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

guy48065

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Anyways my point was that I don't believe reflected sound in the listening environment helps create the soundstage. It can only confuse it.
 
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On a pair of tri-amped speakers, by adjusting the time delay to the tweeters in micro-second increments, I can manipulate how wide or near together the stereo pair of speakers seem to be positioned.
 

goat76

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Anyways my point was that I don't believe reflected sound in the listening environment helps create the soundstage. It can only confuse it.

That's right. What the listening environment "sees" when it comes to sound sources is just the two loudspeakers (if we are talking 2-channel audio) in the room, just two "sound generators" that trigger the reflections in the room treated as just two separate sounds without any clue what's supposed to be separate sounds in the stereo image. The higher the ratio of reflections from the listening environment vs the direct sound from the loudspeakers, the less precise the stereo imaging will be.

But with that said, and based on how bad a pair of loudspeakers in a stereo configuration sounds in an anechoic chamber (according to people who have heard that), we want some of the reflections from our listening environment to at least hide the simplicity of just using two sound sources reproducing the complex sound image of a recorded space. Most of us will probably also want some envelopment in the sound to perceive it as more convincing, so if the recordings don't have some "out-of-phase stereo tricks" going on, some late reflections from the listening environment will be needed to do that.

Strong early side wall reflections that artificially widen the stereo image will be hurtful to the pinpoint accuracy of the stereo imaging. The pinpoint accuracy can only come with the direct sound from the two accurately positioned loudspeakers, which together will recreate a unified stereo image in the listener's mind. The best way to know that the two loudspeakers are accurately positioned, according to each other and the listening position, is that the center phantom image will sound almost as distinct and focused-sounding as if the sound was truly coming from a third physical loudspeaker as a center channel. If the center phantom image sounds "washed out", the two loudspeakers are probably positioned too wide and that will affect the accuracy of the whole stereo image. The phantom image can be used as the "compass" or the "anchor" to get the stereo image as accurate as possible, and everything down to the finer details in the stereo image should fall into the right places when this is done.

If everything sounds like it has a wide soundstage, it's probably an indication that things are not very accurate with the setup of the sound system.
If the variety is large from recording to recording, it can likely be an indication that the setup is close to being accurately set up. :)
 

audiofooled

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I watched this presentation by J_J. He briefly talks about imaging and soundstage measurement. Nothing not already discussed in this thread. If I had marked it I would give the part where it is covered. It is pretty early, I think in the first 15 minutes.


If you have another hour or so, I'd also like to propose this earlier presentation by J_J:


What happens when you put your head in a sound field is another problem. Valuable information to someone who needs to know about more problems :)
 

guy48065

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...
But with that said, and based on how bad a pair of loudspeakers in a stereo configuration sounds in an anechoic chamber (according to people who have heard that), we want some of the reflections from our listening environment to at least hide the simplicity of just using two sound sources reproducing the complex sound image of a recorded space. Most of us will probably also want some envelopment in the sound to perceive it as more convincing, ...
My current home that I've lived in 30 years doesn't leave me many options for a decent listening environment but my previous home had a large empty basement where I built a budget Live End-Dead End audio room. It was wonderful.

My frustration with not having a decent room contributed to me "shelving" my audiophile pursuits for 30 years.
 

goat76

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My current home that I've lived in 30 years doesn't leave me many options for a decent listening environment but my previous home had a large empty basement where I built a budget Live End-Dead End audio room. It was wonderful.

My frustration with not having a decent room contributed to me "shelving" my audiophile pursuits for 30 years.

It's a luxury to have a dedicated listening room, but it's possible to get a decent sound in a normal living room without too much acoustic treatment just by shrinking the listening triangle for a higher ratio of direct sound. Maybe you can achieve that just by rearranging things in the room to get a tighter listening triangle. With a free-standing listening position and the speakers placed as far away as possible from the walls, you can probably get the early reflections down to around -20dB under the direct sound depending on the size of the room.
 

Purité Audio

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My current home that I've lived in 30 years doesn't leave me many options for a decent listening environment but my previous home had a large empty basement where I built a budget Live End-Dead End audio room. It was wonderful.

