SO ... HOW do we measure soundstage???

[goat76]

The in-room reflections of the direct sound are not detrimental as long as they don't arrive too early, but ime it is the reflections of the reverberation tails that can really make the difference if they are presented effectively.

For instance, I've heard the spatial presentation transition from "I'm in a normal room and the soundstage extends a few feet behind the speakers" to "I'm in a huge space and the soundstage extends to about as far away as the musicians would have actually been" when the playback room's package of spatial cues gave way to the recording's package of spatial cues due to a change in speaker placement. No way this perceptual difference could arise from a slight modification of the playback room's signature; the only information available that could have conveyed enormous depth and spaciousness was the reverberation tails on the recording, and the speaker placement change resulted in the venue signature on the recording becoming perceptually dominant.

Yes, but most of that spatial information comes with the direct sound of accurately positioned loudspeakers in an acoustically treated and well-behaved listening room. The late reflections that build up the diffuse sound in the listening room, which in turn adds to the sensation of envelopment, is just a "soup" of everything in the recording, both the recorded direct sounds and the recorded reverb tails without any distinction, but that doesn't matter much as it all will add to the sensation of envelopment anyway (as long as it is delayed enough vs the direct sound and is treated as a separate sound to our sense of hearing).

 

[Justdafactsmaam]

Your statement is very easy to falsify just by giving you a sound example of an old stereo recording, you know one of those old "ping-pong" stereo recordings where everything in the mix was either hard-panned to the left or the right speaker.

In the following file of the original recording, it's easy the hear that all the sounds come from the exact point of each loudspeaker. This is how the recording sounds without any effect added to it.

How does that falsify anything?

Original track (30 sec): https://www.dropbox.com/scl/fi/7i6a...-sec.wav?rlkey=duoor29q01zwc51f0lfol1vh0&dl=0


This is the same recording but with the BACCH filter applied (specified for a 30-degree listening triangle).

“Specified?” By whom? Where? Please cite the industry standard used by all recording engineers for speaker/room/listener setup.

I'm sure you can easily hear that the localization of the channels is now much more diffuse and no longer sounds as distinctly coming from the position of the two loudspeakers.

You are wrong about it sounding diffuse.

As for the image not coming distinctly from the speaker. That’s a bad thing?! You think that every recording engineer and recording artist did hard pans because they thought “I am so glad that I am limited by crosstalk to a soundstage that stops at the speaker! Thank god I can’t extend the imaging beyond the speakers! The speaker is exactly where I wanted that hard pan to land!”

“This is of course less accurate to the source, “

If you consider the source to be the recording that is plainly wrong. You can not add to the content of the source material and make it more accurate to your he source material.
If you consider the source material the original acoustic event then clearly the limitations crosstalk imposed on the playback will always be less true to the original event

and this will affect all regularly mixed 2-channel recordings in the same inaccurate way, even the ones you may subjectively like this effect on.

Track with uBACCH for a 30-degree listening triangle (30 sec): https://www.dropbox.com/scl/fi/fajd...-sec.wav?rlkey=0ia8tt7qk0mvxf66wxuqwkoww&dl=0

.

Please give us a specific definition of a “regularly mixed 2 channel recording” until that is clearly defined with measurable parameters you can’t use it as a premise for your argument

 

[Justdafactsmaam]

Sure, everything can be done good or badly, but the problem of listening not with the own ears has little to with that.
I made some fun recordings with in ear microphones. The result was amazing, it was crazy how realistic and even holographic that was. You will hardly get anything near with some dummy head.
I wondered whether my ears are symmetric and switched channels in the replay. The whole room collapsed and everything I heard played at the back of my head. Left me quite surprised.
It is just an individual thing.

No doubt at this point there is no such thing as a perfect recording. But that is true for all techniques.

Watch out though. No reason to think further DSP can’t convert standard binaural recordings to ones customized for personal head transfer functions

 

[goat76]

I see only one way of doing so by means of headphones and binauralization.
There crosstalk can be switched off or attenuated at will. And one can use a reverberation file with as much (or little) reverberation as is preferred.
Makes a great desktop system ;-)

I think it can sound pretty convincing when adding a delayed reverb to the surround channels to an otherwise normal stereo recording, making it a 4-channel mix. I made one such mix out of some free stems of Beethoven's 5th Symphony I found on a website, I don't think anything more than that is needed to make it sound more real.

