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Posted By: KGC M2 placement - 5" wall clearance enough? - 09/15/07 11:55 PM
Hi - I'm brand new here, and though I searched some, I couldn't lock on to the specific information I need.

I am ever closer to committing to a pair of M2 v2's - but worry about colouration due to lack of space. I can give them 5 inches out from the wall, but no more. I will be crossing them at 80 Hz to a sub.

Any thoughts?

Thanks in advance.
Posted By: Ken.C Re: M2 placement - 5" wall clearance enough? - 09/16/07 01:03 AM
Sounds fine to me.
Welcome KGC,

I think you will be just fine, that should allow plenty of room. My m80's are about 6-8" from the back wall. You may also experiment with different toe in angles towards the listening position...
Posted By: KGC Re: M2 placement - 5" wall clearance enough? - 09/16/07 01:52 AM
Thanks, and "sounding fine" is, of course, what I want.
Posted By: KGC Re: M2 placement - 5" wall clearance enough? - 09/16/07 01:55 AM
Thanks for the reply - those big M80's are front-ported, though. The M2 is ported rear-wise, which is my concern.
Posted By: JohnK Re: M2 placement - 5" wall clearance enough? - 09/16/07 02:05 AM
KG, welcome. 3-4" is enough to give the ports "breathing room". All speakers get bass reinforcement when placed close to one wall(the distance of the mid-woofer cones to the floor and the other wall should differ), but this should be an advantage for the M2s.
Posted By: Mojo Re: M2 placement - 5" wall clearance enough? - 09/16/07 02:34 AM
That's a good question and it deserves a complete answer.

Speakers are omni-directional at low frequencies and highly directional at high frequencies. At low frequencies, the interference between the speaker's direct and rear wall waves creates re-enforcement commonly heard as a "boom". As the frequency increases, the phase of the reflected sound lags the direct creating cancellations.

At some frequency, the reflection will be delayed so much as to be in opposite phase relative to the direct sound creating a rather significant first order dip in the frequency response. At 5", the dip will take place at about 575Hz.

If you could move the speakers 3.6 feet away from the wall, the first order interference dip would occur below the lower cut-off frequency of 80Hz. Your problem would then be solved.

You aren't that fortunate so you have to resort to a different scheme; locate the speaker as close to the wall as possible. This will decrease the time delay of the reflection relative to the direct sound. This moves the interference problem to a higher frequency where the speaker's own directivity decreases the rearward radiation. Note that this will boost lower frequencies but these will be cut off from the M2s anyway because they are being sourced by the sub. Alternatively, the bass boost may be pleasant and more preferable than the sub for some styles of music.

The drawback to positioning the speakers closer to the rear wall is reduced sound-stage depth. Since you only have 5" to work with, sound-stage depth may already be compromised.

So, armed with this knowledge, you will now have to experiment to achieve the most appealing reproduction for your ears.

And like Randy says, toe them in.
The m80's have 2 ports on the back, and 1 on the front. fyi
Posted By: KGC Re: M2 placement - 5" wall clearance enough? - 09/16/07 04:43 PM
Thanks for that info - I wondered if there may be more ports kicking around in the back - just full of holes, aren't they?
Posted By: KGC Re: M2 placement - 5" wall clearance enough? - 09/16/07 04:44 PM
Thanks, according to the next responder, closer to the wall may be the answer - which is counter to what I was thinking, of course.
Posted By: KGC Re: M2 placement - 5" wall clearance enough? - 09/16/07 04:47 PM
Now, thats' a solid analysis, and gives me something to work with. Still not going to be easy to solve for my placement situation, but now I have the parameters.

Thanks very much.
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