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Old 3rd January 2013, 07:01 AM   #101
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Quote:
Originally Posted by dewardh View Post
No . . . the comment was more sarcastic than serious. MS matrixing only works when capsule/"driver" spacing is a fraction of a wavelength.
That's why it works well with most recordings
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Old 3rd January 2013, 08:20 AM   #102
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What's the next step for the experiment? A FRS8 at center too or will you try e.g the Nathan there and see if the tonality is a problem?

I really like nearfield bass. Not having to worry so much about neighbors is relaxing, and I also think that the lower overall bass in the room makes things sound better (less boomy) from another room. Do you add a delay or not worry about it?

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Originally Posted by markus76 View Post
Yes, those are FRS8's but I got it to "work" with Behringer P2031A's and B200's too. Very different speaker concepts. They simply differed in tonality but not in spatial properties. The important part is level, timing and spectrum of the reflections.

The near field subs are crossed in at 150Hz for the FRS8's.
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Old 3rd January 2013, 08:29 AM   #103
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Originally Posted by SEdwards View Post
What's the next step for the experiment? A FRS8 at center too or will you try e.g the Nathan there and see if the tonality is a problem?

I really like nearfield bass. Not having to worry so much about neighbors is relaxing, and I also think that the lower overall bass in the room makes things sound better (less boomy) from another room. Do you add a delay or not worry about it?
Adding a FRS8 center is next. It's already in use for surround playback.
I'm currently revisiting Gerzon's Trifield paper from 1991 ("Optimal Reproduction Matrices for Multispeaker Stereo").

Near field bass is fantastic. A high cut-off adds envelopment. Stereo bass finally might make sense in a small room. Needs to be tested though.
To answer your question, yes I did add delay to the subs.

Last edited by markus76; 3rd January 2013 at 08:33 AM.
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Old 3rd January 2013, 07:13 PM   #104
Elias is offline Elias  Finland
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Quote:
Originally Posted by markus76 View Post
I'm currently revisiting Gerzon's Trifield paper from 1991 ("Optimal Reproduction Matrices for Multispeaker Stereo").
Why not simple passive matrix with coefficient 0.5 for starters ?

Gerzon had so many theories it will take a life time to try them all..


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Old 3rd January 2013, 08:59 PM   #105
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Originally Posted by markus76 View Post
Also please try the side wall setup I've shown. There's something "special" about this.
I've had my Nathan's set up in a standard 30 stereo triangle away from the walls, with a 45 toe-in. The loud contralateral reflection had a detrimental effect on imaging. With the speakers directly at the wall, the problem is completely gone. The resulting reflection pattern seems to aid reproduction (spaciousness and depth).
The contralateral reflection is indeed a detrimental one in my experience. Perhaps such a wide setup compensates for the reduced channel separation with a summed centre?

Anyway, I need to build me an extra speaker first
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Old 4th January 2013, 12:11 PM   #106
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Originally Posted by Elias View Post
Why not simple passive matrix with coefficient 0.5 for starters ?

Gerzon had so many theories it will take a life time to try them all..


- Elias

Wrote a little script for Reaper. The matrix factor can be varied with a slider:

Code:
//=================================================
desc: 2to3


slider1:0.5<-0,1,0.05>Matrix Factor (0-1)

//=================================================
@slider
matrix_factor = slider1;

//=================================================
@sample
l_in = spl0; r_in = spl1;


//create MS from Left/Right
m = 0.7071*(l_in+r_in);
s = 0.7071*(l_in-r_in);


//Re-matrix to Left/Right
l_out = 0.7071*((m*matrix_factor)+s);
r_out = 0.7071*((m*matrix_factor)-s);


//output
spl0=l_out; // Left
spl1=r_out; // Right
spl2=m*matrix_factor; // Center

//=================================================

Here's the schematic:

Click the image to open in full size.
Attached Images
File Type: jpg linear_matrix.jpg (12.8 KB, 161 views)
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Old 4th January 2013, 01:08 PM   #107
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Reaper code for "Optimum Linear-Matrix" based on Miles:

Code:
//=================================================
desc: 2to3 //based on Miles http://milestech.com/aesimpre.htm


slider1:0.5<-0,1,0.05>Matrix Factor (0-1)

//=================================================
@slider
matrix_factor = slider1;

//=================================================
@sample
l_in = spl0; r_in = spl1;


//Optimum Linear-Matrix
l_out = l_in-(matrix_factor*r_in);
c_out = (1-matrix_factor)*(l_in+r_in);
r_out = r_in-(matrix_factor*l_in);


//output
spl0=l_out; // Left
spl1=r_out; // Right
spl2=c_out; // Center

//=================================================
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Old 4th January 2013, 01:14 PM   #108
Elias is offline Elias  Finland
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Quote:
Originally Posted by a_tewinkel View Post
Anyway, I need to build me an extra speaker first
More people shoud do that, really I think thy biggest hindrace of experimenting with matrix stereo is people ususally have only two speakers.

Thinking about it, it does not make much sense to me to try to reproduce images in the center with speakers placed only at the side ! The whole concept of two speaker stereo is based on compromised technology some 80 years ago. Even more incomprehensible is people accept it just like that without questioning


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Old 4th January 2013, 01:19 PM   #109
Elias is offline Elias  Finland
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Quote:
Originally Posted by markus76 View Post
The matrix factor can be varied with a slider:
Have you though about dividing freq bands in Gerzonic manner, as he seemed to emphasise the importance of different hearing mechanisms along freq bands that should be taken into account in the matrix ?
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Dipole Bass vs Monopole Bass Stereophonic Sound from a Single Loudspeaker 3 Speaker Linear Stereo Matrix Wavelets
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Old 4th January 2013, 02:20 PM   #110
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Originally Posted by Elias View Post
Have you though about dividing freq bands in Gerzonic manner, as he seemed to emphasise the importance of different hearing mechanisms along freq bands that should be taken into account in the matrix ?
Not yet. Currently listening to the "basic" versions.

Interesting observation: the center doesn't seem to be particularly stable with head movements. The stability of phantom sources don't seem to benefit from an additional speaker. Phantom sources created by only two speakers (L-C and C-R) is probably preferable.
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