Holographic imaging

"Holographic imaging", or transparency as it is often referred to, is an artifact of a combination of system and room acoustics resulting from speaker placement. Its not due to SS or tubes. Either may or may not image "holographically" depending on other factors.

The main pre-requisite for holographic imaging is that the sound not arrive at your ears primarily from the direction of the speakers alone. Another is that there is good stereo separation between speakers and that signal is relatively clean and not overly polluted with distortions.

Dazzdax,

One thing I think I would say with confidence is that you won't get holographic imaging if the sonic queues needed are not in the recording even with tubes.

If that's what you're hearing, its encoded in the recording and your system is decoding it and your room acoustics are enabling you to hear it for what it is.

Tubes may add the "bloom" factor which can sound pleasing to many, but it is not the same thing.

Dazz,

I think many refer to what you describe as "bloom" and yes, it is more associated with tube gear than SS. I believe it has something to do with the way various harmonics are presented in general with tube gear versus SS.

DC,

If you read my second to last post here I think you'll see we agree that "holographic imaging", assuming this refers to transparency, is more of a room and acoustics thing and not an artifact of SS versus tube.

Newbee, I think I generally agree with what you're saying but can you please explain the assertion that omni's are not inherently capable of holographic imaging? I have never heard a pure omni design, but I would expect them to be inherently more capable, when set up correctly, than more traditional designs.

By the way, holographic imaging is a somewhat vague term not commonly heard in these audiophile parts.

"Holographic Imaging" is a specific feature on Carver pre-amps that you can switch in and out as desired.

I am very familiar with this effect from living with a Carver pre for many years and through various system incarnations. The resulting sound, on a properly set up system, is much like Newbie describes.

I've found other ways to accomplish the same effect without using the holography feature on the Carver and do not use it at all these days. My system is all SS and no tubes (so far).

Newbee,

The "holography" you describe is consistent with speaker configuration parameters that I found worked best with Carver sonic holography. It works better with more directional box designs, particularly when approximating a point source.

It worked best with my Dynaudio and Triangle monitors. It also worked well with Maggies I owned for many years but these were trickier to get set up right for best effect. I could never get it to work well at all with larger B&W floor standers I owned.

It does nothing useful for the Ohms which are pseudo-omni directional as you describe.

These are totally transparent and with well produced recordings, the musicians are located precisely and in various locations within the huge soundstage and with considerable variation in depth of location as well.

I don't understand how the dispersion patterns of omnis is a problem in this regard. Doesn't the principle of triangulation come into play with sound? Doesn't sound reaching your ears from multiple directions inherently make it easier to determine location in 3 dinensions?

3d glasses used to view images in 3-d use this principle to work.

How can sound reaching your ears from 2 speakers produce any information on their own regarding depth?

Also , how does it work that you can locate a guy in a room playing violin say? The sound eminates in a largely omnidirectional manner and reaches your ears more like the way it does with omnis. Its not beaming directly at you alone like most speakers.

I think omnis have a unique type of 3 dimensionality. Holography is probably technically a different thing but similar in effect.

I'm still not sure holography is the same thing as transparency, which can be achieved with a variety of speaker designs as well, but I think the effects and benefits are similar as well.

Here's one of the more interesting accounts of how depth and image in sound reproduction works that I've read.

http://www.morrisonaudio.com/morrison_donsview.htmth

Sorry, here's the working url:

http://www.morrisonaudio.com/morrison_donsview.htm

http://www.stereotimes.com/speak111607.shtml

This review asserts that the MBL omni design reviewed is, and I'm quoting, "holographic".

I would say the same about Ohms, only placement in the room is less difficult to achieve the results since the sound level is attenuated in the wall facing directions .

Newbie, I'm wondering if the omnis you heard were set up correctly? Which ones were they?

Newbie,

The Carver c-6 pre-amp in my system is SS but provides two separate preamp outputs: one "SS" and one "tube". Each is voiced differently. The "tube" voicing does in fact sound more tube like than the SS and that is the one I tend to use. I find it does add a certain additional harmonic richness to the sound more in line with what I hear and like with better tube systems I hear. I find adding that to the mix with the Ohms does have a positive effect that one might say makes things more holographic, but to me it is a different thing that adds to the mix in a unique way. Together, the end holographic effect is outstanding.

