Holographic imaging


Hi folks, is the so called holographic imaging with many tube amplifiers an artifact? With solid state one only hears "holographic imaging" if that is in the recording, but with many tube amps you can hear it all the time. So solid state fails in this department? Or are those tube amps not telling the truth?

Chris
dazzdax
In a buddy's listening room a set up consisting of Marten Design loudspeakers, Krell pre- and power amplifier (KSA 150) the sound was flat and not musical, while in the same listening room the sound through the Marten Design speakers with CAT preamplifier and Gruensch power amplifier was holographic, natural and dynamic. Which combination was the most "objective"/truthful? Should one disregard units that sound more holographic than most?

Chris
Chris,
This, to my mind, is an excellent question. But is there such a thing as too much holography? In a natural event, say a string quartet, which I listen to often live, and I drift away from the music and switch on the "audiophile ear", I can of course aurally walk right around the players. I have quite a number of recorded string quartets, where I can almost get the same result in front of my rig at home. There are a few recordings where the space between and around the players is even bigger. That may be very impressive but for the trained ear completely unnatural. So thinking along those lines, had I not been to many concerts I would be proud of how good my stereo is, but since I have, all this exaggereated three dimensionality makes me uncomfortable.
What happens if the hcat overheats and goes into a 4th dimension mode?

Is it a fire and brimstone thing or do you look for a parking space alongside Marty McFly's DeLorean?

Heavy stuff.
09-15-08: Pubul57
My impression is that my equipment is much more "holographic" than what I hear in live music (jazz, chamber), and live music is much more dynamic than what I can get out of my system.
Pubul57, I agree about the dynamics. I think it is basically how slow our drivers are. If you have ever heard the old Altec VATs or the Klipshorns with their compression drivers, you get close to the dynamics of real music.

I think that were you where the microphones are you would hear similar realism.
I've been working on the assumption for a long time that the "Absolute Sound" was the goal of this hobby, but I sometimes wonder why that should necessarily be, isn't it just possible that equipment might convey music in a way that might be even more enjoyable and communicative and not really by being an exact replica of live, just different and working on its own terms? I suppose the problem is that you loose the benchmark which grounds the subjective approach to a standard, and without it you really fall into mere opinion and preference - but I do suspect that many enjoy equipment that may fail by the AS reference, but succeed wonderfully on their own terms - especially in terms of imaging, soundstaging, etc - though I doubt you would want to veer too far from accurate timbre and timing.
Pubul57, your observation regarding holography and dynamics in live vs reproduced music is right on the money.

Years ago one of Stereophile's writer offered some perspective that I think is worth passing along, only I can't find the exact quote. But it went something like this:

"I am not so much interested in WHERE the musicians are on the stage as I am in WHY they are on the stage."

Duke
Pubul57 and Audiokinesis, I refuse to concede that reproduced music should be allowed to differ from real. We are seldom allowed to be in optimal locations at live events or to hear without amplification. There is an enormous thrill is hearing reproduced music at very close to what the microphones hear. I don't want to start the wars again, but this is what I am getting. I hope this will entice you to catch a listen.
Norm, with all due respect, let it stand. We have heard you. You do not concede. Fine. I have a reserved, favourite seat at our concert hall, classical unamplified music, mind you, and with my behind firmly planted in there and later just as firmly before my rig, I would contend, wether you allow it or not, it does. But let us not argue over this here, since it is off topic. Start a new thread if you like....
Norm, even with a temporary suspension of disbelief, reproduced music never sounds live to me; which doesn't mean it can't be very enjoyable and wonderful on it's own terms, but I'm never really fooled into thinking it is real no matter what equipment I've heard it on - but that is ok with me, I accept it. I think Duke's quote on "why" the musicians are on stage really captures the end game for what a great system can do for you - you get what the musicians are doing, what they are trying to say; even if it is not an exact replica of the live experience.
FWIW, the reason recordings don't have the same perspective that you hear in the concert hall, that you have a greater holographic quality in them than in real life, has to do with the microphone placement and post processing (if any).

