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Controlled vs wide dispersion in a normal living room environment..
Controlled vs wide dispersion in a normal living room environment..
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Old Today, 12:01 PM   #721
Pano is offline Pano  United States
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Controlled vs wide dispersion in a normal living room environment..
Quote:
Originally Posted by soundbloke View Post
The deleterious effects of conventional stereo reproduction are immediately obvious to anyone who has heard stereo reproduced in an anechoic environment.
Well perhaps not immediately. Having often heard stereo reproduction in anechoic and hypoechoic environments, I didn't notice any deleterious effects for stereo. What would those be?
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Originally Posted by soundbloke View Post
Again, Apparent Source Width is a perception of an acoustic source in a first listening environment. It is not a measure of the image properties of a recorded source reproduced over one or more loudspeakers in a second listening environment.
Source width can be altered with phase tricks. That can be done in the recording or in playback, sometimes by accident. Gaming and VR often use tricks like that.
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Old Today, 05:03 PM   #722
gedlee is offline gedlee  United States
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Quote:
Originally Posted by soundbloke View Post
Again, Apparent Source Width is a perception of an acoustic source in a first listening environment. It is not a measure of the image properties of a recorded source reproduced over one or more loudspeakers in a second listening environment.
This is simply not true. Toole often used this term applied to loudspeaker reproduction.
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Early reflections of loudspeakers are better described as enhancing our perception of the loudspeakers (and their images) rather than the material they are reproducing. In recent decades, significant attention has been directed at minimising the effects of diffraction around loudspeakers for much the same reason that early reflections can also be deleterious.

Boosting lateral low frequency information in stereo channels can also significantly enhance the perception of envelopment without the need for extra speakers.
It bothers me that you keep describing the LF information in stereo channels but then you finish with implications of the whole spectrum. This simply isn't the case. I don't worry too much about the LF stereo problems in real small rooms because these rooms act modally and reflections per see are not relevant - they happen in a time frame too short for our hearing to even detect them. The theoretical comb filtering of central images simply won't occur perceptually in a small room at LFs simply because the ear will integrate the sound from many many reflections thus nulling out the comb filter. Now at higher frequencies where the ear can analyze a reflection and the direct field as separate events there will be a comb filter or more specifically an image shift and coloration. But we absolutely must separate perception in a small room between LFs and HFs as the two things act completely different. In large spaces they are not separate and we can combine the two regions into a single perception.

I too have heard stereo in an anechoic chamber. It's not pleasant, but the "flaws" that you allude to were not that evident.
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Old Today, 06:07 PM   #723
soundbloke is offline soundbloke  United Kingdom
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Quote:
Originally Posted by gedlee View Post
This is simply not true. Toole often used this term applied to loudspeaker reproduction.


It bothers me that you keep describing the LF information in stereo channels but then you finish with implications of the whole spectrum. This simply isn't the case. I don't worry too much about the LF stereo problems in real small rooms because these rooms act modally and reflections per see are not relevant - they happen in a time frame too short for our hearing to even detect them. The theoretical comb filtering of central images simply won't occur perceptually in a small room at LFs simply because the ear will integrate the sound from many many reflections thus nulling out the comb filter. Now at higher frequencies where the ear can analyze a reflection and the direct field as separate events there will be a comb filter or more specifically an image shift and coloration. But we absolutely must separate perception in a small room between LFs and HFs as the two things act completely different. In large spaces they are not separate and we can combine the two regions into a single perception.

I too have heard stereo in an anechoic chamber. It's not pleasant, but the "flaws" that you allude to were not that evident.
"This is simply not true. Toole often used this term applied to loudspeaker reproduction."

I have not seen it expressed in such a manner and given its dependence on the recording format and how it is replayed, I find it hard to see how any generalisation is possible.

But adopting your previous method of discussing my posts, lets look at what you said:

"It bothers me that you keep describing the LF information in stereo channels but then you finish with implications of the whole spectrum."

...The impression of space and any envelopment discerned from a recording is, firstly, predominantly a low frequency phenomenon and, secondly, reduced because of the inherent LF reduction in the dipolar S channel information.

"This simply isn't the case. I don't worry too much about the LF stereo problems in real small rooms because these rooms act modally and reflections per see are not relevant - they happen in a time frame too short for our hearing to even detect them. The theoretical comb filtering of central images simply won't occur perceptually in a small room at LFs simply because the ear will integrate the sound from many many reflections thus nulling out the comb filter."

...That is exactly what I have been saying. Conventional stereo reproduction requires those reflections that one might also seek to attenuate in order to enhance imaging. There is also relevant information in the LF S channel that is seldom heard because it is attenuated regardless of any room modes (but obviously ignoring any anti-resonances).

"Now at higher frequencies where the ear can analyze a reflection and the direct field as separate events there will be a comb filter or more specifically an image shift and coloration."

...Did I say any different?

"But we absolutely must separate perception in a small room between LFs and HFs as the two things act completely different. In large spaces they are not separate and we can combine the two regions into a single perception."

...Exactly. And efforts made to enhance one can compromise the other. Better to first remove the need to enhance the low frequency room contributions IMHO.

"I too have heard stereo in an anechoic chamber. It's not pleasant, but the "flaws" that you allude to were not that evident."

...I cannot argue with your perception, but the thinning of centrally-panned vocals when one switches from compensated stereo to conventional stereo has been immediately recognised by everyone I have ever demonstrated it to. And as you have described, it is only the response of the room that compensates for what is "not pleasant" in more normal conditions.
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Old Today, 07:42 PM   #724
gedlee is offline gedlee  United States
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Quote:
Originally Posted by soundbloke View Post
"It bothers me that you keep describing the LF information in stereo channels but then you finish with implications of the whole spectrum."

...The impression of space and any envelopment discerned from a recording is, firstly, predominantly a low frequency phenomenon and, secondly, reduced because of the inherent LF reduction in the dipolar S channel information.
This isn't true either.

Maybe the reduction in S channel LFs is the reason that most bass on stereo recordings is nearly mono. But again, that doesn't matter since at LFs in small rooms we are dealing with modes and steady state conditions because of our hearing limitations. All that matters is the LF steady state sound field, which is easily adjusted to be smooth and whatever gain one wants via DSP. Of course, multiple LF sources adds a significant advantage here as well.
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Old Today, 08:22 PM   #725
33Polkhigh is offline 33Polkhigh  United States
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What ad hoc posted sounds right. Because in an anechoic space you would only get direct sound. So then its the early and late reflections and their position and timing that effects the spaciousness and gives us clues of size and scale.

I would assume the longer the rft the more sense of size you have. Also side reflections give a sense of width and rear reflections depth.

Theres also the issue of flat surfaces vs diffusers, the latter I assume would preserve the frequency response better. Assuming your room isn't a giant pipe then maybe a diffuser is better. At the end of the day its the sense of breadth and space that can make speakers better than headphones imo.

I already brought this up and got no "bites", so last time, how does the speaker off axis response figure in to this? If its not good then it might be better to absorb than diffuse. Why do some speakers seem to tolerate being faced away better than others?
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Old Today, 08:38 PM   #726
soundbloke is offline soundbloke  United Kingdom
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Quote:
Originally Posted by gedlee View Post
Maybe the reduction in S channel LFs is the reason that most bass on stereo recordings is nearly mono.
No, this isn't strictly true - at least not in recorded stereo as opposed to synthetic stereo from the studio. The point is that in recorded stereo the S channel needs boosting to compensate for the 6dB/octave dipole loss - so it is no longer "nearly mono". Any room modes in the listening space are linear and simply added to the signal in the recording, and so not relevant to this part of the discussion either.
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