That has lead me of late to strongly consider trying a real tube pre-amp, something like a VTL perhaps.

I think holographic is a vague term that different people will associate with different things to suit their purpose as you point out, which is certainly true.

But I do have to point out that I think that your assertions that omni speakers cannot be holographic due to their nature goes against the reality that one can plainly hear for themselves if interested.

One thing for certain is that tube power amplification and most omni designs do not work well together due to the inherent power demands and difficult loads most omni designs like MBL and Ohm have.

The reality here is that tube lovers need not apply for most omni speaker designs. But that won't stop the omnis from achieving their inherent holographic imaging nature.

Some seem to think bloom may be one form of holographic imaging that is more associated with tubes, but I think only that not all holographic imaging is bloom. Holographic imaging can occur with or without tubes.

Honestly, I'm not sure exactly what bloom is. I've just heard people refer to it as adding some additional aspect of dimensionality to sound when present. Personally, I am somewhat ambivalent regarding bloom, though I do like the sound of good tube systems when I hear them.

Can you explain what you mean by either solid state or tube should be wrong then? I'm not sure I understand.

I think like DCstep in regards to only what you hear live as being "right".

But even 10 different live performances will sound different, just by performing each in a different venue.

Or you can stay in the same venue and listen from different seats/locations. Each will sound different. Which is "right"? The answer to me is: all of the above are equally "right", but still different.

What you hear on a stereo system, even the best with the best recording to work with, can only approximate though what you would have heard had you listened live, which is where music truly originates

Bose has never made a omnidirectional speaker that I am aware of.

Tbg,

I am of the opinion that a really good pair of horn loaded speakers might be the only design out there that might do it all as well or better (though in a larger package) and could lure me off of the Ohms some day.

Good omnis (Bose are not, Ohms are only pseudo-omni techically) and horns (from what I've heard) probably share little in common other than the ability to truly disappear and provide the illusion that the players are right in your room.

The Ohms in particular also have outstanding dynamics though they do require a lot of clean power in comparison to horns.

HAve you heard the Ohms recently?

DC, I haven't heard any horns recently at all.

But I've heard murmurings that designs like the larger Avantgardes, for example, when properly set up, can totally vanish and present the illusion that the performers are in your room.

I tend to believe that it is true but haven't actually heard it with my own ears.

I can say for a fact that this does happen with the Ohms.

Horns and omnis like MBL or German Physiks and even the Ohms are clearly two ends of the spectrum in regards to design, but I'm thinking they can achieve similar effects in regards to holographic imaging through different means.

DC,

Horns would achieve their "life like" tendencies more via exceptional dynamics I would suppose than necessarily via "holography".

I have this vision that the exceptional dynamics of a very good horn system with just even average holography would be a stunning combination. I am not so certain though that any horn design would blaze the trail though in regards to pure "holography". Also, most horn designs that I see that I think might be able to cut it are too large for me to even consider putting into practice in my house.

Horns are one of those areas in audio that I have not experienced to-date very much, but it is an area that I do have a lot of interest in exploring someday in greater detail when the right opportunity presents itself.

I've never heard MBL or German Physiks. I would expect to hear "holographic" imaging from these if set up properly, though my understanding is this can be hard.

Its interesting how peoples opinions of omni designs vary so widely.

I think it is a combination of these systems perhaps often not being set up properly combined perhaps with people having a hard time getting used to listening to them when there ears are trained to listen using more directional designs.

I know when I first received my Ohm series 3, I missed the sound that was being produced entirely despite having owned original Ohm Walsh 2's for years, along with several other makes and designs including Magnepan, B&W and Dynaudio.

I shook my head and asked myself whats going on, I must be missing something? It sounded like there was a stereo balance problem as well. The left side seemed to be producing more sound than the right, even though everything checked out and the system was properly balanced.