Try spending some time with the mics at live performances and you will see what I mean real fast. Having a recording that you have taken from the live performance to CD or LP is immensely useful in developing a reference- it makes a difference when you were there and know what it was supposed to sound like.
Detlof, yes I believe there can be such thing as "too much holography". For example, I've heard at a friends house a pair of the old Beveridge SW2 electrostatic speakers. Everytime you hear music it's as if the performers are projected in front of the speakers, floating within a rectangular shaped space. This was for me the ultimate holographic imaging, like the Star Trek Holodeck, like a LSD trip. Personally I think this is too much of a good thing (unless you are addicted to it) and unlike the real life situation. I think the objectivists among us do not believe in "holographic imaging". They believe holographic imaging is always an artifact or the result of phase distortions.

Chris
I'll take timbral accuracy, dynamics and timing over holography/soundstaging any day - if I want to know what the musicians are saying (why they are on the stage). Ralph, is there any reason why the two may be mutually exclusive - that is, does the most accurate equipment in terms of one mean a lessening of the other?
Pubul57,
I like you have been working on the same assumption, especially so, since I am in the lucky position to compare the facsimile of certain music taken from a certain hall with the real event. I started our hobby at a time, when audio writers, having heard live performances say in NY or the CSO in Chicago later compared what they had heard on their Shaded Dogs, Mercuries or their 6 eyes. These days are long gone and Norm has a good point in saying that it is difficult to find a good spot in a live venue where to compare from. I think as you do, that many enjoy their equipment even if they have rarely been to a live event. That is perfectly OK. However, if you don't have some approximation to some sort of benchmark - and basically for me it is still the AS, the "gestalt" of live music out of a huge number of live events, which I carry mnestically in me - you open the door to absolute subjectivism, which is also all right, because we all hear differently with different preferences and different experiences of what we think music is and should be. This makes Audiogon both lively and amusing. In the olden days recording engineers were trained in musicology, you had to have credits in both fields to get a top job with DG, RCA, Phillips or Capitol. Quite a number of reviewers who I found I could trust, were musicians. To this day I prefer manufacturers, who play live music, do not only listen to it. One of them posts here. You guess who it is (:
is there any reason why the two may be mutually exclusive - that is, does the most accurate equipment in terms of one mean a lessening of the other?

My experience is they are hard to find. Most horns give you dynamics of live music but lose that natural sound due to narrow dispersion. Most well designed dynamic loudspeakers have the wide dispersion to sound natural and image precisely but lack the dynamics of live music.

Of course there are a few horns and a few dynamic speakers that do an admirable job at both and sound extremely convincing as if you are there - but it is only a very few, IMHO.
Tvad, this moving of the image to in front of the speakers and way outside the speakers it typcially achieved with out of phase signals or room interactions. "I Robot", DSOTM and "In Rainbows" are recording examples that should fill a 180-degree image from the listening position in two-channel stereo, because the engineers added lots of phase anomalies in mixing.

To the outer edge of the speakers and with lots of depth from the front plane to beyond the rear wall is more typcial. It's unrelated to tubes vs. SS, IME.

When you start hearing an unusually large image (well beyond the speakers and/or with unusual height) that'll be due to some phase anomaly and it's usually not "accurate." A high ceiling (particularly with a dome), oddly shaped sidewalls and other room irregularities can contribute hugely to this. If you hear it due entirely because of electronics, then there may be some designed in phase shifting to create more than is really there on the recording. Carver actually made a living for a good while doing this.

It's not a tube vs. SS thing. Put ARC and Rowland side by side and you may notice some very small imaging differences, but one won't be "holographic" and the other not.

