I know every room situation is different, but about how far from the back wall does a M50 or M60 need to be for optimum sound. I have no experience with rear ported speakers. I have large front ported floorstanders in the living room that sound great right up against the back wall. (Don't have Axiom's....YET!)

i think optimal would be anywhere from 10-18 inches. but you can play with it to get the best sound.

i have my M60's a little over a foot out, and toed in to the listening position.

bigjohn

TW, just considering the rear ports alone, 3-4" of "breathing room" is enough. Beyond that, the woofer cones should be at different distances from the three nearest room surfaces(floor and two walls), but the distance from the wall behind isn't a critical matter in itself.

I've experimented placing my m60's anywhere from 3" to 18" from the wall, and toeing them in or not. They seem to sound great no matter what with very little if any difference in sound quality to me.

That's good that you are able to place you speakers without any trouble. Sometimes it takes days of trial and error to properly place speakers. If you are still looking at fine tuning the placement, a good formula is this:

To determine the distance from the wall behind your two front speakers, measure the distance between the floor and the ceiling (in inches) and multiply by 0.618; and, to determine the distance from the side walls, measure the width of the room (again in inches) and divide by 18 then multiply by 5.

After that you can move them back or forward, out or in, and fine tune it.

To make sure I understand you minirock:

When I move everything down to the basement, which should be done soon..

Distance behind mains:
108in. x .618 = 66.74in. ? does this make sense, seems a bit to far, unless your talking about mm's.

Distance from side walls = 180in / 18 x 5 = 50in. This seems fairly accurate.

These calculations are based upon acoustic ideals and do not take into account that you may have a spouse or furniture.

You got it! And like Peter said, other circumstances may come into play since not everyone has a dedicated HT room, so don't feel like the formula has to be followed exactly.

I thought maybe you had messed up on the wall-to-main formula. In my case with 9' ceilings, your calculation says to have 5ft. 6in. of space behind the mains. Seems a bit to far, especially when Axiom says 2-3in. to let the ports vent low bass into the room.....although, for those that remember the old Maxell cassette tape commercial, where the guy is sitting in the middle of a room with a loudspeaker right in front of him, and his hair is blowing backwords....maybe there is some truth to it...

LOL! Oh man! I barely remember that.

The front wall to speaker measurement did seem odd to me too, but again it's more for ultimate rather than practical placement.

It's all good man, I guess I'm showing my age.

>>These calculations are based upon acoustic ideals and do not take into account that you may have a spouse or furniture.

... or, even more limiting, a spouse AND furniture !!