmth of the performance.

Music that approaches the sound of a live performance is, by defintion, warm. The sound of live music runs the gamut as far as wether it sounds shrill, bright, dark, etc. It is the human element that makes it warm, or not. What gives music that hard to describe texture, and dimensionality is the human body attached to it.
Consensus in audio ???
You're right. What was I thinking?!?
hi almrag:

so, you are saying that a tube amp would have a ddifferent freequency response than a ss amp, when driving an electrostatic speaker.

would you expect the difference to be as much as 5 db difference at frequencies exceeding 3 db, or what difference in spl would you expect and at what frequencies ?

how might the frequency response change if the amp was a hybrid (tube input stage), such as the aria amp, designed by mike elliot ?

i have quad esls and am considering the aria wt 100. it has a tube front end and bi polar transistors.
Hi Bryon and Al - Al, you interpreted my comments exactly right, and clarified/elaborated them nicely with your discussion of hall ambience. Bryon, I am not so sure, though, that it has as much to do with distance from the performers in the hall, other than to state that to be too close is not ideal, as the sound will definitely be brighter. And sound does generally travel up and back in a good hall, so that the "nosebleed" seats in many halls are actually the best ones. However, the latter is not always true, often mezzanine seats, or seats in the middle to the back of the floor are best (as long as they are not under an overhang, then they are definitely the worst).

As to the question of whether or not something recorded in a studio can be "warm," that is a much more interesting issue. The studio itself is of course a very cold, dead space. I would say that the vast majority of the time, studio recordings that sound "warm" have been altered with digital reverb, etc. - studios are the playgrounds of the engineer, for sure. And while Al may be right that close miking can result in some good studio recordings of certain instruments, this is IME not usually the case - normally close-miked recordings of acoustic instruments do not sound very good, if by good we mean "real." This, to me, is sort of equivalent of sitting too close in a concert hall. I guarantee you that whenever an engineer puts a mike too close to an instrument, the player tries to move it as far away as he can get away with.
Mrtennis 02-07-11: So, you are saying that a tube amp would have a different frequency response than a ss amp, when driving an electrostatic speaker.
Yes. The ss amp will produce a brighter and more extended top end than the tube amp with an electrostatic (which may or may not be preferable, depending on the particular components, the room, the listener, etc). The same ss amp will produce a weaker and less extended top end than the same tube amp, when used with dynamic speakers having an impedance curve similar to Bryon's Focals.

In other words, one amp can be either more bright or less bright than another amp, depending on the speaker that is being used!
Would you expect the difference to be as much as 5 db difference at frequencies exceeding 3 db, or what difference in spl would you expect and at what frequencies
It depends on the damping factor/output impedance of the tube amp, and the impedance curve of the speaker. I did a quick calculation based on the impedance characteristic of the original Quad ESL, and based on a 2 ohm output impedance (damping factor 4) for the tube amp, and a 0 ohm output impedance for the ss amp. The ss amp in that case would be about 6db stronger in the 15 to 20kHz area than the tube amp. The 6db number would be smaller if the damping factor of the tube amp were higher.
How might the frequency response change if the amp was a hybrid (tube input stage), such as the aria amp, designed by mike elliot? I have quad esls and am considering the aria wt 100. It has a tube front end and bipolar transistors.
With respect to the effect we are discussing, that amp would behave the same as a purely ss amp. What counts is the type of output stage, which is ss in this case. Consistent with that, the amp has a damping factor of 44 according to the specs shown in this review.

An important consideration with many electrostatics, also, is that the amp not be weak in terms of its current capability, because current requirements will be increased as a result of the capacitive nature of the speaker's impedance. The WT100 certainly appears to meet that requirement, based on the specs and description shown in the review linked to above.

Learsfool -- just saw your comments. Thanks! Your perspectives on these kinds of questions are always particularly valuable.

Best regards,
-- Al
02-05-11: Tmsorosk
Warmth is an added artifact of electronically produced music. A properly tuned acoustical instrument should not have the added warmth that you hear on many systems.
02-07-11: Frogman
Music that approaches the sound of a live performance is, by definition, warm.

It’s interesting that some folks experience live acoustical music as "warm," while others do not. Maybe that’s a consequence of how people hear differently. On the other hand...

I suspect that it’s a consequence of how people understand the conceptual metaphor of 'warmth.' Many metaphors have a systematic structure and consistent rules of use. But this thread seems to highlight that, for the metaphor of 'warmth' in audio, there doesn’t seem to be a systematic structure or consistent rules of use. It's no wonder, then, that consensus on the issue of warmth is difficult to achieve, since there is reason to believe that, much of the time, people aren't even talking about the same characteristic.

Bryon
Get a heating pad!!
Bryon, exactly. It’s like using the word ‘blue’ to describe a color. It only gets you in the ball park unless you describe the hue, intensity (value), contrast, gradation etc. in known terms. In my experiences warmth is relative and is dependent on context. To complicate things, as system accuracy improves and smaller differences become larger, not everyone describes these differences in the same absolute terms. A neutral system compared to a sterile system will sound warm(er) and can be described that way as more natural, neutral etc. A system can be neutral but as a requirement must have warmth. Because accurate tone can be difficult to describe, the word warmth is helpful in describing the accuracy of that tone. "The sax was warm and round sounding, as if it were in the room." could be an acceptable statment. Of course the term can also be used to describe a system that is too warm.

