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Do loudspeakers need to image precisely?

watchnerd

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#81
I think precision in speech is important, and I didn't say that this was true unequivocally. Some do, some don't. I've noticed that amateur or student orchestras often play in churches so reverberant that its difficult to hear individual flubs. I wonder if this is by intent? I recall seeing one university concert (Shostakovitch) where a cello was playing solo but accompanied and I could see the bow move but couldn't pick the cello out of the reverberant sea of bass and viola. The venue was "forgiving" and larger sounding than most, maybe akin to unresolving and euphonic audio gear. For these orchestras, the synergy works.

OTOH, sonics are glorious at the following church, for chamber music or choral. I've been to many concerts here and even the balcony sounds fantastic (which is the opposite of our orchestral hall)
https://ottawacitizen.com/news/loca...rees-to-talks-to-buy-dominion-chalmers-church

The top chamber groups usually play there (I just saw Romeros a couple weeks back). The venue is starting to be used for orchestral works, and it'll be interesting to see if it can contain the larger scale without getting mushy.
IME, big old mosques are even more amazing, possibly because they were designed to let the adhan carry well.
 

Ron Texas

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#82
IME, most of the jazz recordings from that time are almost exaggerated pingpong. Lots of hard left, hard right stuff, maybe to show off the stereo effect. I assume that the classical recordings from that era better?
I have heard the ping pong effect, but not in a majority of Jazz recordings. Sometimes there is a lack of a phantom center channel. In many recordings these things were fixed when remixed for CD. The classical stuff is definitely great.
 
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DDF

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#83
IME, big old mosques are even more amazing, possibly because they were designed to let the adhan carry well.
Interesting, thanks, I'll look for performances in mosques.
BTW and OT, but I completely agree with you about Harry Pearson. IMO he almost single handedly destroyed this hobby and I think there's a direct evolutionary connection between his "I hear it so its true" approach and the fact that companies are now shipping s*&t.
 

garbulky

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#84
Unless your listening room is anechoic, what you're hearing on playback is a mashup of the acoustic venue of the recording and your room.

Now, I'll agree that can sound pleasant and convey emotion. But it's an artifice and not strictly accurate. Play that same recording back in a different room and it will sound different.
No doubt the room has a huge contributing effect. But you can still get a surprising reproduction of the recording's ambience and venue dimensions in your room. At times it can almost feel like the walls aren't there depending on how convincing the illusion is. But it takes a lot to get there. For a long time I was able to get the singer or instrument in the living room with a general sense of the room venue. But more recently I have been able to get a better sensation of the living room becoming the venue and that's when imaging becomes fun!

A guy I know has a set of Thiel CS5i flagships and it is stunning what it can do when he positions it carefully and uses room treatment. He showed me a stereo recording of seagulls at a beach which he took standing in the ocean. And I closed my eyes and it felt like I was at the beach listening to a huge acoustic space as if the room wasn't there.

I have done many recordings in my listening room with the mic in such a position that when I listen to it from the speakers it is close to the reflection of the microphone from my sitting position. So that's as close as you can get to the original acoustics. Still not perfect as you are still having the original reflections interacting with the room. Some nice headphones can also give you a sense of the room's acoustic contribution.
 

watchnerd

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#85
I have done many recordings in my listening room with the mic in such a position that when I listen to it from the speakers it is close to the reflection of the microphone from my sitting position. So that's as close as you can get to the original acoustics.
Agreed.

This is the process I use for microphone selection.

I do it now using my bass, but plan to transition to using a player piano when it finally arrives / I get it installed.
 

Stonetown

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#86
What are you using?
Hi. I am using Swedish built speakers from the 80s. Brand: Audiotronic, Model: CM3, 4 pcs. They are each 1 meter high and I put one upside down on top of one so we have little more of 2m high speaker. The speakers are 2 ways transmission line with two KEF B200 and one Gamma ribbon VLD13 in each. Putting the top speaker upside down makes the element sitting closer to each other so the ribbon tweeters are in vertical line and so also the four KEF B200 in a vertical row on each side/channel. The CM3 speaker is highly directive alone but stacking two like this makes the pair even more directive in the vertical plane. CM3 speaker is specified to 22-20000 Hz +- 3dB. 96dB/1,2W. I built a single front to cover the both speakers so it looks like a tall 2m high single speaker :) See pictures. Currently I am driving them with a Denon POA-2400/ PRA-1500 together with Topping DX3Pro DAC. Sometimes I hook up a stereo tube amp with 8xEL34 in class A triode connection. It sounds good also. Sometimes I have also the Technics SE-M100 amp with built in 2 by 2 pcs Burr/Brown PCM56 DACs, connected. Also sounds good. I can't decide what Amplifier to use hi :)
Edit: I attached also a measurement with my RTA. The measuring microphone in same position as I have my head when listening, all speakers driven in parallel with noise. I think it is not bad for an actual listening room. The dip around 100 Hz is probably windows resonating and letting those frequency getting out from the house. A common problem.
Anyway the big thing is that the speaker elements and their configuration all together makes them very narrow and I love it! However I must have my head within +- 10 cm (4") sideways.
 

