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Discussion Starter · #1 ·
I finally connected the BFD (parametric equalizer) to my dual SVS 20-39PC+ and have taken measurements, correcting for the RS meter...If it matters, the room is 30 by 18, with sloped ceiling from 8 to 12 feet. The subs were crossed at 80 and the front speakers were on for the calibration. If I should take readings with only the sub connected, please let me know. Denon 3803 and Sony 755 DVD player as the source, playing test tones.


Here is the curve, with the green and yellow lines representing individual readings from each of the SVS 20-39PC+ subs and the red line representing a combined reading (with both subs turned on). I am looking for some suggestions on the best way to set up the curve for home theater AND for music (for music, presumably with only one sub).


Thanks in advance. (also posted to av123).
 

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I would see if you can play with positioning to get rid of that huge null at 80Hz before you start EQing. Try a corner. Or, from that graph it looks like your subs are out of phase with your mains.


You should also EQ with no crossover, ie up to 150Hz or so. The idea is to get the flattest response before applying your crossover.


Also, are the subs in the same position?


Steve
 

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Discussion Starter · #3 ·
Quote:
Originally posted by Steve Dodds
I would see if you can play with positioning to get rid of that huge null at 80Hz before you start EQing. Try a corner. Or, from that graph it looks like your subs are out of phase with your mains.


You should also EQ with no crossover, ie up to 150Hz or so. The idea is to get the flattest response before applying your crossover.


Also, are the subs in the same position?


Steve
Steve, thanks for the comments. Positioning is limited. Although this is a big room, it is used for many other things and the subs are now in their home space. They originally were behind the screen, but the entertainment center shook too much and I had to move them out. Cornering is not an option.


The subs are located about three feet behind the seating area (six home theater seats accross in a curved configuration). The subs are next to a wall, about 2/3 from one end of the room, and are separated by a bookshelf that is the height of the subs (about four feet wide).


I will check the phase of the subs. Someone on another forum mentioned that this could be an issue as well.


And I will make sure to EQ with no crossover. I had wondered about this, and your post clarified that issue.
 

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You might try turning one subwoofer off, and then optimizing the phase of the single subwoofer to the rest of the system...trying to smooth out the curve as much as possible. Then add the second subwoofer and tweak its phase control to the first subwoofer.


Tom V.

SVS
 

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quote:

--------------------------------------------------------------------------------

Originally posted by Steve Dodds


You should also EQ with no crossover, ie up to 150Hz or so. The idea is to get the flattest response before applying your crossover.


--------------------------------------------------------------------------------


Can you give a further explanation? Do you set the crossover frequency on the sub to the max value (or turn it off if possible)? What about the crossover on the AV receiver which is usually set to 80Hz when you set it for "sub on" and front speakers to "small"?


Then after EQ, do you reintroduce the crossover to the original settings?


Sincerely,

Snooktarpon
 

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It depends on your crossover. If you have the ability to bypass it or set it higher you should do that. The problem with having the crossover engaged is that you no longer know what you are EQing to., ie you have no easily identiifiable target.


If you have a fixed crossover you'll just have to make do.



Steve
 

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When I saw the graph I first thought it looks like a phase issue between the subs and main. I did what Tom V mentioned to get my subs to work correctly.


Steve,

Wouldn't the FR curve with and without the crossover be different? So why wouldn't you want to get the response flat with everything setup the way you would normally listen?
 

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Discussion Starter · #8 ·
Quote:
Originally posted by TV
You might try turning one subwoofer off, and then optimizing the phase of the single subwoofer to the rest of the system...trying to smooth out the curve as much as possible. Then add the second subwoofer and tweak its phase control to the first subwoofer.


Tom V.

SVS
The subwoofers individually follow a very similar curve (shown on the graph). Those numbers were obtained by turning one sub off and getting raw data for the other.
 
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