What I was missing was that I was expecting the sound to be emanating largely from the location of the speakers, as had been the case with the older Walsh 2s that sat in the exact location prior.

But in fact , the sound was totally disassociated from the speaker location.

In the L shaped room they were in, the speaker location was skewed completely to the right of center of an approximately 20' long wall, about 5 feet apart (in order to fire into the length of the L shaped room).

But the soundstage was in fact evenly extended from wall to wall despite this. And the individual instruments and recording elements were clearly located within the sound stage from left to right with height from ceiling to floor and considerable variability of depth. Mono recordings emanate actually from the left of the left side speaker, located dead center along the wall but entirely to the left of both speakers.

That is how I've had it set up and listen since. I am not exaggerating this. If that ain't holographic, I don't know what is.

My point is that the sound was so holographically disjointed from what I was expecting that I missed it completely at first. Once I figured it out and tuned in, it has been my live concert hall ever since.

The thing that threw me for a loop is that no speakers I had ever placed in that room similarly before, including the original Walsh 2s ever had this degree of disassociation between speakers and sound.

I used to be able to get it in my old house that had a large rectangular family room with my old Maggies. Could never get it in the new house...until I tried the series 3 Ohms. Now I own two pair.

Tbg,

I'm curious why you sound so down on German Physics? I've heard mostly good things about them but have never heard them. Their use of a specialized coherent source Walsh driver (the DDD) has special appeal for me compared to other omni designs.

Are you just not down with omnis in general, or do you find something particularly lacking with the GErman Physiks?

"You mention that ohms sound is disassociated with the speakers. That I believe is quite true but not real."

I'm saying it is "holographic" only in accordance with my understanding of the term.

I'd like to hear the sound quality on the holo deck of the Starship Enterprise though.

Reproductions look pretty real there from what I can tell on TV and I bet the sound is equally realistic.

What kind of speaker technology do they use I wonder? To the best of my knowledge, its never been stated.

I'd bet the dispersion pattern is omnidirectional though or wide dispersion at the very least......

Tbg,

You indicate you've heard MBL.

Have you ever heard Ohm or German Physiks?

I understand and appreciate that you do not lean towards the omni sound from ehat you have heard.

Personally I have heard Ohms only and like the wide range, wide/omni dispersion, highly coherent Walsh driver approach in general.

MBL uses multiple drivers in the Radialstrahler designs as I understand it to achieve omnidirectionality within a particular frequency range.

I am not a fan of designs that attempt to integrate many drivers in general, omni or otherwise, because believe it is difficult or near impossible to do well. maybe MBL does it better than most...I don't know.

If you have not heard an Ohm or GP design in particular, try to keep an open mind. I wouldn't equate all onmi designs equally any more than I would any other category of speaker design.

I've been considering a tube pre as well but would prefer to stick to SS as well.

What does H-CAT do that other SS pre-amps do not that makes it unique?

Actually, I just read about the H-CAT approach.

Seems like it requires careful "tuning" to provide the advertised benefit and that some have achieved "it" and some achieved something perhaps less desirable otherwise.

Definitely a different approach than Carver sonic holography, which the site correctly alludes to.

Having heard that the Carver holography does in fact work, I'll keep an open mind regarding this approach. Sounds like a different approach to lowering amp distortion than typical negative feedback approach as I understand it.

The site left the impression that earlier versions did not provide adjustment of the correction which is absolutely needed otherwise the chance of the gadget working was low. Assuming true, it was not very smart of the vendor to sell a gadget to audiphiles as such (missing a primary feature needed to work in most cases).

The Carver approach was technically not that complicated, yet effective. This approach seems much more complex and harder to get right, assuming it does in fact work. I suppose the only way to know would be to try it.

Does the vendor offer any kind of money back guarantee? I would think that might help entice those interested in taking the plunge.

Were I to go to a different SS pre today in search of better sound (rather than tube), I would strongly consider Classe based on what I have actually auditioned and liked.

By the way, on eother negative about Carver holography, for those interested, is that you have to have the speakers set up just right and listen from just the right position to hear it.

