1. I've been looking at the Axiom M22s because they are short enough that I could put them underneath the screen. I would love to buy Axiom M80s but my receiver won't be able to handle the 4 ohm load and they are wide enough that a 110 inch screen is all I can do. If I were to get the M60s then my receiver would be sufficient but I still would be limiting the size of the screen and the speakers would be in the corners.
Acoustically would I be better off with M60s in the corners or M22s under the screen about 2 feet from the walls? I plan on buying the center and surrounds from axiom over the next year
Despite your room being very long it’s not really that big volume-wise so I think you could use the M22s very effectively. I and others have compared the M22s to the M80s and when used with a good subwoofer like you have they sound almost the same. The only difference I can detect is that there is a little less mid-upper bass in a large room using the M22s + sub vs the M80s +sub.
I was in the same situation as you in deciding screen size and went with one size smaller than I could have fit just so that I could fit my front 3 speakers under the screen giving me full placement flexibility for the best front soundstage. IMO you will have a better overall theater system if you use a speaker screen combo that lets you get the speakers out of the corners.
Though I’m not a big fan of them but in your situation with a room that long have you considered using an acoustically transparent screen? It would allow you to have the M80s you want and still have some placement flexibility to move them around behind the screen so they aren’t in the corners. It will cost more both in screen and speakers but if you really want towers. . . .
2. I'm thinking of putting new carpet in my basement. Is it a bad Idea to put the speaker wire under the carpet? I will be hiring a professional for this. What kind of padding should I use under the carpet for the best audio?
I’ve never permently put wire under carpet but have put it under rugs w/o ever having a problem. Though it’s more expensive there is flat speaker wire which might help if you plan on using a wider gauge that might show under the carpet. Make sure to run all the wire you thing you might ever need like for dual surrounds (that’s a long room), height/wide speakers in case you ever might add them later.
3. Acoustics: I have no clue what I'm doing. What should I do to improve the sound in my room? Please see post below for room and equipment details.
Bass traps? Acoustic panels? I want to go the DIY route to save money
I wouldn’t actually start treating the room until you have your speakers set up and tweaked for best sound. Then you can start listening for what treatments might help the problems you can’t deal with by positioning.
As a general rule below 200Hz is best dealt with by equalization. To be effective at very low frequencies acoustic panels (traps) must be very big and still EQ often does a better job. Also in a rectangular room running two to four subwoofers is likely to be more effective that room treatments. However, in my personal experience multiple subwoofers may not work in oddly shaped rooms. Mine is “L” shaped and dual subwoofers doesn’t work for me.
Other treatments above 200 Hz are effective for dealing with specific problems like first reflections but until you have your speaker positioning finalized it’s hard to know what they are.
4. Any clue what my SVS PB-10 NSD crossover should be? Should it be "enabled or not"? I have enabled and at 80 right now. What is the phase and what should it be set to?
Generally it’s advised to disable/bypass the crossover on the subwoofer and use only the one on the receiver. This avoids “cascading” crossovers which might cause the roll-off of the subwoofer to be to steep. However, I remember reading an article (Alan wrote I think) where he suggested trying just that, using both the receiver and sub crossover set to the same frequency saying that in some cases it helped make a smoother transition between the speakers and the subwoofer. If I can find the article I will link to it.
A couple of other notes. My room is somewhat long 13x21 (ok not close to yours) and I find the biggest acoustic problem compared to my last more square room 12x14 is blending the front speakers with the surrounds. In the smaller room I got a perfect 360 degree soundstage using just 5.1. In the longer room I’m still getting a gap in the coverage between the mains and the surrounds using 7.1. I’ve found that using “wide” speakers really helps fill in that gap by wrapping some of the sound from the mains out and around the sides. So even if your present receiver doesn’t support wide speakers I would make sure to wire for them in case you ever want to give them a try.
Similarly you might also consider using dual surrounds at some point. If you have multiple rows of seating in a room that long I think you would get much better coverage by having more than one surround speaker on each side (just like in movie theaters). Again something you might want to consider for the future and pre-wire for.
Just my thoughts.
Cheers,
Dean
