Axiom Home Page Forums General Discussion Technical Questions M3ti's in my small, square, reflective room...

I have had my M3ti's for almost one year and, in all honesty, I love them. A month ago I moved from a 12x12 room with thick carpet and modern sound-absorbing walls into another 12x12 room this time with hardwood floors, hard plaster walls, and a 9 foot ceiling. I've slowly worked the m3's into an "optimal" position of 3 feet in from the rear wall and aimed just in front of my listening seat (a big futon couch). But, when the music gets complex or bassy, I still lose detail and can hear "boominess" along with distinct resonant peaks on certain notes. Honestly, they are at 70% what they were in my old room! Asides from wrapping my room, speakers, and stands in eggcrate foam, do I have any hope of fixing this problem? Does the rear port contribute to the reflections and resonance -- ie, can I stuff something in there? Is my apartment a hopeless acoustical nightmare? Or, *sniff*, should I start looking for a smaller sealed-box speaker?

Any thoughts or ideas would be greatly appreciated...
Thanks!
-Jon

Hi Jon,

The bad news is that square rooms are the worst possible dimensions for standing waves, which produce areas of exaggerated bass frequencies and regions of cancellation that are dictated by the dimensions of the room.

Don't stuff anything in the M3ti's port. You'll change the integrated design of the woofer, enclosure size and venting and the results will be unpredictable and degrading to the response. There are better ways to alleviate your difficulties.

Do you have your speakers on stands? How high are the stands? The trick to reducing the effects of standing waves is to place the speakers so that the distances between the M3ti's woofer (and its diameter), the floor, and the nearest wall (either behind or to the side) are all odd numbers and different--not multiples of each other. Since the M3ti has a 6.5-inch woofer, make sure you don't have it on stands that are a multiple of that dimension; likewise the distance from the rear wall. Also experiment with moving the futon couch. Where you sit is just as important as the locations of the speakers in terms of standing waves that cause "boominess". Try moving one or the other at first (the speakers or the couch).

That should help, but you could try an asymetrical setup of the M3ti's, perhaps firing diagonally across the room. An area rug with a spongy underpad would certainly help, but it won't fix the standing waves.

Good luck and keep us posted. By the way, forget egg crates. They won't help.

Regards,

Very interesting. I hadn't thought of the stand height affecting resonance ... if I put my hand on the stands, I can actually feel them vibrating at a specific frequency (which I suspect is also radiated into my room). They are perhaps 25" tall at present and are adjustable in height.

My original intuition was to find damping materials ... but adjusting speaker placement should be much easier. I do have an area rug (without padding) that probably helps a bit.

Thanks Alan for your advice, I will keep playing...

--Jon

Jon, Alan has given you some good suggestions, but as he indicates, the main problem is your square, highly reflective listening room. In very technical acoustics terminology, your room sucks. Short of extensive architectural changes, which you can't do, or room equalization equipment, which is probably more expensive than you have in mind, the improvements will be limited.

The 12 foot wall separations lead to especially nasty resonances at about 47hz(1,130 ft/sec speed of sound divided by 24 foot round trip)and the second harmonic at 94hz. Changes in speaker and listener placement can't entirely overcome this, but may prevent a bad situation from getting worse. As Alan points out the woofers(and your ears)should be unequal distances from the floor and two walls( e.g. 1,3,5 feet). You could even try the M3s directly on the floor, tilted back slightly. Heavier upholstered furniture, rugs, open doorways,etc. help a bit. If you have some old speakers, placing them in the corners works to some extent as a bass trap. Good luck.

Thanks JohnK... I have a coat closet in the left corner of the room... leaving the door open makes a dramatic improvement! Thank you for that idea. There is still a hint of resonance between 100 and 200 hertz, but it is much improved. I am thinking about adding some tapestries or quilts ... I suspect it is possible to decorate a room with sound in mind. :-) Thanks for the advice, things are starting to look (sound) better in my lousy room...

-Jon.