One of the reason I went with Ohm speakers is that I hated that aspect of the Carver holography to achieve the desired effect. With the Ohms, you get equally good holographic imaging as I described above from a wide range of listening locations in the room. I do not think this is possible in general with highly directional speakers (I've never experienced it) but I could be wrong.

Atmasphere,

My system is currently highly transparent and holographic, I would say.

But I've thought about trying a tube pre-amp with my SS amp to get more of the sound of tube harmonics going, which I tend to like as well when I hear a good tube-amp'ed system.

Do you think a hybrid approach like this is likely to result in a more compromised, middle of the road sound, or could it add a touch of tube-like harmonics in a manner that benefits without negatively impacting the good things already happening?

Tube power amps will not work well with my Ohm speakers I am convinced due to their low efficiency and somewhat difficult load, so that is not an option for me.

"The more transparency you get, where SS excels, the less air seems to be possible around the instruments. "

This is not consistent with my experience. I find "air" is more associated with transparency. It can happen with SS or tubes.

Regarding bloom, this term confounds me personally.

I have looked the term "bloom" up and cannot find a definition that pertains specifically to sound or audio.

I found this:

2. To shine; glow.
3. To grow or flourish with youth and vigor.
4. To appear or expand suddenly: White vapor bloomed from the side of the rocket's fuel tank.
v.tr.
1. To cause to flourish.

Make the emotional association of this with the sound you like as you will.

I suppose my system flourishes with vigor, so maybe its bloomier than I thought prior. Definitely holographic though...

Holography is a useful term for describing several attributes of good sound in audio together.

Carver's holography is an explicitly identifiable (analog) signal processing algorithm implemented in Carver equipment. When engaged, it improves the size of the sound stage and ones ability to identify specific players, instruments or recording elements within a more three dimensional sound stage. If you want things to sound more real, this is a good thing because these are attributes of a live musical performance as well that otherwise may often be lost with a 2 channel stereo audio playback system. It does in fact work very well when things are set up right and you listen from just the right place.

Carver is the only company that uses the term to describe a particular feature/function of their equipment that I know of, but I think the use of the term is the primary unique value.

Other equipment clearly achieves holography as well, through similar or different means perhaps, but they do not talk about much if at all, and the function cannot generally be switched in and out...its explicit in the standard operation of the equipment. Others more likely talk about the more commonly discussed elements of good sound that are typically present as well when holography is present, sound stage, imaging precision and detail, 3 dimensionality, bloom, etc.

Dave,

I'm not necessarily advocating Carver holography, although I think the processing it does makes sense, it works as advertised, take it or leave it, and the benefits can far exceed the disadvantages. In fact, I no longer use the circuit because it is not required with my current set up.

The only speakers I've owned prior to the Ohm series 3's that I never found any value with using the Carver holography feature were the Triangle Titus monitors, which are so fast and detailed that the sound achieved a highly transparent, holographic effect on its own. Not true to the same extent with any other speaker I've owned including Dynaudio, Magnepan, and B&W or even original 80's vintage Ohm Walsh 2's.

Nothing that I've heard does holography as defined below (from wikipedia) as well as the Ohm series 3. You can move around the room and the perspective of the sonic image will change with you accordingly with little or no degradation.

Carver holography cannot do that. You have to listen from exactly the right spot otherwise the phase aspects you speak of come into play in a negative manner, not positive.

Let's face it that the whole concept of listening to music via a stereo system is in fact artificial and each system sounds different. All that matters is the end result and does it sound good to the listener.

I like the term "holographic" in describing audio though in the general sense that it captures multiple factors of good sound in a single term that describes what is needed to reproduce the complex live listening experience which is inherently 3 dimensional out of two boxes sitting in your room that inherently are not.

If a system does things well, there can be a holographic aspect to it that is a cumulative result of many other factors that we commonly discuss regarding good audio.

The end goal for everyone is this hobby I think is to make the reproduction of music in our rooms as real as possible. How can two little (or big) boxes capture what you hear live in 3-dimensions without the concept of "holography" coming into play?

