Audyssey & Multiple Subs

therealjeepguy

Ok, before any of you rag on me, I searched the forum on this, but didn't find a thread on it, so here goes. I have an Onkyo TX-SR707 with dual sub outputs. The owner's manual states that both jacks produce the same output and I get that, but it says nothing about how the receiver discerns the difference in distance between two or more subs in a multiple sub configuration when running the auto-calibration. Has anyone else encountered this dilemma before?

thsmith

Yes, I have had 1 true sub and 2 mid bass modules (same principle). The best thing you can do is learn Room EQ Wizard (REW) SW that is free at hometheatershack.com.

Once you have the 2 subs EQed to the room then run AUD. This and room treatments will give you best results or buy a bass auto eq device which can be at least 3 times more expensive than learning REW and a BFD1124.

AUD will never set 1 sub correctly little lone 2, IMO.

kuntasensei

Both jacks produce the same output, but if your 707 is anything like my 1007, it should calculate the proper distance/delay for each sub (it pings each sub separately during MultEQ setup), then perform its equalization based on the summed output. I humbly disagree with thsmith about Audyssey's abilities to equalize a sub, considering I got smooth enough results with my SVS to take my standalone EQ out of the equation altogether, but I respect his take on it. Plus, while REW is a valuable tool for equalizing your system, it doesn't look at weighted first impulse response across multiple locations the way Audyssey does, nor does it help you correct issues in the time domain (which is especially important with multiple subwoofers).

That said, Audyssey is very much "garbage in, garbage out". You need to use a tripod for the mic, ensuring that you do as many positions as your AVR allows so that it gets as much data about your room's acoustics as possible. First position should be where your ears are, in line with your center channel, making sure the mic is slightly above the back of your couch. The remaining positions should be at least 2 feet to the left and right of center, then the same positions mirrored a foot or two further into the room. Standard MultEQ allows 6 positions, so that should have you covered. If you have 8 positions to work with, 7 and 8 can be anywhere within that rectangle you've formed. With all these positions, make sure that you aren't moving the mic extremely to either side of your front soundstage. If your mains are spaced out very far apart, towing them in slightly can help ensure that you aren't getting so far off-axis that the sound will drop off, and help keep your mic positions for Audyssey within a good area to detect the room's acoustics.

therealjeepguy

So, Kunta, I'm guessing that when you hook up a second sub, the receiver should detect it and ping each seperately? That's what I wanted to know. I still haven't decided whether I'm going to implement a second sub into my configuration yet. Mostly depends how well the new sub works...when I get one, that is. I think I've pretty much decided that I'm going with a HSU Research ULS-15. The large driver will displace plenty of air to energize my relatively large room and the sealed design offers better transient response...can't wait!! The only drawback I can find with this sub is that I don't think it offers continuously variable phase control, but that's a small issue that I'm willing to compromise.

Oh, and thanx for the link to Hometheatershack, thsmith. I found some very helpful ideas and cool links there!! I added it to my favorites!

kuntasensei

Yes, it will ping each separately and assign a distance setting to each. It does this to ensure that both are in phase with the other channels before it starts EQ'ing the summed output.

That HSU should absolutely rock. Honestly, the continuously variable phase control is nice to have but largely unnecessary, since the distance/delay adjustment in your AVR essentially acts to ensure proper phase alignment and Audyssey should sort out the rest of the time issues. The important thing is that if it has a phase switch, run some test tones in the crossover range to see whether 0 or 180 is optimal for your placement BEFORE running Audyssey. In my setup, I don't have a phase control at all because I run a passive SVS sub off of a rackmount amp. But I can reverse phase by swapping positive and negative at the amp, and reversed phase ends up being the proper setting for my particular placement.