Dave
Shadorne, "do an admirable job" "very few" those are good terms. I think speakers are basically "pick your poison." I have three times gone back to compression drivers in horns and three time abandoned them. I have four times tried horns with other drivers and retain one. I have had had two single driver systems which were outstanding by way of having no crossovers. I have had ribbons, electrostatics, and many multiple dynamic driver systems. I have even had two pair of omni-directional systems. My quest is discontinued now as I am retired, but I don't find the solution to realism is to be found in ideal speakers or even those that do an admirable job.
Shadorne,
Agreed, the bigger a-Capellas though will give you a very natural sound, but they are expensive. I found that the Sound Lab U-1PX makes for a good compromise. They have good dynamics and dispersion and if properly placed, image very well.
Tbg wrote: "Pubul57 and Audiokinesis, I refuse to concede that reproduced music should be allowed to differ from real..."

AudioKinesis responds: Kindly refrain from making "straw man" arguments. That's where you attribute to the other person something that he did not actually say, and then argue against it.
Audiokinesis, you say,"Years ago one of Stereophile's writer offered some perspective that I think is worth passing along, only I can't find the exact quote. But it went something like this:"I am not so much interested in WHERE the musicians are on the stage as I am in WHY they are on the stage."

Perhaps, I misunderstood why you quoted this.

No strawman argument here.
Tbg, I can see now how you misunderstood me.

Holographic localization of sound sources is not part of live music under most circumstances, but natural timbre and dynamics certainly are. Now I have nothing against holographic imaging, but it has never been part of my experience of "real music", so like the Stereophile writer I do not give it equal priority with other things like natural timbre and dynamics.

Duke
dealer/manufacturer
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Tvad said:
"Now, having just owned an ARC Reference 3 preamp, I agree it does not create a holographic image. Nothing as compared to the Atma-Sphere MP-1 or Lamm LL2 Deuxe preamps I owned."

So you're saying that you prefer the Atma-Sphere and Lamm to the ARC??

Dave
Duke, I agree with you and what seems strange to me is the value we (me too) place on "holographic" effects in our stereos when they don't seem to be part of the live experience to my ears. I suspect the reason is that in live music you can see the performers, you don't need auditory clues for localization, you simply see it - we may be trying to make up for that.
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No recording will ever capture the same spatial cues and no system will ever present them to you equivalently as occurred when your ears registered them live. So I believe its a pipe dream to think that any system is doing this accurately.

Given this, I believe its each person's choice regarding how they prefer the musical image to be presented to them, holographically or otherwise. Choose your technology and resulting distortions of preference...in the end its our individual perceptions and opinions that makes the real difference in regards to musical enjoyment or no.
Pubul57, I hear about timing a lot these days but its one of thoese things that I really can't say what causes it, although I do know that a lot of circuit complexity does prevent it. I don't like the word 'dynamics' as too many times I have found that audiophiles use it when what they really should have said 'distortion'. So I like to use the words 'impact' and 'authority'. Impact is the ability to respond to intense dynamic change, and authority is the ability to sustain it in the way that the source demands.

Both seem to arise more easily if the circuitry is kept simple, and certainly avoiding loop negative feedback will make the circuit more responsive to dynamic change.

As I have mentioned before, imaging and soundstage seem to derive from bandwidth, extending well beyond audibility. Oddly, what a lot of people would describe as holographic, wherein the image places *in front* of the speakers, or there seems to be unusually wide soundstage effect, nearly always seems to come from phasing anomalies near the edge of the passband. For example, as much a fan of tubes as I am, a tube amp that has poor high frequency bandwidth deriving from its output transformer can exhibit a form of this behavior. If they have good bandwidth, nearly all amps will image in a very similar way, with the variations being in how well they can render the individual images as 3D entities rather than as a cardboard-flat images, and how well the more subtle ambient cues are articulated or truncated, depending on how well the amp can reproduce detail.
Quote from a ultra high-end German manufacturer (with regard to their top-of-the-line power amplifier):
"...but this was not the point: it just plays even more relaxed, controlled and holographic then the stereo version."
Here being more "holographic" seems to be a major criteria to depict that a unit sounds superior to the other :)

Chris
Tbg,

I know I'm right in regards to reproducing what a person hears at a live performance. The way most recordings are miked, the geometry involved in detecting sound is different than that involved with human ears, I think that is a fact.

