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stereo symmetry

Posted: Tue Aug 24, 2004 7:04 pm
by the dreamer
hi,
i don't understand, why the stereo symmetry is still balanced in a CR-layout like the one attached. in detail: one side glass, fully reflective - the other side slats where certain frequencies are "trapped".
my reasoning is that there is a difference between left-right reflections from the backwall then. or is the backwall fully absorbtive???
do not understand this as critisism of john's design, which is not my intention and i'm certainly not in the position to do so. i just don't understand the physics involved here in order to keep up an undistorted stereo image and want to learn why it works so well. :oops:

thanks a lot
dreamer

Posted: Wed Aug 25, 2004 3:42 am
by giles117
The slats are dual purpose, they maintain the symetry in that like the glass they are reflective. The added benefit is that they trap midrange frequencies as well.

The rear of your room (in this case) is absorptive to prevent/reduce/eliminate the sound from reflecting back into your mix field.

Posted: Wed Aug 25, 2004 4:16 am
by the dreamer
hi bryan, thanks for clearing this up.
another one: when looking on a surround-setup like below, it seems to me that i get direct reflections from the rearspeaker-opposing walls to the mix position.
if i remember right, this is actually your room setup remodeled to fit into this plan. what's your experience?

thanks

Posted: Wed Aug 25, 2004 5:41 am
by giles117
Looks similar to a design I did for a surround room we are building.

Any way, the way I designed that room was to have full on absorption above and below the rear speakers. That way the only real reflective surface is the face of the speaker. Not enuff to jack up your mix field.

And in the rear where you have it listed as slats. that is incorrect. all that is absorption. There are no slats beyond the inital area as the room is quite short.

Posted: Wed Aug 25, 2004 6:11 am
by the dreamer
i uploaded a new pic in my last post to make clear what i mean. the red line shows the path of the sound.
or are your sidewalls angled down??? did i miss that?

Posted: Wed Aug 25, 2004 6:33 am
by giles117
Well now that is the number one issue but then your surround speakers are not nomrally LOUD when you are mixing. Plus the idea is to aim them just behind your head. So reflection is not a major concern from your rears. :)

It sorta comes with the territory.

Posted: Wed Aug 25, 2004 6:39 am
by the dreamer
thanks bryan! that's good news.