Ambient information, or ‘air’, which is key in recreating the recording space is not necessarily the same as warmth. A sterile system can and frequently does have lots of ambient information, but lacks body or warmth.

Recording studios can and usually are 'warm', dead maybe, designed to lack reverberations to control the sound, but not usually characterized as cold. Great pains are taken to control studio acoustics.

All instruments, some more than others have a degree of directionality, so your listening position in relationship to them (distance and direction) will affect the sound perceived. The same is true for microphones. Close miked sources can have more high frequency energy than you would hear from a normal listening position. In addition, the proximity effect of microphones increases bass response of the signal the closer you place a mike to a source like a guitar or vocalist. A lot of singers like this effect as it adds richness to their voices. When you hear a studio singer, you are usually hearing it from the perspective of the singers mouth on your nose (where the mike would be), being played through speakers in front of you. Hardly a 'natural' situation. Instruments, room acoustics, microphone and equipment selection and placement, multi tracking, all manner of tweaking and manipulating the sound after it is captured, and lots more must be accounted for in the recording process to create a recording to give what they hope you consider a natural sounding perspective. In general, its unrealistic to think a recording would ever be heard exactly that way live. Although it’s amazing it works as well as it does...well, sometimes anyway.
it would facilitate communication if there were "standard" definitions for terms frquently used in discussion so that each of us would not have to qualify or explain the denotation or connotation of terms used in a sentence.

there are many words that are so frequently used, such as warm, rich, lean, thin, bright, wide sound stage, deep sound stage, out of phase, and other familiary used words.

while systems are different, as our ears , brains ad preferences, terms could have a shared meaning so that in the context of a stereo system, the meaning would be clear.

how to do this ??

i suppose someone could propose a list of terms and their definitions and then those definitions could be discussed until there was an acceptances of a definition.

i think there are more experienced audiophiles than muyself who could propose a definition of the terms i alluded to above, but if asked, i would be willing to provide a definition.

i don't consider myself an authority and if someone wants to offer definitions i think such an undertaking would be greatly appreciated.

this is especially the case when some one asks for advice regarding an aspect of sound, such as "bright" and the posters would understand to a large extent, what was meant by the term.

this discussion of warmth illustartes the differences in connotation that each of us use when saying the word "warm".

i think precision and clarity would ad directness and eliminate the necessity for explantions.
Definitions will only get you in the ball park. Its about communicating effectively. This is the difference between a good equipment reviewer and a lesser one. Audiophile terms help, but the good reviewer gives you a better sense of the sound through better descriptions and context.
One thing I’ve noticed about the various characteristics that go by the term ‘warmth’ in the context of playback is that most or all of them seem like ADDITIONS to the signal. For example, ADDITIONAL low order harmonics, ADDITIONAL lower midrange/upper bass, ADDITIONAL ambience provided by the listening room, and so on.

Strictly speaking, any additions to the signal (other than gain) are deviations from accuracy. For that reason, I think many audiophiles, myself included, are tempted to eschew them. But lately I've been having second thoughts about that attitude. I’m starting to wonder about the relative merits of the following two characteristics:

1. Accuracy to the recording
2. Accuracy to the recorded event

The relative merits of accuracy-to-the-recording vs. accuracy-to-the-recorded event has periodically occurred to me ever since, on the neutrality thread, Al wrote this:

12-02-09: Almarg
A perfectly accurate system…would be one that resolves everything that is fed into it, and reproduces what it resolves with complete neutrality. Another way of saying that is perhaps that what is reproduced at the listener's ears corresponds precisely to what is fed into the system.

Which does not necessarily make that system optimal in terms of transparency. Since the source material will essentially always deviate to some degree and in some manner from being precisely accurate relative to the original event, then it can be expected that some deviation from accuracy in the system may in many cases be complementary to the inaccuracies of the recording (at least subjectively), resulting in a greater transparency into the music than a more precisely accurate system would provide.

Which does not mean that the goals of accuracy and transparency are necessarily inconsistent or in conflict. It simply means, as I see it, that the correlation between them, although substantial, is less than perfect.

Al makes his point about accuracy in terms of neutrality vs. transparency, in keeping with the nomenclature of that thread, but it is essentially the same distinction as accuracy-to-the-recording vs. accuracy-to-the-recorded-event, or Recording Accuracy vs. Event Accuracy, for short.

I agree with Al that Recording Accuracy correlates with Event Accuracy, but not perfectly so. In other words, I now believe that efforts to maximize Recording Accuracy sometimes come at the expense of Event Accuracy, which is a viewpoint that, I suspect, more experienced audiophiles tend to adopt, but has taken me some time to appreciate. A turning point for me was an observation that Albert Porter made in an old digital vs. analog thread, which I read only recently:

09-12-08: Albertporter
The digital (or analog) master tape is not the issue here, the CD format is.