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Sal1950

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#87
IME, most of the jazz recordings from that time are almost exaggerated pingpong. Lots of hard left, hard right stuff, maybe to show off the stereo effect. I assume that the classical recordings from that era better?

I do remember Gordon Holt complaining about multi-miking classical stuff back in the mid to late '60s, so any simplicity in recording didn't last long... That said, the multimiked recordings from John Eargle are fantastically good.
Once multitracking, large consoles, etc became the norm the engineers just could resist playing with the toys. Most classical stuff today is heavily mic'd also, with the engineers showing maybe a bit more restraint that the guys sitting at the rock nuclear powered 192 channel mars rocket consoles. :)
 

watchnerd

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#88
Hi. I am using Swedish built speakers from the 80s. Brand: Audiotronic, Model: CM3, 4 pcs. They are each 1 meter high and I put one upside down on top of one so we have little more of 2m high speaker. The speakers are 2 ways transmission line with two KEF B200 and one Gamma ribbon VLD13 in each. Putting the top speaker upside down makes the element sitting closer to each other so the ribbon tweeters are in vertical line and so also the four KEF B200 in a vertical row on each side/channel. The CM3 speaker is highly directive alone but stacking two like this makes the pair even more directive in the vertical plane. CM3 speaker is specified to 22-20000 Hz +- 3dB. 96dB/1,2W. I built a single front to cover the both speakers so it looks like a tall 2m high single speaker :) See pictures. Currently I am driving them with a Denon POA-2400/ PRA-1500 together with Topping DX3Pro DAC. Sometimes I hook up a stereo tube amp with 8xEL34 in class A triode connection. It sounds good also. Sometimes I have also the Technics SE-M100 amp with built in 2 by 2 pcs Burr/Brown PCM56 DACs, connected. Also sounds good. I can't decide what Amplifier to use hi :)
Edit: I attached also a measurement with my RTA. The measuring microphone in same position as I have my head when listening, all speakers driven in parallel with noise. I think it is not bad for an actual listening room. The dip around 100 Hz is probably windows resonating and letting those frequency getting out from the house. A common problem.
Anyway the big thing is that the speaker elements and their configuration all together makes them very narrow and I love it! However I must have my head within +- 10 cm (4") sideways.
Thanks for sharing! That's a pretty funky.

Why is there a sheet on top of one of the speakers?
 
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#89
Thank you to everyone posting here, these are some very interesting insights and perspectives be expressed.

I just wanted to introduce a related concept that I haven't heard discussed

Siegfried Linkwitz (RIP) has some very definite ideas about what speakers should do. His ultimate designs are open baffle. (I've never heard such speakers, but really want to.) His website presents some very detailed explanations about sound presentation that are over my head, but I'm trying to chew through them. A lot of food for thought here...

http://www.linkwitzlab.com/speakers.htm

But part of his ideal is that the speakers should "disappear," leaving an experience of a kind of three-dimensional illusion for the listener, in the space. I am dubious.

He does seem to reflect that the best speakers should reproduce the illusion of a "live performance." I think this is a very narrow view, as soon as you step outside the realm of naturalistic recordings of acoustic instruments. (IMO, these type of recordings are easier to create and reproduce in general.)

I've never shared this perspective on what a playback experience should be, because to me recorded music is music. Most of my relationship with music is of the recorded type. Live performances are hit or miss, at best. (Well, records are too, but you can just turn off a bad record:)

Speakers that "image" well can produce an illusion of, for example, a violin in a room. In this case, if the speakers reach this "ideal" and disappear, the illusion is that a complex three-dimensional object, made of wood and metal, is actually the resonating object in the room, not the speakers.

