TOPIC:

Hi all. Owner of a SHD studio with two subwoofer at different distances each other and from mains.

I tried some approches to get the best xover with mains but all of them were unsatisfactories.
First i tried setting delays on plugin with values from a REW diferrences about sub and mains (each sub individually), then i tried with difference about added mains (L +R) and added subs ( L+R).... was not good.

Then my approach was doing same strategies (first idividually then on pairs) with single sweep on dirac and reading diferent delays when this sweep was inserted on a dirac slot. Different delay on plugin was used to try a new sweep... also not good.
Anyone has a better approach to blend two subwoofers and mains?

I initially used phsical measurements for time alignment between mains and a single sub but due to the acoustic centre of subs not always being obvious it didn't work very well. As soon as I used REW for time delay measurement it all worked well. It is somewhat involved using REW properly but the numbers do seem to work even if the views are odd.

www.minidsp.com/applications/auto-eq-wit...measuring-time-delay

I can see no reason why multiple subs would not work the same. There are cunning methods of dealing with multiple subs but they do little more than jumble the peaks and dips around im ny view. Dirac can better deal with frequency response issues as long as the time delays have been properly compensated. The time delays should be derived and compensated for before any use of Dirac because Dirac is a 2 channel system and doesn't understand subs.

Can you please post a picture of your set up so we have a better idea of what you are dealing with?

entripy wrote:

I can see no reason why multiple subs would not work the same. There are cunning methods of dealing with multiple subs but they do little more than jumble the peaks and dips around im ny view. Dirac can better deal with frequency response issues as long as the time delays have been properly compensated. The time delays should be derived and compensated for before any use of Dirac because Dirac is a 2 channel system and doesn't understand subs.

Sure!. I understand this.clearly, but with two subwooffer you can set delays individually or through REW get the sum of them, using resultant curve.
I did both methods resulting in delays for mains between 16 and 25 ms....

None of them like to my ears, so asking for some other method

TacTZilla wrote:

Can you please post a picture of your set up so we have a better idea of what you are dealing with?

Yes, i'll do. In advance i must to say it is not a very rare setup. Room are 4.10 x 4.20 x 3.5 (yeah, almost a cube....arghh).
MLP are on 38% of frontwall. Mains are 2 meters from MLP symetrically. One sub placed at right wall beside front R at 3 meters from MLP and the other sub on left wall but far from front left to get minimum interferences with first sub (REW measured and working)

But, obviously delays are critical.... must i looking for subs individuals delays related to mains, or must get the sum of them and further delayed related to mains?
And how to do it? Through REW? Or doing a 'fake' dirac attemp with no delays and getting distance resultant as a delay and doing the real dirac attemp?

The speed of sound in air is roughly 1ms per foot so if your mains were delayed 16 to 25ms it suggests the subs are 16 to 25 feet behind the mains relative to your listening position which seems rather a lot.

The actual time alignment of subs is also not usually that critical because the wavelengths at those frequencies are so long. Their delays need to be measured and compensated individually though. They may turn out to be the same but they may not depending on their positions.

Also, note that Dirac can't control all problems. Particularly Speaker Boundary Interference Response (SBIR). Correct placement of subs in corners is necessary to minimize that problem, Dirac or EQ cannot help at all with SBIR.