A system should have a good chance of reproducing to some degree of accuracy what the mikes actually picked up though, spatial cues included. That is the best you can hope for.

When you hear holography on a system for whatever technical reason, it is the perspective of the microphones that is being reproduced and this is always different than the perspective of the ears. That is a geometric fact I believe.
Ralph, impact and authority as you describe it is a very good way to describe what I mean by dynamics and related it to that is what I call microdynamics (there might be a better word) which is the ability to resolve small changes in volume and small changes in pitch that can sometimes be obscured - and that too might be related to distortion and/or poor S/N. These two aspects of reproduction are very important to me. I also enjoy the "holographic" trick as long as it doesn;t effect these; whether the holography reflects "live" or not.
I agree with Mapman here - the human ear is a much more sensitive instrument than any machine yet invented. No audio equipment I have ever heard or probably will ever hear can recreate the sound of a live performance.
TBG, you have a beautiful looking system, which I'm sure sounds wonderful - would love to hear it cuz I too have never been "fooled" into thinking a recorded performance sounds live (live-like yes), but if you system makes you feel that way, more power to you. Enjoy.
Tbg, I would like to join Pubul57 in sincerely wishing you as much satisfaction with your system as I draw from mine. After all, last not least also thanks to your postings, most of us have come to a reasonable and working definition what holography is, how it could be achieved and what its value and merit may be vis a vis the life event. As you may have guessed, I hold most of your arguments untenable, but generally, conflicting opinions not only help in the realization where one stands, the ensuing dialectics help to advance knowledge.
Happy listening
Detlof, I return your sentiments. I never intended to advance knowledge, however, only to reveal my experiences.

Happy listening to you also.
Pubul57, Something fun to try is to listen to a live performance and see if you can place the mics in such a way that a 2 channel playback over speakers has the same perspective as your ears. This is usually not an easy thing to do, but when I was preparing to record Canto General, I had convinced the ensemble to rehearse for the final week in the concert hall. So I had a week to goof off with mic placement, set up a nice playback rig on location and the like.

IF you have time to do it, a recording can be made that will sound remarkably like what it sounds like if you were sitting where the mics are. In most recordings, the mics are often **above** the ensemble, which produces an odd perspective, unless you happen to know that that is where the mics are placed.

Modern mics are remarkably sensitive- with them you can hear things in the hall that you would not notice with your ears! One time I had robins chirping in the mikes- hear it as plain as day over the monitors, but stand by the mic stands and you could not hear them. I found an open door in the rear of the hall... the robins were outside.

Another thing to keep in mind that will help you understand how realistic or not a system is being, is the model of what it should sound like. Don't think for a second that the system is going to sound like the hall- it isn't. It **can** sound, and very convincingly, like your listening room is grafted onto a space (which might be a hall) wherein the music is happening. A real hall will have hall sounds beside and behind you. Your system will have the real hall sound in front, but your room sounds beside and behind you. If you keep this model in mind, you will see that we are a lot closer to the Absolute Sound than most folks think. For a long time and to this day, the bottleneck is the media, not the playback!
Thanks for your contribution here Atmasphere. Several in this thread don't seem to appreciate or understand your contributions, but your input is very useful and your actual experience is particularly valuable to me.

The thread shows that some audiophiles are clearly enamored with holography, whether accurate or not. You explanation of why some tube amps add holographic effect help me what I've heard in a few amps, but didn't understand.

Dave
WOW!! This is sounding like a cable thread I see on other forms.

Prove it, prove it, prove it!!

If you hear a difference, buy it, if you don't then move on.

