The challenge is to adjust the rear array level, delay and EQ so you shorten the decay as much as possible. Getting the frequency response good is easy. The decay is a lot more work to get right. The trick is to identify each resonance and apply EQ on the rear array to each of them. As little as 0.1 dB change can make a large difference. The same goes for the Q of the rear array EQ points. Here’s my rear array EQ. Many EQs with high Q as you can see.
Wouldn't it be best to equalise it before displaying it that way, otherwise the waterfall may be displaying artefacts of a less smooth response?
It can be done in an L-shaped room.
Here's a document on it (in German)
http://hannover-hardcore.de/infinity_classics/!!!/DBA im L-Raum.pdf
Here's a document on it (in German)
http://hannover-hardcore.de/infinity_classics/!!!/DBA im L-Raum.pdf
There are a few "rules" that applies to get the best performance from a DBA, of which I haven't satisfied any of them... even so, it works very well.
1. Rectangular, "shoe-box" room
2. All surfaces as stiff as possible
3. Subwoofers mounted at the room's surfaces, or as close as possible
4. Nothing inside the room that can affect the plane wave - meaning no furniture and no absorption
1. Rectangular, "shoe-box" room
2. All surfaces as stiff as possible
3. Subwoofers mounted at the room's surfaces, or as close as possible
4. Nothing inside the room that can affect the plane wave - meaning no furniture and no absorption
There are at least a couple of reasons. The most important one is that the front and rear array is supposed to eliminate standing wave modes and boundary reflections in the entire room, not just for one listening position. The front array has to be close to the front wall to avoid comb filtering off the front wall. It will also ensure that the front array can energize all standing wave modes in the length axis of the room. Because - the rear array will absorb the length modes more effectively that way. The rear array needs to be close to the rear wall for the same reasons. The sound pressure from the length modes are strongest close to the rear wall, and thus the active absorption will be most effective with the rear array close to the rear wall.
Could be wrong, but I think that side-mounting will only achieve an added beneficial effect at higher freq.s to deal with the diffraction effects of the baffle.
Standard back-to-back w/delay should be fine for more modest-sized subwoofers below about 100Hz, and if the baffle is much larger then perhaps 80Hz.
It might still be relevant though if you do NOT have a steep low-pass filter for the sub's crossover.
I achieved more directivity with side mounted woofers than rear, in Vituixcad. That's looking at forward projection, that is, the forward side 180 of the 360.
Hi guys, I am Old man(54) from Germany. As always an interesting topic. I have a HT with Magnepans and 15“ Multisubs in a L-room. 2 Subs in the Front and 2 Subs in the Back . The back wall is damped with 60cm Rockwool. The subs sound good but not good enough for me 😬. Therefore, I am currently damped the front wall with 60cm Rockwool and there will be another 4 subs. Each 2 pieces on the sides . In the niche come another 2 pieces and are set as active absorbers / used. Sorry for my English I have to work with translator.
Paule
Paule
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Here is my WTF and FQ from the old setup.
1. 4 Multisub
2. 4 Midbass in the Front
3. sub+midbass
4 WTF Sub
5 WTF Midbass
1. 4 Multisub
2. 4 Midbass in the Front
3. sub+midbass
4 WTF Sub
5 WTF Midbass
