Below is my standard procedure for dual subs with Audyssey. The sub crawl does work
with multiple subs.
It's not the end of the world if the subs aren't equidistant to the MLP either. If you're really worried about getting them time aligned, get an AVR that can do dual subs or a MiniDSP.
When you perform the Audyssey calibration, keep the mic positions tightly clustered around the MLP (I know this goes against the Audyssey standards, but trust me, it works better). Only move the mic a couple of inches at a time between measurements, to either side of the MLP (I just rotate the mic boom). I typically do the first measurement at the MLP, 3 measurements to the right (in 2"-3" increments), the same on the left, and then the final measurement back at the MLP.
You mention gain/level matching as if they are the same thing...they are not.
Level matching = matching each subs level at the MLP with an SPL meter.
Gain matching = matching the gain of each sub to be equal, typically with extreme nearfield measurement (1"-2" from driver) with the sub placed in a neutral position (middle of the room)
Personally, I prefer gain matching. See this post by Craig John.
One last comment...get your seating away from the back wall for God's sake!!
EDIT: I see now that that green couch may not be the MLP, hard to tell from the pics....is the MLP up against a wall as well?
Set the gain on both subs to the same level - around 12:00-2:00 on the gain knob is a good starting point (just a starting point, gain structure can vary greatly from one manufacturer to another). Set phase to "0" on both subs for now.
1. Connect sub #1
only and place it at the MLP
2. Do the sub crawl to determine the best position for sub #1
3. Place sub #1
in that position
4. Connect both subs and place sub #2
at the MLP (with sub #1
playing as well)
5. Do the sub crawl to determine the best position for sub #2
6. Place sub #2
in that position
7. Playing the AVRs test tone, adjust phase on one of the subs until you get the maximum SPL at the MLP (could be variable or a simple 0/180 switch)
8. Run Audyssey, first mic position only, and "calculate"
9. Look to see where Audyssey has set your sub trim, you want it to be around -5db to -8db ideally
10. Adjust the gain on both subs by the same amount
up or down as needed
11. Repeat 8-10 until you get the sub trim around -5db to -8db
12. Run the full Audyssey calibration
13. Set all speakers to "small"
14. Set all crossovers to 80hz (or, if set higher than 80hz by Audyssey, leave them alone)
15. Bump up the sub trim by 3db to 6db to your preference
Hope this helps!