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Posted By: rbr back ported axiom speakers - 06/25/08 04:53 PM
Hi everybody!!: I only have experience with front ported speakers, e.g., JBL S-312. I'm interested on the Axiom's M-60 or M-80 speaker, but I see they are front and back ported. Do these speakers need to be very far from the walls?. I'm concerned as to how far I would have to place them from the wall, I only have about 20 inches (about 51cm) max from the wall to place them. I would have to toe them in with an angle of about 18 degrees. I would appreciate you input.
Posted By: Haoleb Re: back ported axiom speakers - 06/25/08 04:59 PM
20 inches from the wall to the back of the speaker would be fine, (if thats what your reffering to) I currently have mine setup 31 inches from the wall to the back of the speaker at the nearest point but I dont have anyone else to complain about them being in the middle of the room.

20 inches from the back to the front of the speaker is quite a bit less than ideal.. to say the least.
Posted By: Ken.C Re: back ported axiom speakers - 06/25/08 04:59 PM
You don't need to have them very far from the wall at all, usually; just a few inches. However, your room may vary. Why such an extreme toe in? I wouldn't start planning exact locations until you get the speakers. Be ready to play with placement; it can make a big difference.
Posted By: AdamP88 Re: back ported axiom speakers - 06/25/08 05:02 PM
I only have my M60s about 10 inches from the wall and though I'm sure I could pull them out and tighten up the bass a little more, they sound fantastic where they are. Besides, pull them out anymore and they're asking to get knocked over by the dogs when they get overexcited.
Posted By: Ken.C Re: back ported axiom speakers - 06/25/08 05:06 PM
I think my 80s are about 6 inches from the wall, btw, with zero toe in at the moment.
Posted By: terzaghi Re: back ported axiom speakers - 06/25/08 05:12 PM
I have my m80's about 8 inches from the wall and they sound great
Posted By: EFalardeau Re: back ported axiom speakers - 06/25/08 05:13 PM
Distance from the back wall is one thing. The very important other thing is distance from the side wall to avoid corner effects.
Posted By: Haoleb Re: back ported axiom speakers - 06/25/08 05:17 PM
I guess i'm just part of some kind of audiophile freak show! I never did like putting them real close to the back wall \:\)
Posted By: rbr Re: back ported axiom speakers - 06/25/08 05:21 PM
Thanks, I mean 20 inches from the back of the speakers, I did not visualized the toe in angle well, I would be about 10 degrees only. No problem with side walls plenty of space to place the speakers from the side wall. I'm just concerned on unnatural sounding reflexions of the wall, and not being able to place them further into the room.
Posted By: Wid Re: back ported axiom speakers - 06/25/08 05:26 PM

When measuring the distance from the back wall the most important thing to remember is to measure the distance to the baffle where the middle of the speakers drivers are. Same when doing side measurements, measure to the middle of the speakers driver.
Posted By: Hutzal Re: back ported axiom speakers - 06/25/08 05:27 PM
 Originally Posted By: terzaghi
I have my m80's about 8 inches from the wall.


I guess 8" is enough room for some men...
Posted By: SirQuack Re: back ported axiom speakers - 06/25/08 05:49 PM
8" here. \:\)
Posted By: terzaghi Re: back ported axiom speakers - 06/25/08 05:55 PM
hey, not all of us have 20" to play with like rbr
Posted By: Hutzal Re: back ported axiom speakers - 06/25/08 06:21 PM
 Originally Posted By: terzaghi
hey, not all of us have 20" to play with like rbr


20" must be a PITA ;\)
Posted By: fredk Re: back ported axiom speakers - 06/25/08 06:50 PM
4' here, but I have a mancave so...
Posted By: JohnK Re: back ported axiom speakers - 06/26/08 01:25 AM
RB, welcome. As far as the rear ports go, the only requirement is to give them some "breathing room", and about 3" would be enough for that.

A more significant placement measurement would be to have the distances from the front wall, side wall and floor to the middle of the woofer cone unequal, if possible. The reason for this is so that the peaks and valleys caused by reflections from the room surfaces don't all pile up at the same frequencies.
Posted By: Nick B Re: back ported axiom speakers - 06/27/08 11:08 PM
What about the ceiling? The distance to the ceiling not equal to the floor, front and side walls is what you mean right? Also, I thought that you were supposed to make sure that those four distances aren't even divisible by one another. It seems like this would require a little bit of time since the m60's and m80's have 3 and 4 woofers respectively. My head hurts just thinking about it.

- Nick
Posted By: JohnK Re: back ported axiom speakers - 06/28/08 02:53 AM
Yeah, Nick; theoretically the ceiling should also be taken into account, but it usually isn't considered, since it would be very unusual to have a placement where the distance of the woofer cone to the ceiling was identical to the distance to the floor and both walls.

No, the evenly divisible lengths factor applies to the size of the room and the resulting modes. The reflections from the nearest room surfaces are a completely separate effect.
Posted By: CooLJ92 Re: back ported axiom speakers - 07/09/08 11:48 PM
Why does Axiom M60 and M80 have 3 ports (two rear and one front)compared to other speakers which only have one or two in the rear? And why doesn't the VP150 doesn't have a port? Just curious...

jj
Posted By: anthony11 Re: back ported axiom speakers - 07/10/08 12:09 AM
The M60 are bigger with more drivers. IIRC the tweeters, midranges, and woofers are segregated by internal bracing, which would seem to come into play.

As for the VP150, many people will place it inside a cabinet or stand of some sort, so it's designed for different constraints, eg. not being able to assume that there's room for a rear port to breathe.
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