This approach falls apart with most rock music or multitracked music. The problem is that the actual "resonating object" that is the medium upon which the artists construct their product are the monitor speakers in the control room!

One of the weird aspects of multitrack recording is the ability to superimpose instruments that naturally have very different SPL in a single recording. For example, you can combine a mandolin with a marshal guitar amp.

Then think about it: in a typical "pop" recording, we have a lead vocal floating on the top of instruments that generate far more sound energy!

To combine these disparate sounds into a convincing illusion of a performance (broadly) requires a bunch of "tricks" Otherwise the result is "uncanny" and unconvincing.

In this scenario, the actual speaker boxes play a role in "integrating" the sound. Especially if you look back to classic rock era, the monitor speakers were ether soffit mounted, or wooden boxes. Mixes were then checked in different environments, but I think the wooden box played a foremost role, as it was considered the best playback system.

It is inevitable that the monitors themselves are integral to the work product. In the end, the listener must hear sound waves created by a resonating object. In that case, the speakers are not intended to "disappear," they are fundamental in creating the effect the artists intend.

One of my pet theories about rock music is based on the aesthetic quality that it should be loud. It is possible to make recordings that sound loud when played back quietly. This is a tricky illusion.

One of the main carriers of such information is that objects generating a lot of sound energy are physical, and are usually recorded in a physical space. High sound pressure levels generate signature sonic characteristics in the way they interact with material objects. This sonic signature can be captured, and then played back at a lower level. The illusion works because we have an evolved auditory sense of when sound is loud, and when it is not. Quiet sounds just don't produce the same timbres as loud sounds.

(This is one reason that extreme dynamic range in a recording and playback system is not required to communicate the dynamics of a performance.)

Overall, this is a tough illusion to pull off. To help, the mixer can use the fact that the speaker itself is a resonating object, and by combining these sounds of different loudness characteristics into a resonating object, it helps create the illusion that the sounds actually coexisted at roughly the same SPL. This might not be the best approach in terms of a recording that translates well, but everyone works at the limit of possibility. Producers can get desperate.

It works like this:

Let's say you capture a drummer playing loud in a room. The resonating and reflecting objects generate the "loud" sound signature.

If you had a singer singing at a medium volume at the same time, in the same room, the drumset will drown out the singer. The singer does not generate enough SPL to make the walls reflect, to make the drums resonate enough, to capture the sound signature of the singer because drums are overpowering them.

But if you capture the "loud" drums, then mix in electronically (or digitally) the vocal, recorded separately, to make it as loud as the drums, the illusion that the voice is as loud as the drums is enhanced by effects that cause the voice signal to modulate the drum signal, in some way.

This can be done with signal processing, but it's hard, because are ears are very sensitive to the sound signatures of physical objects creating sound. It's hard to fake!

So as a "cheat" if you will, the mixer can rely to a degree on the fact that both the voice and the drums, if mixed to the same level, will actually modulate each other through the effects that are imparted to the physical object of the speaker.

The drums signal is encoded with sound level information that tells us approximately how loud it was. Likewise the vocals. But if these two signals resonate a speaker box, it creates a rich, complex sound signature that helps create the illusion that the voice was "right there with the drums," rattling the walls! In this example, the walls are the walls of the speaker cabinet, because turning up the whole playback system to rattle the actual walls of the room is um...a special case.

If you consider a physical acoustic instrument, it is a three dimensional object, that generates a very complex three dimensional sound in space. The full timbre of the instrument can't be captured with a single mic. (It's much easier, IMO, to get a realistic recording of a violin with more than one mic).

If you were standing in a room with a violin player, and you moved your head, you would experience a different sound, because the direct sound is coming from a different angle out of the violin. This information cannot be captured in a stereo (or mono) signal. This causes trouble for the illusion of the creating an actual three dimensional object in space. The illusion is unstable. Speakers that "disappear" are vulnerable to this collapse of the illusion.

On the other hand, if you have a "boxy" speaker, it actually is a physical, three-dimensional object, that exists right in the space you are listening. If you move around the room, you will hear a different timbre of sound, because the direct sound will be different. If the box is resonating, it will color the sound more from the side, versus a front listening position. Because of this, our mind can integrate the outputted signal in a way that does not require a narrow listening position, and is stable as the listener moves. (Because we know, instinctively, that when we move around a sound generating object, the sound will change. But our brain adjusts, so that it knows we are moving, and the speaker is standing still.)

Off the bat, I propose that this is a closer representation of the actual artistic work, if it was created in a studio, on speakers.