Or maybe ask Ray Kimber to prove his cables are better than then others.
Ralph,
The setup you describe reminds me of the "Kunstkopf" experiments, done in Germany in the 90s. The results were fascinating as far as ambience rendering of the recording venue was concerned, but you had to wear special earphones to really appreciate the results. That was the reason that this technology never hit the mainstream. The few recordings that were made are collectible items now.
According to my long listening experience I would intuitively agree with you, that the media constitutes the biggest bottleneck for realistic rendering and indeed, as you also have suggested, I've been battling with my various rooms all of my audiophile life to minimize its interference. A task comparable to that of Sisyphus indeed!
Your tale about the chirping of the robbins makes me think as well:
I've been complaining quite often here, that what keeps us most away from the "Absolute Sound" at home,is what I call bloom or aura, that magic moment, where a note played, say from a solo violin spreads into space, emanating almost from all around the instrument. That is something distinctly different, I think, from what we have discussed here. Too much of holography spoils this by masking just that effect.
Quite possibly you are right, that it is the media, not the gear.
I do not have one CD that can do it. Mostly to mimic that effect, they mix in a bit of hall around the voice or instrument, which I find annoying. I know of a large number of classical piano recordings on LP, where you hear exactly where the right pedal sets in, but that is not quite the same thing either.
If it is the medium and not the "messenger"-rig, do you know of media that do truly render this "bloom", which apart from room-interference, as you so rightly point out,is to me the biggest obstacle to the "Absolute Sound" at home?

Cheers and thanks for your most valuable inputs here!
Detlof
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>>I never intended to advance knowledge<<

I don't think anybody expects that is possible.
"Don't think for a second that the system is going to sound like the hall- it isn't. It **can** sound, and very convincingly, like your listening room is grafted onto a space (which might be a hall) wherein the music is happening. "

Another great point by Atmasphere.

This is very doable. This is what I tend to shoot for with my system in order to be fully satisfied with what I hear.
Detlof, in working with CD and LP mastering and with digital and analog master recordings, over and over again I am always struck and disappointed by the signal losses that occur during the mastering process, regardless of the format. If anything, the CD format seems to loose *more* during the process of going from master to produced copy than seems to happen with the LP.

When you are listening to the direct microphone feed, and then compare that to the results of a digital master file or a 1/2" analog master tape (regardless of tape speed) there is always a degradation noticable there too.

If you are familiar with this degradation, you can compensate **slightly** for its loss by microphone placement, but its tricky and most engineers will not take the time. I think this and the above phenomena is why there so few truly exceptional recordings, **especially** when you factor the performance into the equation!

When it comes down to it, I'll go for the performance nearly every time, and simple deal with whatever vulgarities the recording is otherwise. Such a world!
**above** the ensemble, which produces an odd perspective, unless you happen to know that that is where the mics are placed.

Wood floors and microphone height above floor are key in recording. The floor will produce comb filtering as the sound is reflective from it and cancels with teh primary sound - it creates a pleasing spacious sound. Depending on the instruments there are a variety of rule of thumb positions for mics - choral works are often recorded with overhead mics.

BTW - this happens with your speakers in your room too particularly in the low midbass where soudns radiate in all directions => you get quarter wave cancellations off the wall behind the speakers.

They key to this effect is a large flat reflective surface which is positioned symmetrically with repect to the microphone or listener. Some sudios have special plates just for this purpose although often recordings are now made in a an acoustically dead booth and th esoudn of a platye is added by using a reverb (the advantage is you can dial in any reverb you want)

For example side walls do not produce this effect in a listening room - only the rear wall behind the speaker and listener which is symmetric with the bass and midbass frequencies. It is the same for a microphone - if you want to maximize the effect then the mic needs to above the source of sound so that the sound is in between the microphone and the reflective floor.

I recommend Bob Katz book (Mastering) for people who want to read up on this. I am sure Ralph knows more than I do about all this - but I thought many readers may be unaware of this - although as an audiophile I think it is only natural that one should want to understand this stuff (nearly half of what we ever hear is reflected sound)
>>when it comes down to it, I'll go for the performance nearly every time<<

Ralph, how very right you are! Most of us, who love music, would not be in this hobby, if this were not so. It is those moments of bliss, where you forget about your rig and get drawn into the music, which makes this all worth while!