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Posted By: GeorgeHudetz Front main speaker offset question - 01/13/07 03:49 AM
I’m struggling with room layout restrictions, and have a question about speaker offset from the front wall (talking front mains, here).

It’s common to hear advice that the mains should be positioned 1 to 3 feet front the front wall. My understanding is that this rule of thumb is mostly appropriate for rear-ported speakers. True?

Assuming that is correct (and even if it isn’t) I’m wondering if a good quality acoustic panel (such as a Gik 244, or a reduced size version of same) positioned on the wall directly behind the mains would allow me to sneak a M60 or M80 (or even a M22 bookshelf, for that matter) closer to the rear wall. I’m having a hard time getting that clearance – I need the speakers to be fairly close to the wall (less than 12” from back of speaker to wall) and it’s limiting my speaker choices. I’m really salivating at the thought of some M80s, but I’m concerned about the clearance.

Any insight, or other advice on handling this problem?

FYI, my room is 14’ wide by 16’ deep with 9’ ceilings. The right side opens up into the kitchen and a lofted entry so I’ve got some funny acoustics (and more effective volume than the basic dimensions suggest). Yes, it’s a shame I can’t take up a bit more of that 16’ by moving the speakers forward, but the WAF is at play here. And, I’m looking to build a 5.1 system, but music SQ comes first, then movie SQ.

Thanks for any comments.
Posted By: JohnK Re: Front main speaker offset question - 01/13/07 04:19 AM
George, welcome. That 1-3' "rule of thumb" has little factual basis. With respect to rear-ported speakers such as the Axiom mains it's been said(by Alan among others)that only a few inches are necessary to give the port "breathing room". The port aside, rather than a specific distance from a wall, it's more important to have the distances from the woofer cones to the three nearest room surfaces(usually the two walls and the floor)unequal, so that the reinforcements(and weakenings)of response that occur at certain frequencies and distances don't all "pile up" at one frequency when these distances are identical. If the back of the speaker is a few inches away from the back wall, results should be good if the side wall is say 3' away. A satisfactory positioning can certainly be worked out with a little experimenting.
Posted By: HomeDad Re: Front main speaker offset question - 01/13/07 04:56 AM
George, having owned the M60's prior to upgrading to the M80's and having similar restrictions in placement, I can tell you that I found with the 80's I needed a minimum of 8 inces from the rear wall for them to sound right, the 60's were more forgiving and could be placed several inches closer.
I orginally had my 60's about 4 inces from the rear wall and they sounded great, when I upgraded to the 80's and put them in the same footprints they sounded terrible, I then pulled them out about 4 inches and they sound fantastic. If you can leave some room the 80's are great, but the 60's are also terrific speakers, you can't go wrong with either. Hope this helps, good luck with your choices.
Posted By: GeorgeHudetz Re: Front main speaker offset question - 01/13/07 05:14 AM
Thanks for the input, guys. It's good to hear I can make it work in my environment. It seems like the M60s are the better choice for me, given their lower sensitivity to placement, and lower power requirements (I'm running a Yamaha recevier).

Homedad, at the risk of a little thread drift, I'm curious about how the M60s compare to the M80s - or perhaps you can direct me to a thread?

Thanks again!
Posted By: HomeDad Re: Front main speaker offset question - 01/13/07 05:39 AM
The M60's sound very similar to the M80's, the M80's will play louder, and to me they sound for a lack of better words a bit fuller, but that may well be because of my acoustics and room size.
I think you would be more than happy with the M60's, the main reason I upgraded was that the room the M80's are in is about 50'x 20' with 11' vaulted ceilings and I wanted a lttle extra power.
Posted By: jakewash Re: Front main speaker offset question - 01/15/07 08:48 PM
A few inches should be more than enough room unless you are operating the speakers at very high volumes. Look at how much air gets moved into the throttle body of an engine, and that opening is pretty small.....
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