A lot of things have to be going right for it to happen, and yes, there will always still be some things that do not go as "right" as others.

Below is the definition of holography from wikipedia. From this definition, how can holography be categorized as a bad thing when it comes to audio?

"Holography (from the Greek, όλος-hòlòs whole + γραφή-grafè writing, drawing) is a technique that allows the light scattered from an object to be recorded and later reconstructed so that it appears as if the object is in the same position relative to the recording medium as it was when recorded. The image changes as the position and orientation of the viewing system changes in exactly the same way as if the object were still present, thus making the recorded image (hologram) appear three dimensional. Holograms can also be made using other types of waves."

Actually, after reading the wiki definition of holography, it is probably a misnomer to call what the Carver circuit does "holography" because it only works when listening from on spot. You can't move around and get different perspectives.

based on this definition, I'd probably now asset that the only way you can get coherent holographic perspectives from a variety of listening locations, as is required by the definition, is with omni, pseudo-omni, or other very wide dispersion speaker designs that might be out there. Professional reviews of omni speaker designs always allude to this as one of the most unique aspects of these designs.

With their application of the highly phase coherent Walsh driver design, I suspect the Ohms and German Physiks are inherently capable of doing it best.

Tbg,

Read the definition of holography and then listen to a pair of Ohms and then we can discuss whether or not it is holographic.

Is there a system out there that can be measured in such a manner as to quantify exactly how it sounds?

Can systems be ranked accordingly on how good they sound based solely on measurements?

Can anybody explain to me how a $1000 power cord works differently/better than a $20 one made out of teh same stuff?

I'd say a many parts of high end audio is more based on faith and beliefs more so than measurements.

Tvad,

I'm probably more in the first camp in terms of how I set up my system, but the inherent flawed nature of many of the recorded musical performances that are my favorites forces me to be content in the second when needed. For example, I have no control over how many of the early Beatle's recordings in particular were produced. I have to accept the limitations of the sound because the music and performances are exceptional and make up for the lackluster sound.

I am happiest though with great music and performances that also happen to be well recorded so I can in fact practically exist in the first camp.

I am a music first guy. I will not not listen to something just because it sounds "recorded". I'd rather it sound more "lifelike" if it could, but it is what it is.

Newbee,

I'm undetered because I've heard a lot of variations of very good live and reproduced sound over the years and know that there are many ways to skin a cat. We each make our own best informed choices.

TBG,

Agreed that there is a thrill to realism in an outstanding performance.

Newbee,

My eyes tell me that I would also much prefer to see Penelope Cruz.

Hopefully my eyes are not as deluded as many seem to think are my ears.

Back to Dazzdax original inquiry, I suspect the tube-associated artifact in question is not holographic imaging and more likely what is commonly referred to as "bloom".

I don't think that holographic imaging is an artifact of tubes at all. Bloom often is. I would agree with Dave also regarding the relative sonic merits of bloom in general and how it becomes less of a distinguishing factor in better gear.

TBg,

Believe me I'm not interested in arguing either, but realize that the definition I provided is not mine, I'm just sharing it. Take it for whatever its worth.

I'm just trying to help provide some clarity in terminology where it exists so as to help cut to the chase rather than argue what certain words mean.

Personally I learned from it that Carver holography really isn't holography at all. Its just one engineers approach to providing a bigger sound stage with improved 3-d imaging if that is to someones tastes. Obviously, its not to many, at least via the means provided.

I have been strongly considering trying a real tube pre on my system.

I prefer the tube voiced output on my SS Carver pre to the SS one on my system currently. I'm thinking it could add a useful ingredient to my audio soup, maybe just a small pinch of additional "bloom". I've considered Acoustic Research, CJ, Unison, VTL, and DeHavilland.

Classe is one brand of SS pre that I would also consider trying from what I've heard.

I'm open for suggestions on this if anybody has some.