I haven't actually heard speakers like the open baffle designs of Linkwitz, those might be killer, I don't know. He does discuss on his website the problem of maintaing the image illusion, and claims that his bipolar speaker designs help stabalize the image.

But on speakers that have overly damped cabinets, music can tend to sound "uncanny" because the box is not completing the illusion. It sounds "fake".

On electrostatic speakers, which can generate almost a "holographic" sound image, floating in space, music created in a traditional studio environment can fall apart, with the instruments "floating" in random positions, sounding less related.

Floyd Tool in this lecture paints a picture of an ideal sound production system, as a whole, where the music producers rely on very neutral speakers to craft the product, and then the listeners listen on similar playback systems.


One can see that this might indeed be a kind of ideal, but at this point it seems only that, and cannot be relevant for legacy recordings.

One irony is that the point of view espoused by audiophile types, where speakers should represent acoustic events with some accuracy is an ever decreasing aspect of the music business. Where it's going is crazy, but that's another topic:)

From my understanding of the research Toole has done, listener preferences were the same across different genres of music. I find this surprising, but accept the results as presented.

But for the speakers that I am familiar with, those that come closer the "ideal" measured speakers produce a very unsatisfying listening experience, for myself. This paradox is currently the subject of some obsessive personal research:)
 

watchnerd

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#90
Thank you to everyone posting here, these are some very interesting insights and perspectives be expressed.

I just wanted to introduce a related concept that I haven't heard discussed

Siegfried Linkwitz (RIP) has some very definite ideas about what speakers should do. His ultimate designs are open baffle. (I've never heard such speakers, but really want to.) His website presents some very detailed explanations about sound presentation that are over my head, but I'm trying to chew through them. A lot of food for thought here...

http://www.linkwitzlab.com/speakers.htm

But part of his ideal is that the speakers should "disappear," leaving an experience of a kind of three-dimensional illusion for the listener, in the space. I am dubious.

He does seem to reflect that the best speakers should reproduce the illusion of a "live performance." I think this is a very narrow view, as soon as you step outside the realm of naturalistic recordings of acoustic instruments. (IMO, these type of recordings are easier to create and reproduce in general.)

I've never shared this perspective on what a playback experience should be, because to me recorded music is music. Most of my relationship with music is of the recorded type. Live performances are hit or miss, at best. (Well, records are too, but you can just turn off a bad record:)

Speakers that "image" well can produce an illusion of, for example, a violin in a room. In this case, if the speakers reach this "ideal" and disappear, the illusion is that a complex three-dimensional object, made of wood and metal, is actually the resonating object in the room, not the speakers.

This approach falls apart with most rock music or multitracked music. The problem is that the actual "resonating object" that is the medium upon which the artists construct their product are the monitor speakers in the control room!

One of the weird aspects of multitrack recording is the ability to superimpose instruments that naturally have very different SPL in a single recording. For example, you can combine a mandolin with a marshal guitar amp.

Then think about it: in a typical "pop" recording, we have a lead vocal floating on the top of instruments that generate far more sound energy!

To combine these disparate sounds into a convincing illusion of a performance (broadly) requires a bunch of "tricks" Otherwise the result is "uncanny" and unconvincing.

In this scenario, the actual speaker boxes play a role in "integrating" the sound. Especially if you look back to classic rock era, the monitor speakers were ether soffit mounted, or wooden boxes. Mixes were then checked in different environments, but I think the wooden box played a foremost role, as it was considered the best playback system.

It is inevitable that the monitors themselves are integral to the work product. In the end, the listener must hear sound waves created by a resonating object. In that case, the speakers are not intended to "disappear," they are fundamental in creating the effect the artists intend.

One of my pet theories about rock music is based on the aesthetic quality that it should be loud. It is possible to make recordings that sound loud when played back quietly. This is a tricky illusion.

One of the main carriers of such information is that objects generating a lot of sound energy are physical, and are usually recorded in a physical space. High sound pressure levels generate signature sonic characteristics in the way they interact with material objects. This sonic signature can be captured, and then played back at a lower level. The illusion works because we have an evolved auditory sense of when sound is loud, and when it is not. Quiet sounds just don't produce the same timbres as loud sounds.

(This is one reason that extreme dynamic range in a recording and playback system is not required to communicate the dynamics of a performance.)