My frustration with not having a decent room contributed to me "shelving" my audiophile pursuits for 30 years.
Rarely perfect but it is easier now to achieve a decent result, cardioid response and speakers whose off-axis mirrors their on, adjustable bass output , built in peq, sophisticated tone controls all help to achieve a really fine sound in untreated domestic rooms.
Keith
 

Justdafactsmaam

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"Dispersion"..."directivity"..."ratio of direct to reflected sound"...
Taking these oft-repeated assumptions a little farther leads me to a simple question. (Surely this has been explored...)

Can a stereo system create a soundstage in an anechoic chamber?
I’m sure it can
 

Justdafactsmaam

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But with that said, and based on how bad a pair of loudspeakers in a stereo configuration sounds in an anechoic chamber (according to people who have heard that), we want some of the reflections from our listening environment to at least hide the simplicity of just using two sound sources reproducing the complex sound image of a recorded space.
Where are there any first hand accounts of anyone listening to a well set up stereo system in an anechoic chamber? I have never seen any such first hand account. And if there were, given expectation bias how reliable would it be?
 

Thomas_A

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I’m sure it can
If we are talking stereo anechoic setups they will certainly reproduce the "soundstage" of the recording but at the same time, you
1) will not get envelope and "normal" directional cues, which is part of what the brain expects from room acoustics
(- you can instead use multichannel to get the envelope, which is even better)
2) will exaggerate the stereo errors to its maximum
 

Justdafactsmaam

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If we are talking stereo anechoic setups they will certainly reproduce the "soundstage" of the recording but at the same time, you
1) will not get envelope and "normal" directional cues, which is part of what the brain expects from room acoustics
The brain has no expectations. It processes what the ears and eyes gives it. You will get the directional cues that are on the recording without room reflections. The listening room reflections give us conflicting cues to those on the recording which compromises the illusion of imaging.

(- you can instead use multichannel to get the envelope, which is even better)
2) will exaggerate the stereo errors to its maximum
What are the “stereo errors” and how are they exaggerated by less room reflections?
 

Thomas_A

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The brain has no expectations. It processes what the ears and eyes gives it. You will get the directional cues that are on the recording without room reflections. The listening room reflections give us conflicting cues to those on the recording which compromises the illusion of imaging.


What are the “stereo errors” and how are they exaggerated by less room reflections?
See Toole and Shirley et al, it has been discussed at many occasions.


With respect to directional cues; you have the cues on the recording and then cues what the speakers give you. If you have the lounge model (your room is an opening to the event) you have no reason to not include the room reflections. If you want to be at the event - use multichannel.
 

goat76

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Where are there any first hand accounts of anyone listening to a well set up stereo system in an anechoic chamber? I have never seen any such first hand account. And if there were, given expectation bias how reliable would it be?

I have no controlled tests I can refer to and have never had the opportunity to be in such a room myself, even though there does exist an anechoic chamber at the school where I live. I have only heard from people who have had the opportunity to listen to speakers in an anechoic chamber, and according to them the experience was similar to listening to headphones, the soundstage collapsed and appeared to be located inside the listener's head. I don't know about your preferences, but I prefer the soundstage that can be had listening to loudspeakers over listening to headphones.
 

Justdafactsmaam

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See Toole and Shirley et al, it has been discussed at many occasions.
I’ve seen Toole. I don’t think he is right about early reflections


With respect to directional cues; you have the cues on the recording and then cues what the speakers give you.
The speakers give you the cues on the recording. And due to cross talk they give away their own spatial positions. Which is a bad thing.

you have the lounge model (your room is an opening to the event) you have no reason to not include the room reflections. If you want to be at the event - use multichannel.
Sure you do. Room reflections conflict with spatial cues on the recording.

Consider a symphony recording. Do you want a miniature symphony playing in your room? That’s what you get with room reflections. Or do you want to be transported to a concert hall? That’s what you get when you lose room reflections and cross talk. If the cues are present on the recording of course. Either way you get what’s on the recording without the room reflections confusing it.
 