 

[Blumlein 88]

I know this is not news, but a good bit of info from another thread on ASR. Shows the FR difference in a center speaker vs stereo.

https://www.audiosciencereview.com/forum/index.php?attachments/1709771795636-png.354644/

 

[olieb]

I think it can sound pretty convincing when adding a delayed reverb to the surround channels to an otherwise normal stereo recording, making it a 4-channel mix. I made one such mix out of some free stems of Beethoven's 5th Symphony I found on a website, I don't think anything more than that is needed to make it sound more real.

I have a Realiser and can compare stereo mix to Atmos mix. The difference is underwhelming in most cases. [EDIT: that is with the provided university room BRIR with KEMAR, not my own ears sadly] To me the sound actually is better when recreating the binauralization in stereo on my laptop and reduce crosstalk (-12dB or -20dB).
[And use the center channel for convolving instead of left and right: better FR]
If only I could get head tracking on the computer. ;-)

 

[Duke]

@goat76, imagine you wanted to process a regular stereo recording so that it sounded like a binaural recording as much as possible, and to do so over loudspeakers rather than through headphones. You'd have to figure out how to cancel the crosstalk, and you'd want to compensate for the head-related transfer function, all without introducing coloration or unnatural artifacts. Play-back of the recording still wouldn't have the exact same perspective as a recording made with the in-ear microphones used for true binaural recordings, but you'd be closer. Whether or not "closer" was a worthwhile improvement in spatial realism would probably depend on the specifics, but it certainly could be a worthwhile improvement in spatial realism.

My understanding is that the BACCH-SP processing seeks to approximate the binaural experience using normal stereo recordings played back through a stereo pair of loudspeakers by addressing the discrepancies between the signals normal stereo through loudspeakers presents to each ear canal, and the signals binaural stereo through in-ears presents to each ear canal. I understand that you think this approach is flawed, and I'm unlikely to convince you otherwise, but wanted to suggest you look at it from the angle of being an approximation of binaural.

 

[Keith_W]

I wonder if asking listeners to mark a card like this would help.

 

[Duke]

Yes, but most of that spatial information comes with the direct sound of accurately positioned loudspeakers in an acoustically treated and well-behaved listening room.

Agreed that by far most of the sound image localization cues come from the direct sound. But I do not think that is true of the ambience/spaciousness/envelopment cues, assuming the room isn't overdamped.

The late reflections that build up the diffuse sound in the listening room, which in turn adds to the sensation of envelopment, is just a "soup" of everything in the recording, both the recorded direct sounds and the recorded reverb tails without any distinction, but that doesn't matter much as it all will add to the sensation of envelopment anyway (as long as it is delayed enough vs the direct sound and is treated as a separate sound to our sense of hearing).

My understanding is that the ear/brain system can track the reverberation tails (even well down into the noise floor) as long as their overtone structures are sufficiently intact. I wouldn't describe that as the perceptual equivalent of "soup".

On the other hand, ime an overabundance of early in-room reflections muddies ("soupifies"?) the presentation in both sound quality and spatial quality, hence my advocacy for minimizing the early reflections while preserving the later ones as much as possible.

 

[goat76]

How does that falsify anything?

Because we know exactly where all the sounds are in the mix in such a recording, they should neither be coming from a place outside nor inside the loudspeakers as they are fairly dry recorded sounds. With the BACCH filter they sound less "stuck" to the speakers which we know they should for this recording.

“Specified?” By whom? Where? Please cite the industry standard used by all recording engineers for speaker/room/listener setup.

Specified for my speaker setup. So if someone else wants to demo the files in their system they can use a 30-degree listening triangle as a starting point, and then move their listening position front or back until they find where it sounds the best in their room and with their speakers. It's not more complicated than that.

You are wrong about it sounding diffuse.

Let's see what other people think.

