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Multi-Way Conventional loudspeakers with crossovers

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Old 6th July 2010, 07:10 AM   #4551
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Its not so simple. Remember that 'you are there' sensation requires generating similar reflections from similar angles as the space you want to reproduce.
With 2 channel it is mostly 'they are here' and 'you are looking there trough a wall from a 3m*5m chamber' - if it makes any sense.
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Old 6th July 2010, 11:42 AM   #4552
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For properly setup accurate speaker, shouldn't the "you are there" or "they are here" impression depend on the recording environment and recording techniques?
Good point. Close mic is they are hear vs simple where you can get the room much better. You should be able to hear the differences through the speakers.

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Old 6th July 2010, 11:57 AM   #4553
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Originally Posted by thomasjefferson View Post
Bentoronto's question seems obvious enough: do you have any evidence that this mathematical analysis can point the way to what sounds best to human ears?
Thanks.

People are readily self-deluded, esp. when they have some personal attachment to the device under examination. That is why YOU MUST have blind or double-blind testing to show what factors in directivity matter, if any. Or are we talking about the kind of wine assessments you read in the newspapers?

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Old 6th July 2010, 12:09 PM   #4554
soongsc is offline soongsc  Taiwan
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Originally Posted by daniel View Post
Its not so simple. Remember that 'you are there' sensation requires generating similar reflections from similar angles as the space you want to reproduce.
With 2 channel it is mostly 'they are here' and 'you are looking there trough a wall from a 3m*5m chamber' - if it makes any sense.
It is true that it's not so simple. If the original recording was done in an ordinary live performance environment, the room reflections in the recording environment will be recorded. However, there are a few things that limit revealing playback of these by creating a masking effect.

1. Room reflections and room modes: This is why we have to try to keep these under control.

2. Delayed release of acoustic energy from the drivers: This is why we have to try to keep CSD under control.

3. Interaural of two channel system: This effects everything, and there seems no simple answer how to control this using speakers.
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Old 6th July 2010, 01:38 PM   #4555
gedlee is offline gedlee  United States
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Originally Posted by bentoronto View Post
Thanks.

People are readily self-deluded, esp. when they have some personal attachment to the device under examination. That is why YOU MUST have blind or double-blind testing to show what factors in directivity matter, if any. Or are we talking about the kind of wine assessments you read in the newspapers?
I am the first to agree with your position, but I'm still a little unclear on the specifics. Is there any evidence that directivity matters? Absolutely - just read Floyd Tooles book. Or is there some other aspect of the discussion that you are alluding to. When you made your first comment we were talking about sound power and the kind of scale that would better show sound power versus angle. I did not see how this needed any supporting "evidence".

All researchers in sound now agree that Constant directivity is important. There is some solid evidence but a lot more circumstantial evidence supporting this fact. There is no, or scant evidence as to what the width of this controlled constant directivity should be. Floyd gives some opinions, but they are based on some relatively weak arguments, which even he admits to.

When it comes to directivity then, there is almost no evidence to go on, which, of course, is why there is such a wide disagreement about it. Do we then have to be careful about claims and beliefs - absolutely. But there is a lot of data about how we hear and if one uses this data it is possible to arrive at some substantial hypotheses about what the directivity should be. But the fact is that there are virtually no blind or double-blind tests on directivity to either prove or disprove any hypothesis. Should then we all just pack up and go home? I thnk not. Sure it would be great to do the basic psycho-acoustical studies to put this issue to rest, and if you are willing to fund it, or know someone else who will, then I'll get right on it.

The fact is that there is not likely to be "evidence" in this regard for a very long time. Floyd and I had a long talk about what such a test would even look like and concluded that it would not be trivial. Interaction with the room is a major problem and now its not just speakers that you have to test, but speakers AND rooms. Very quickly the problems become viurtually insurmountable.

Hence, for the forseable future all we have to go on is indirect evidence about how we hear and hypotheses about what kind of directivity best fits what we know.
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Old 6th July 2010, 01:50 PM   #4556
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Earl - Thanks for your efforts in replying.

I think a reader would draw the following conclusion(s):

1. there is no evidence, it's all opinion, and nobody cares enough to test, least of all any vendor who bases their product line on directivity theories.
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Old 6th July 2010, 01:52 PM   #4557
dlr is offline dlr  United States
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Originally Posted by bentoronto View Post
Earl - Thanks for your efforts in replying.

I think a reader would draw the following conclusion(s):

1. there is no evidence, it's all opinion, and nobody cares enough to test, least of all any vendor who bases their product line on directivity theories.
As a reader here, that's not the conclusion I would make.

Dave
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Old 6th July 2010, 01:54 PM   #4558
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Originally Posted by soongsc View Post
For properly setup accurate speaker, shouldn't the "you are there" or "they are here" impression depend on the recording environment and recording techniques?
That would be desireable. "You are there" or "they are here" - what parameters of a room's sound field correlate to which perception? Nobody really knows because no scientific data is available. All we know is that the reflection patter is the key.
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Old 6th July 2010, 03:04 PM   #4559
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As a reader here, that's not the conclusion I would make.
Ditto.


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Originally Posted by gedlee View Post
Interaction with the room is a major problem and now its not just speakers that you have to test, but speakers AND rooms. Very quickly the problems become virtually insurmountable
Yep. And that leads to what? Best Practices? That's about all we can do in the real world. Nothing wrong with making those practices better informed, tho. Seems that is what we all strive for.
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Old 6th July 2010, 03:09 PM   #4560
gedlee is offline gedlee  United States
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Originally Posted by bentoronto View Post
Earl - Thanks for your efforts in replying.

I think a reader would draw the following conclusion(s):

1. there is no evidence, it's all opinion, and nobody cares enough to test, least of all any vendor who bases their product line on directivity theories.
Precisely correct except for "who bases their product line on directivity theories", which is uncalled for, not accurate, and is certainly not possible from the exceedingly small volume of product that I make. But leave off the "slam" and its perfectly accurate.
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