Overall, this is a tough illusion to pull off. To help, the mixer can use the fact that the speaker itself is a resonating object, and by combining these sounds of different loudness characteristics into a resonating object, it helps create the illusion that the sounds actually coexisted at roughly the same SPL. This might not be the best approach in terms of a recording that translates well, but everyone works at the limit of possibility. Producers can get desperate.

It works like this:

Let's say you capture a drummer playing loud in a room. The resonating and reflecting objects generate the "loud" sound signature.

If you had a singer singing at a medium volume at the same time, in the same room, the drumset will drown out the singer. The singer does not generate enough SPL to make the walls reflect, to make the drums resonate enough, to capture the sound signature of the singer because drums are overpowering them.

But if you capture the "loud" drums, then mix in electronically (or digitally) the vocal, recorded separately, to make it as loud as the drums, the illusion that the voice is as loud as the drums is enhanced by effects that cause the voice signal to modulate the drum signal, in some way.

This can be done with signal processing, but it's hard, because are ears are very sensitive to the sound signatures of physical objects creating sound. It's hard to fake!

So as a "cheat" if you will, the mixer can rely to a degree on the fact that both the voice and the drums, if mixed to the same level, will actually modulate each other through the effects that are imparted to the physical object of the speaker.

The drums signal is encoded with sound level information that tells us approximately how loud it was. Likewise the vocals. But if these two signals resonate a speaker box, it creates a rich, complex sound signature that helps create the illusion that the voice was "right there with the drums," rattling the walls! In this example, the walls are the walls of the speaker cabinet, because turning up the whole playback system to rattle the actual walls of the room is um...a special case.

If you consider a physical acoustic instrument, it is a three dimensional object, that generates a very complex three dimensional sound in space. The full timbre of the instrument can't be captured with a single mic. (It's much easier, IMO, to get a realistic recording of a violin with more than one mic).

If you were standing in a room with a violin player, and you moved your head, you would experience a different sound, because the direct sound is coming from a different angle out of the violin. This information cannot be captured in a stereo (or mono) signal. This causes trouble for the illusion of the creating an actual three dimensional object in space. The illusion is unstable. Speakers that "disappear" are vulnerable to this collapse of the illusion.

On the other hand, if you have a "boxy" speaker, it actually is a physical, three-dimensional object, that exists right in the space you are listening. If you move around the room, you will hear a different timbre of sound, because the direct sound will be different. If the box is resonating, it will color the sound more from the side, versus a front listening position. Because of this, our mind can integrate the outputted signal in a way that does not require a narrow listening position, and is stable as the listener moves. (Because we know, instinctively, that when we move around a sound generating object, the sound will change. But our brain adjusts, so that it knows we are moving, and the speaker is standing still.)

Off the bat, I propose that this is a closer representation of the actual artistic work, if it was created in a studio, on speakers.
Most of the stuff you're describing is handled quite easily via standard tactics for level matching / peak limiting / compressors on a master buss...and has been since even before the advent of DSP.
 

RayDunzl

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#91
On electrostatic speakers, which can generate almost a "holographic" sound image, floating in space, music created in a traditional studio environment can fall apart, with the instruments "floating" in random positions, sounding less related.

That's news to me...
 

Stonetown

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#93
Thanks for sharing! That's a pretty funky.

Why is there a sheet on top of one of the speakers?
That is just a picture I took during constructing the front covers. You see the wood frame there also, checking that it fits before painting it black, and I just laid a piece of the black speaker fabric there to try to see how it will look like, and discovering at that moment I has to paint the wooden frame black :) Then on other picture you see when the fabric fronts are ready and in place, so we don't see the speaker elements any longer. The thing is, from beginning in the 80s, there were cell foam fronts but the foam has turned to dust long time ago :) Happened to all old speakers with foam plastic fronts from that time. Was not so durable material unfortunately. However I believe the fabric of this type I am using, with is a fine mesh, you can see a little through, is the best you can have in front of the speakers.

I am attaching some more pictures.
Cheers! /Per
 

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Cosmik

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#94
Siegfried Linkwitz (RIP) has some very definite ideas about what speakers should do. His ultimate designs are open baffle.
An interesting juxtaposition of statements, because if so, the conclusion would have to be that speakers should emit an inverted version of the signal out of the back, to bounce around the room and mix with the non-inverted version at the front. Even if one espouses the conventional view of audio as being only about phase-free frequency response magnitudes (I don't), such a system produces radical comb filtering all around the speaker (like listening to two speakers wired in anti-phase) and this is reflected off the walls, floor and ceiling to the listener. This is a radical modification of what I would think was the obvious requirements of a speaker!