As for the image not coming distinctly from the speaker. That’s a bad thing?! You think that every recording engineer and recording artist did hard pans because they thought “I am so glad that I am limited by crosstalk to a soundstage that stops at the speaker! Thank god I can’t extend the imaging beyond the speakers! The speaker is exactly where I wanted that hard pan to land!”

The example has nothing to do with preference, it's a fact that this mix has only hard-panned sounds and they should just be heard from the exact positions of the loudspeakers, not outside or inside the speakers, and not have a diffuse glare to them in any way at all as they are fairly dry recorded.

“This is of course less accurate to the source, “

If you consider the source to be the recording that is plainly wrong. You can not add to the content of the source material and make it more accurate to your he source material.
If you consider the source material the original acoustic event then clearly the limitations crosstalk imposed on the playback will always be less true to the original event

Just listen to the two recordings and hear which one has the recorded sounds more attached and "locked" to each speaker, the original file or the one with the BACCH filter applied.
First hint: The recording that sounds dryer and has a more pinpoint position of the sounds is in this case the more accurate playback.
Second hint: If you concentrate on the sound from just one of the loudspeakers, which recording sounds closer to the sound if just one speaker were just playing that channel in mono?

Please give us a specific definition of a “regularly mixed 2 channel recording” until that is clearly defined with measurable parameters you can’t use it as a premise for your argument

As well as using the word "regular" I could have also said "common".
A regular or common 2-channel mix is a mix done using regular or common loudspeakers in a normal 2-channel setup without the use of crosstalk cancellation during the mixing stage. A mix where every mixing decision was made while hearing the natural crosstalk that occurs between the speakers, which in turn affected the way the mixing engineer decided how everything should be panned to sound as intended on other regular or common loudspeakers.

 

[Justdafactsmaam]

Because we know exactly where all the sounds are in the mix in such a recording,

No you don’t. There is no standard setup for studio monitors and control rooms. So you don’t know

they should neither be coming from a place outside nor inside the loudspeakers as they are fairly dry recorded sounds. With the BACCH filter they sound less "stuck" to the speakers which we know they should for this recording.

“Should?” By what authority do you get to dictate “should?”

Can you cite any artist or recording engineer that has explicitly stated their goal was to stick certain instruments at the speaker locations?

Can you cite any recording engineers or artists in classical music who state their goal was to miniaturize the soundstage, the size of the orchestra, the size of the instruments and to avoid anything that comes closer to the real size, depth, width, height, instrument localization and defined representation of hall reverb?

Because that is exactly the difference of most classical recordings with the speaker cross talk and with the crosstalk cancelation

Let's see what other people think.

I have.

The example has nothing to do with preference, it's a fact that this mix has only hard-panned sounds and they should just be heard from the exact positions of the loudspeakers, not outside or inside the speakers, and not have a diffuse glare to them in any way at all as they are fairly dry recorded.

Please show me citations of recording engineers that explicitly state hard pans sound ideal when localized on the speakers. “That’s what I wanted and that’s what I would have done even if I had the option localize the image outside, behind and/or on front of the speaker”

Just listen to the two recordings and hear which one has the recorded sounds more attached and "locked" to each speaker, the original file or the one with the BACCH filter applied.

Dude, speaking for myself, I ****ing hated all hard pans BECAUSE they were glued to the speaker! They were the ultimate betrayal of any remote illusion of stereo imaging and illusion of transportation to a concert hall or any acoustic space. BACCH was a miracle cure for that disease.

And frankly if that actually was the goal of a recording engineer (which I highly doubt in most cases) I am fixing his or her terrible judgement.

But I suspect (yes I am speculating) that in most cases the wish was to extend the image well beyond the speaker and the hard pan was the crappy compromise they had to settle for.

In the case of classical music this should be self evident for reasons stated above. Find me a classical recording engineer who says “my goal is to make a real orchestra sound like a Lilliputian orchestra that fits in a 6 to 10 foot box between someone’s speakers, eliminate the sound of the original orchestra hall and replace it with the listening room reverb”

Which classical music recording engineer say’s that?

As well as using the word "regular" I could have also said "common".

Which is just as meaningless and objectively undefined.

 

[Thomas_A]

No such a thing as “normal” there are books written on recording techniques for classical recording. But the vast majority of these stereo recordings manage to encode a substantial amount of spatial information.