" I have found that putting sound out in front of the plane of the speakers is more related to speaker design (I have only experienced this phenom with a horn/cone hybrid and it a general soundfield attached to most recordings. But it was fascinating especially with that old Carver 9 holograpy machine in the loop). "

I have heard it to a huge extent recently in a dealer showroom using Krell 400xi integrated driving either Martin Logan electrostats or Focal dynamic/cone designs. Which speaker made little difference.

I think it had something to do largely with room acoustics as well, in other words, the portion of the room behind and to the sides of me was "hot" or very lively in relation to the area behind the speaks.

Unsound,

I've heard Ohm CLSs outdoors and they sound best, very close to lifelike, with just a single wall behind them. They also tend to like larger rooms in order to have sufficient "room to breathe".

True omni's should not be placed close to walls from what I hear.

One advantage of the Ohm pseudo-omni design (for two channel stereo systems they are physically attenuated with sound absorbent material inside the "cage" in the wall facing directions as I believe you know) is that they can be placed within 2-3 feet of walls where they tend to sound much like more conventional box speakers with very wide dispersion and the huge soundstage.

I don't know for sure whether the H Cat does what it claims or not since I've never heard.

But my understanding from their web site is that they sold early models of a device that requires adjustment to work right without any way to perform the needed adjustment.

Oops????

Theaudiotweak,

I agree with the merits of fessing up to a mistake, but given the apparent severity in this particular case, what other option is there?

At least it sounds like it has a chance to work now if adjusted properly.

I guess the only way to know would be to listen and compare.

Still not sure though how this is better in practice than negative feedback? Sounds like a tricky proposition to get right, certainly harder than providing an adjustment.

Need to give it some more thought.....

Roger_paul,

Interesting.

Is doppler effect in an amp a different problem than the one solved by application of negative feedback? If so, how much is it different in terms of the effect on the sound?

Thanks.

Sounds like a common theme is low distortion is good for holography and each company/designer has their own ways of dealing with the distortions they care about most.

Each approach has up and downsides. Which is best? Who knows and who cares.

If your getting good "holography" on your system, then whoever designed your amp is probably doing a good job of dealing with distortion in a manner that delivers positive results effectly.

Nothing new here. There is seldom ever a single approach to anything that has all the benefits and none of the disadvantages. So I wouldn't lose any sleep wondering who does it best. Just listen and judge for oneself...what else is needed?

I owned a Hitachi Class G receiver once back in the 70's when I lived in a dorm and wanted high power in a small package. It had some good attributes but for whatever its worth I would say low distortion and holography were not this piece's strength compared to most every other piece I have ever owned..

"then an amplifier should sound "flat", because that is closer to the truth"

You lost me on this. Why do you think "flat" is closer to "the truth"?

What "truth" are you referring to?

Musicians perform and sound waves propagate in 3 dimensions last time I checked?

Not that "holographic" necessarily equates to truth either, but I can't see how "flat" could be closer to the real truth either.

Your not just yanking our chains for fun, are you?

"Not that "holographic" necessarily equates to truth either, but I can't see how "flat" could be closer to the real truth either."

Actually I can think of a way. That would be assuming "flat" refers to a projection of the original 3-D sound onto a flat plane, much as portions of the real earth are projected onto paper maps.

In this case, realize that projected representations of 3-d objects onto a map are inherently and by design distorted reproductions of the real thing.

By the way, I agree with Tvad.

As long you like what you hear, it really doesn't matter what other people think is best.

If you think flat is more real, then more power to you.

Personally, I'd rather deceive myself into thinking I can do better since I've been given an additional dimension to play with, but then again I also like Pro Wrestling.

"You would agree that the act of moving away from a sound source makes the frequency/pitch appear lower?"

No doubt.

I need to think about the volume knob analogy some more though since that would seem more relevant. I'm thinking Roger paul is right on this one though....

We may be entering the Twilight Zone....where's Rod Serling?

Roger,

I understand your descriptions of Doppler effect in regards to sound waves propagating outside of the amp, nothing new there, but not how the same thing occurs in the electrical domain within the amp.

Atmasphere's questions seem relevant.

Wikipedia section on amplifiers talks about a lot of things including use of negative feedback but Doppler is not mentioned.