I just don't get this argument about self-evident 'boxy' speaker sound. I listen to box speakers, and if they are reasonably designed and constructed, to me they disappear and image well.

My understanding of audio would be that you would mess with anti-phase at your peril: in order for your hearing to separate direct sound from the room, it needs the reflections to be facsimiles of the direct sound, particularly in regard of time domain asymmetry and 'envelope'. We know that the way to create 'surround sound from stereo' is to use anti-phase. It's unstable, and not artefact-free. The open baffle speaker is like adding a few random speakers behind the main speakers, emitting an antiphase version of the signal, like an ad hoc 'Superwide Stereo (TM)' system.

Maybe it sounds 'like really spacey, man' but I think this is arbitrary spaciousness (kind of) and not proper stereo imaging.
 
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Blumlein 88

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#95
That's news to me...
Me too, but I've only had direct extensive listening experience with 12 different electrostats. So maybe I just never noticed. My main daily speakers have been electrostats of one kind or another for only a bit over 30 years. I wouldn't want to rush to judgement.
 

Blumlein 88

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#96
Thank you to everyone posting here, these are some very interesting insights and perspectives be expressed.

I just wanted to introduce a related concept that I haven't heard discussed

Siegfried Linkwitz (RIP) has some very definite ideas about what speakers should do. His ultimate designs are open baffle. (I've never heard such speakers, but really want to.) His website presents some very detailed explanations about sound presentation that are over my head, but I'm trying to chew through them. A lot of food for thought here...

http://www.linkwitzlab.com/speakers.htm

But part of his ideal is that the speakers should "disappear," leaving an experience of a kind of three-dimensional illusion for the listener, in the space. I am dubious.

He does seem to reflect that the best speakers should reproduce the illusion of a "live performance." I think this is a very narrow view, as soon as you step outside the realm of naturalistic recordings of acoustic instruments. (IMO, these type of recordings are easier to create and reproduce in general.)

I've never shared this perspective on what a playback experience should be, because to me recorded music is music. Most of my relationship with music is of the recorded type. Live performances are hit or miss, at best. (Well, records are too, but you can just turn off a bad record:)

Speakers that "image" well can produce an illusion of, for example, a violin in a room. In this case, if the speakers reach this "ideal" and disappear, the illusion is that a complex three-dimensional object, made of wood and metal, is actually the resonating object in the room, not the speakers.

This approach falls apart with most rock music or multitracked music. The problem is that the actual "resonating object" that is the medium upon which the artists construct their product are the monitor speakers in the control room!

One of the weird aspects of multitrack recording is the ability to superimpose instruments that naturally have very different SPL in a single recording. For example, you can combine a mandolin with a marshal guitar amp.

Then think about it: in a typical "pop" recording, we have a lead vocal floating on the top of instruments that generate far more sound energy!

To combine these disparate sounds into a convincing illusion of a performance (broadly) requires a bunch of "tricks" Otherwise the result is "uncanny" and unconvincing.

In this scenario, the actual speaker boxes play a role in "integrating" the sound. Especially if you look back to classic rock era, the monitor speakers were ether soffit mounted, or wooden boxes. Mixes were then checked in different environments, but I think the wooden box played a foremost role, as it was considered the best playback system.

It is inevitable that the monitors themselves are integral to the work product. In the end, the listener must hear sound waves created by a resonating object. In that case, the speakers are not intended to "disappear," they are fundamental in creating the effect the artists intend.

One of my pet theories about rock music is based on the aesthetic quality that it should be loud. It is possible to make recordings that sound loud when played back quietly. This is a tricky illusion.

One of the main carriers of such information is that objects generating a lot of sound energy are physical, and are usually recorded in a physical space. High sound pressure levels generate signature sonic characteristics in the way they interact with material objects. This sonic signature can be captured, and then played back at a lower level. The illusion works because we have an evolved auditory sense of when sound is loud, and when it is not. Quiet sounds just don't produce the same timbres as loud sounds.

(This is one reason that extreme dynamic range in a recording and playback system is not required to communicate the dynamics of a performance.)

Overall, this is a tough illusion to pull off. To help, the mixer can use the fact that the speaker itself is a resonating object, and by combining these sounds of different loudness characteristics into a resonating object, it helps create the illusion that the sounds actually coexisted at roughly the same SPL. This might not be the best approach in terms of a recording that translates well, but everyone works at the limit of possibility. Producers can get desperate.