Ideal recording would be a custom binaural recording

And that spatial information is heard over stereo as well, if you don't mess up early reflections and take care of room dips/peaks. If you take my Youtube example again, what is the spatial information? Answer: It is in the mixers hand - reverb an position. So there is no "van". If you take a concert hall, there are many microphones, above, in front of the orchestra, and several close-up microphones. Spatial information is captured and everything is mixed to sound good over speakers "at home". It is not mixed to sound as that of position chair 61 in the concert hall. What about chair 235?

 

[Justdafactsmaam]

And that spatial information is heard over stereo as well, if you don't mess up early reflections and take care of room dips/peaks.

It’s heard. Not nearly as well.

If you take my Youtube example again, what is the spatial information? Answer: It is in the mixers hand - reverb a position. So there is no "van". If you take a concert hall, there are many microphones, above, in front of the orchestra, and several close-up microphones. Spatial information is captured and everything is mixed to sound good over speakers "at home". It is not mixed to sound as that of position chair 61 in the concert hall. What about chair 235?

Yeah, I think this is an overly broad and highly presumptuous assertion. If you look at how many of the golden age classical recordings and audiophile classical recordings were made they were invariably minimalist recordings with minimalist mixes done with very specific goals of creating a life like recreation of the event from a fairly specific perspective.

That spatial information in those recordings can create a remarkably lifelike experience IF the spatial cues are not corrupted by room reflections and even more so crosstalk.

Multi microphone recordings are certainly more easily manipulated in the mix but the results are pretty much the same when it comes to the effects of playback. Crosstalk and room reflections reduce the size of the soundstage down to the distance between the speakers and reduces everything in that sound stage as well as homogenizing it.

If that was the intention of the recording engineer then I veto his intentions for what is for me a vastly superior playback experience.

If some people like miniature orchestras in their rooms so be it. I prefer something closer to a big as life transportation to the concert hall experience

 

[Suono]

That spatial information in those recordings can create a remarkably lifelike experience IF the spatial cues are not corrupted by room reflections and even more so crosstalk

absolutely not, the recordings cited are masterpieces precisely because they were not manipulated by SW. I repeat, these masterpieces should be listened to in a set up with a balance between direct and reverberated sound. then you will have a sense of the breath of the room where it was recorded.

 

[Justdafactsmaam]

absolutely not, the recordings cited are masterpieces precisely because they were not manipulated by SW. I repeat, these masterpieces should be listened to in a set up with a balance between direct and reverberated sound. then you will have a sense of the breath of the room where it was recorded.

Based on your experience with highly directional low distortion speakers in a very dead room using the BACCH crosstalk cancelation SP?

You’ve done direct comparisons and found this to give a smaller, less life like soundstage with less clarity in the imaging of the instruments, smaller apparent size and less clarity in the hall reverberation?

If so do tell. What sort of XTC and impulse response measurements were you getting from the BACCH? Can you post an image?

 

[Suono]

Beyond measuring, take the speakers into the garden and listen to see if you can feel the ambience of the recording location

 

[Suono]

reverberation is used to recreate spatiality…

 

[Sokel]

The easy way I used for setting up soundstage so it doesn't have holes and is nice and symmetrical (not in my current rig,I only use this test if I want to see other problems now) is by using one of the various arc test signals,close my eyes and just point to the two outer ones or the highest one of the signal chain with my hands.
Then open my eyes and see where I point.
It's easy and fun!

 

[olieb]

reverberation is used to recreate spatiality…

I don't see anyone thinks otherwise, but there are two kinds of reverberation:
• the reverberation from the recording (room), albeit typically recordings have only little reverberation compared to "being there".
• the reverberation from the listening room, which is more or less the wrong kind of reverberation for the signal.

 

[Suono]

I don't see anyone thinks otherwise, but there are two kinds of reverberation:
• the reverberation from the recording (room), albeit typically recordings have only little reverberation compared to "being there".
• the reverberation from the listening room, which is more or less the wrong kind of reverberation for the signal.

I confirm and reiterate, the reverberation mentioned in the book is that of our room, the spatiality obtained is that of the room where the event is recorded.