Justdafactsmaam

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I have no controlled tests I can refer to and have never had the opportunity to be in such a room myself, even though there does exist an anechoic chamber at the school where I live. I have only heard from people who have had the opportunity to listen to speakers in an anechoic chamber, and according to them the experience was similar to listening to headphones, the soundstage collapsed and appeared to be located inside the listener's head. I don't know about your preferences, but I prefer the soundstage that can be had listening to loudspeakers over listening to headphones.
Call me skeptical. Having lived with the BACCH SP and about as dead a room as one can get in a home environment I will tell you first hand the opposite happens and you get a remarkably life like soundstage and imaging with the recordings that have the spatial cues to provide that experience. I doubt an anechoic chamber would do anything other than slightly improve the illusion
 

Thomas_A

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I’ve seen Toole. I don’t think he is right about early reflections


The speakers give you the cues on the recording. And due to cross talk they give away their own spatial positions. Which is a bad thing.


Sure you do. Room reflections conflict with spatial cues on the recording.

Consider a symphony recording. Do you want a miniature symphony playing in your room? That’s what you get with room reflections. Or do you want to be transported to a concert hall? That’s what you get when you lose room reflections and cross talk. If the cues are present on the recording of course. Either way you get what’s on the recording without the room reflections confusing it.
It all depends what model you want. Do you want to be transferred to the event? Use multi-channel. Stereo is no solution for that. Do you want your room to be a lounge with an opening to the event. Use stereo or rather three-channel. And symphony orchestra should not be in your room, it should be far away from the room boundary. Which needs tricks to remove cues from distance detection of your speakers.
 

ahofer

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It all depends what model you want. Do you want to be transferred to the event? Use multi-channel. Stereo is no solution for that. Do you want your room to be a lounge with an opening to the event. Use stereo or rather three-channel. And symphony orchestra should not be in your room, it should be far away from the room boundary. Which needs tricks to remove cues from distance detection of your speakers.
Here we enter the circle of confusion with recordings. An orchestra or chamber group is typically recorded not just with a single pair or “Decca Tree” of mics (apologies Telarc) but with multiple spot mics. Concerti are worse, because if you use a single suspension tree, sometimes the featured instrument just gets buried in the recording. And in either case, the mics are at the front of the hall, not back where the seats are. So you aren’t really getting a reproduction of the audience position, you are getting something closer to a conductor’s position with a solo instrument emphasis. So in that case, a little room reflection will add back hall ambience that would have been there in the live event.

With all that said, I really like the Telarc recordings. I had been under the impression they simply used the one mic tree, but in the thread linked above there is a claim that some rear hall mics were used to ‘add back’ ambience.

I used to help my old Physics professor/House Master make piano and chamber music recordings in college. He used a simple stereo pair with one of the first digital recorders in our large and live dining hall. They sounded excellent, although there was a lot of the room in them.
 

Justdafactsmaam

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It all depends what model you want. Do you want to be transferred to the event?
As much as possible
Use multi-channel. Stereo is no solution for that.
Multichannel doesn’t cut it unless it’s a dedicated original multichannel recording. The BACCH SP, really low distortion highly directional speakers and dead as a door nail listening room is doing it quite convincingly

Do you want your room to be a lounge with an opening to the event.
No

Use stereo or rather three-channel. And symphony orchestra should not be in your room, it should be far away from the room boundary. Which needs tricks to remove cues from distance detection of your speakers.
with a reflective listening room the symphony ain’t getting out of the room boundaries
 

Justdafactsmaam

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Here we enter the circle of confusion with recordings. An orchestra or chamber group is typically recorded not just with a single pair or “Decca Tree” of mics (apologies Telarc) but with multiple spot mics. Concerti are worse, because if you use a single suspension tree, sometimes the featured instrument just gets buried in the recording. And in either case, the mics are at the front of the hall, not back where the seats are. So you aren’t really getting a reproduction of the audience position, you are getting something closer to a conductor’s position with a solo instrument emphasis. So in that case, a little room reflection will add back hall ambience that would have been there in the live event.

With all that said, I really like the Telarc recordings. I had been under the impression they simply used the one mic tree, but in the thread linked above there is a claim that some rear hall mics were used to ‘add back’ ambience.
Depends on the mix. Many modern multi miked orchestral recordings do an amazing job of imaging, sound staging and capturing spatial cues
 
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