It works like this:

Let's say you capture a drummer playing loud in a room. The resonating and reflecting objects generate the "loud" sound signature.

If you had a singer singing at a medium volume at the same time, in the same room, the drumset will drown out the singer. The singer does not generate enough SPL to make the walls reflect, to make the drums resonate enough, to capture the sound signature of the singer because drums are overpowering them.

But if you capture the "loud" drums, then mix in electronically (or digitally) the vocal, recorded separately, to make it as loud as the drums, the illusion that the voice is as loud as the drums is enhanced by effects that cause the voice signal to modulate the drum signal, in some way.

This can be done with signal processing, but it's hard, because are ears are very sensitive to the sound signatures of physical objects creating sound. It's hard to fake!

So as a "cheat" if you will, the mixer can rely to a degree on the fact that both the voice and the drums, if mixed to the same level, will actually modulate each other through the effects that are imparted to the physical object of the speaker.

The drums signal is encoded with sound level information that tells us approximately how loud it was. Likewise the vocals. But if these two signals resonate a speaker box, it creates a rich, complex sound signature that helps create the illusion that the voice was "right there with the drums," rattling the walls! In this example, the walls are the walls of the speaker cabinet, because turning up the whole playback system to rattle the actual walls of the room is um...a special case.

If you consider a physical acoustic instrument, it is a three dimensional object, that generates a very complex three dimensional sound in space. The full timbre of the instrument can't be captured with a single mic. (It's much easier, IMO, to get a realistic recording of a violin with more than one mic).

If you were standing in a room with a violin player, and you moved your head, you would experience a different sound, because the direct sound is coming from a different angle out of the violin. This information cannot be captured in a stereo (or mono) signal. This causes trouble for the illusion of the creating an actual three dimensional object in space. The illusion is unstable. Speakers that "disappear" are vulnerable to this collapse of the illusion.

On the other hand, if you have a "boxy" speaker, it actually is a physical, three-dimensional object, that exists right in the space you are listening. If you move around the room, you will hear a different timbre of sound, because the direct sound will be different. If the box is resonating, it will color the sound more from the side, versus a front listening position. Because of this, our mind can integrate the outputted signal in a way that does not require a narrow listening position, and is stable as the listener moves. (Because we know, instinctively, that when we move around a sound generating object, the sound will change. But our brain adjusts, so that it knows we are moving, and the speaker is standing still.)

Off the bat, I propose that this is a closer representation of the actual artistic work, if it was created in a studio, on speakers.

I haven't actually heard speakers like the open baffle designs of Linkwitz, those might be killer, I don't know. He does discuss on his website the problem of maintaing the image illusion, and claims that his bipolar speaker designs help stabalize the image.

But on speakers that have overly damped cabinets, music can tend to sound "uncanny" because the box is not completing the illusion. It sounds "fake".

On electrostatic speakers, which can generate almost a "holographic" sound image, floating in space, music created in a traditional studio environment can fall apart, with the instruments "floating" in random positions, sounding less related.

Floyd Tool in this lecture paints a picture of an ideal sound production system, as a whole, where the music producers rely on very neutral speakers to craft the product, and then the listeners listen on similar playback systems.


One can see that this might indeed be a kind of ideal, but at this point it seems only that, and cannot be relevant for legacy recordings.

One irony is that the point of view espoused by audiophile types, where speakers should represent acoustic events with some accuracy is an ever decreasing aspect of the music business. Where it's going is crazy, but that's another topic:)

From my understanding of the research Toole has done, listener preferences were the same across different genres of music. I find this surprising, but accept the results as presented.

But for the speakers that I am familiar with, those that come closer the "ideal" measured speakers produce a very unsatisfying listening experience, for myself. This paradox is currently the subject of some obsessive personal research:)
What is your opinion of the "you are there" vs the "they are here" conundrum? Which is real fidelity? I've done some recording and can do recordings that are heavily one way or the other at will.
 

Blumlein 88

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#97
An interesting juxtaposition of statements, because if so, the conclusion would have to be that speakers should emit an inverted version of the signal out of the back, to bounce around the room and mix with the non-inverted version at the front. Even if one espouses the conventional view of audio as being only about phase-free frequency response magnitudes (I don't), such a system produces radical comb filtering all around the speaker (like listening to two speakers wired in anti-phase) and this is reflected off the walls, floor and ceiling to the listener. This is a radical modification of what I would think was the obvious requirements of a speaker!