If any of you could hear a master digital tape (or hard drive) and compare that to CD or LP, you would realize how much we've been screwed. The problem with digital is when that great master is "moved" for public distribution…

Moving that master digital signal from one place to another and from one sample rate to another does it so much harm it cannot be repaired. Then to make matters worse, our only choice is an outdated format that's too low a sample rate to replicate what was on the master…

With CD, you get a severely downsampled format that's only a shadow of what could be if the format had evolved this last 25 years.

This observation resonated with me, as I have had the experience of recording, editing, and mixing with high quality professional equipment, to create a master recording I was proud of. I then watched - dismayed - as my master recording was compressed, downrez'd, and finally, transferred to its delivery format. Even on a very high quality playback system, the delivery format's recording was a shadow of its former self. Albert Porter’s observations about CD recordings undergoing this process of diminishment as a matter of routine procedure highlights the many respects in which the recordings available to consumers deviate dramatically from their master recordings, to say nothing of how the master recordings themselves deviate from the recorded events. Taken together, both deviations create a gulf between the live event and its consumer playback, a gulf that some audiophiles try to fill with ADDITIVE measures. And that brings me back to the point of this post...

It now seems to me that the use of ADDITIVE measures can be a means of filling, to whatever extent possible, the gulf between the live event and the (in many cases) extremely diminished recordings available to consumers. IMO, that provides a plausible rationale for sacrificing a small measure of Recording Accuracy for the sake of potentially greater Event Accuracy. Put another way, it provides a rationale for the ADDITIVE approach to playback.

Just which types of additions are the right ones is another matter entirely.

Bryon
02-08-11: Mrtennis
it would facilitate communication if there were "standard" definitions for terms frquently used in discussion so that each of us would not have to qualify or explain the denotation or connotation of terms used in a sentence...

this is especially the case when some one asks for advice regarding an aspect of sound, such as "bright" and the posters would understand to a large extent, what was meant by the term.

I agree with you, Mrtennis, and I think you've identified another term that is often in need of clarification, namely 'bright.' Some people use it exclusively to refer to frequency response, but other people seem to use it more loosely to include anything they don't like about high frequencies, like shrillness, grain, glare, etch, etc..

Of course, all of these terms are imperfect descriptors of what is actually heard. But the subtle differences among them are often significant, as they can suggest different diagnoses of the problem, and therefore different remedies.

FWIW, what I find particularly valuable is any effort to correlate subjective terms like 'warm' or 'bright' with the objective characteristics to which those terms could refer, which was part of my motivation for beginning this thread. Correlating subjective descriptions with objective characteristics not only might help facilitate communication among audiophiles, but it might also contribute to our understanding of why some systems sound more like real music than others.

Bryon
I would like to comment on one thing that Hifibri said - while I agree with pretty much all of the rest of the post, I would disagree with this part: "Recording studios can and usually are 'warm', dead maybe, designed to lack reverberations to control the sound, but not usually characterized as cold. Great pains are taken to control studio acoustics. "

Great pains are usually taken indeed, but almost never to make it "warm." In fact, quite the opposite - the engineers want the room to be as dead as possible, as they want to totally control the sound not only of the room itself, but even more importantly (and objectionably, to us musicians), of the actual instruments/voices. This is true not only of small studios, but also of the big studios in Hollywood and London. Some very famous musicians truly detest what some engineers do to their sounds in the studio, including in the top movie studios.

By the way, this does not necessarily mean that the resulting sound is bad; but although it may have cool effects, and the recording itself made and edited and mixed very well, it usually has very little to do with what the musician actually sounded like (although for the vast majority of pop singers, for instance, this is actually a very good thing, and they love it).

Also, this is not to say that the studio cannot be made to sound more like a real performing venue - once I had the pleasure of playing with an orchestra I was in with Georg Solti in Abbey Road studios (it was a one-off rehearsal in a training orchestra), and most of the deadening treatments in the room were pretty much removed for the purpose. And this is sometimes done for big budget films where the score is an even more than usually important part of the film. But what I am saying is that this is never done for the overwhelming majority of studio recordings - if they wanted it to sound like a concert hall, they would record in one. Usually, the room sounds so cold and dead that it is actually hard to hear your fellow musicians - the sound dies almost as soon as it leaves the instrument. Of course, normally there is a click-track going on in earphones you are wearing anyway, so there is very little sense of ensemble in any case. And of course, it is usually a much smaller ensemble than a full orchestra, but that just gives the engineer that much more control over his production.

Bryon, some of this also relates to your Recording Accuracy/Event Accuracy thing. Obviously, I am almost always much more interested in the latter than the former, with the type of music I perform/listen to. But if one listens either entirely or at least primarily to electronically produced music, then all of the above is nowhere near as big of a deal (if not practically irrelevant!). It is certainly a hell of alot easier for engineers to manipulate the sounds of electronic instruments exactly how they want to.