I just don't get this argument about self-evident 'boxy' speaker sound. I listen to box speakers, and if they are reasonably designed and constructed, to me they disappear and image well.

My understanding of audio would be that you would mess with anti-phase at your peril: in order for your hearing to separate direct sound from the room, it needs the reflections to be facsimiles of the direct sound, particularly in regard of time domain asymmetry and 'envelope'. We know that the way to create 'surround sound from stereo' is to use anti-phase. It's unstable, and not artefact-free. The open baffle speaker is like adding a few random speakers behind the main speakers, emitting an antiphase version of the signal, like an ad hoc 'Superwide Stereo (TM)' system.

Maybe it sounds 'like really spacey, man' but I think this is arbitrary spaciousness (kind of) and not proper stereo imaging.
Once the rear wave bounces off a wall and reflects forward it isn't reverse phase any more. It will create filtering like effects. So will non-inverted rear reflection. Like the old Mirage speakers which were bipolar.

Maybe dipoles do a better job delineating to our hearing just what is the room and what isn't letting us hear thru to the real signal with less difficulty. Harman experiments be damned!
 

Cosmik

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#98
Once the rear wave bounces off a wall and reflects forward it isn't reverse phase any more.
I thought we had already debunked that myth?
https://blog.soton.ac.uk/soundwaves/wave-interaction/2-reflection/

"Reflection of a sound wave at a hard wall
At the wall there can be no particle motion, but the pressure can, and will, vary. In order for the particle velocity to be zero at the wall the pressure gradient must be zero. The reflected wave pulse then travels from right to left, with the same speed and amplitude as the incident wave, but this time with the same polarity (the positive pressure pulse is reflected as a postive pulse)."

To the pure frequency domain person it doesn't matter - a sine wave looks the same whether it is inverted or not. But for the time domain-cognisant person, an asymmetric impulse is different when it is inverted.
 
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#99
What is your opinion of the "you are there" vs the "they are here" conundrum? Which is real fidelity? I've done some recording and can do recordings that are heavily one way or the other at will.
Can you describe this distinction a little more? My first interpretation is that what I describe as a preference, that I have resonating objects in the room with me, that are the “sound sources” is the “they are here” paradigm?

I think what I’m talking about inevitably relates to the approach the producers have taken to their product.

If they are dedicated to crafting a three-dimensional “illusion” of another space, with the resonating objects represented within it, then a system that really focuses on reproducing this effect could really shine. It’s easier to do with simpler recordings, of acoustic objects, because stereo mics really will capture a signal than can provide a remarkable illusion of the recorded object in space, floating between the speakers. When working on a recording, I find it easier to conceptualize the sound of a violin. I know what they sound like, and can be sensitive to whether the changes I make are preserving the image.

With a rock recording, let’s say Pink Floyd DSOTM, they didn’t have a real world reference, they created themselves. In such a case, it is unclear what it would mean to try and represent a convincing “illusion” of the original performance, as it only ever existed as an acoustic event as it was played on monitors. That means the complete sound experience is not encoded in the stereo signal.

My argument is that the best way to represent the experience of DSOTM is to use speakers that are similar to the monitors and playback systems of the day. In this sense, you bring the experience “in to the room with you.” It’s not an illusion, it’s an original experience.

One of the problems with trying to craft signals that take advantage of this weird ability to represent 3D space from a pair of 2D signals, is that it sensitive to a relatively high performance playback system, with good speakers, in a relatively symmetrical room. Since this is the distinct minority of playback systems, and ever decreasing, it limits the effectiveness of your expression to rely on it.

The Beatles didn’t rely on this, at all. They used mono mixes. The hard panned stereo versions done by George Martin after the fact sound ridiculous on a good stereo playback system. But in most everyday situations the Beatles sound fantastic.
 
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That's news to me...
What kind of music do you like to listen to? I notice the effect I'm talking about on something like a Queen song like "Don't Stop Me Now" as an example. If I sit in front of speakers that image well, it sounds quite strange.

The voice is in the middle, the piano is close mic'd with a hard stereo pan. The drums are these kind of thuddy, almost weak sound. It doesn't sound integrated at all. But if I'm listening further away, not in the sweet spot, and I've got in on some reasonable speakers, nothing spectacular, it comes together quite wonderfully. The ultimate image requires the speakers, the room, and the signal presented by the drivers to all come together.
 
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