What I have learned about home audio: Setting up a HT in a common area is a whole bunch of compromises.

Due to access issues with a cabinet, I needed to relocate my left and right mains.

I did a little re-arranging, and now have the speakers sitting on shelves in my entertainment center.

The good news is that the tweeters of my front soundstage now line up fairly well, and I can set my M3's upright for optimal horizontal dispersion. I can also toe-in the speakers for improved on-axis listening, and the added height helps to fill the larger area with sound as opposed to being blocked by furniture in the room.

HOWEVER, the shelves are only 10 inches deep, and NOT open at the back. As a result, there is not much clearance for the port at the rear of the M3.

I have the fronts crossed over at 80hz.


Would any of the Axiom Gurus here please help me out with the following?:
1) Is port clearance an issue considering my crossover point?
2) Any tips on taming the resonance of the bookshelves?

Thanks!

Maybe try plugging the ports with a sock? That will lessen the frequency response of the M3, but if you are crossing them over with a sub it won't matter so much. You're kinda making them sealed monitors. Maybe worth a try?

St_PatGuy,

Thanks for the suggestion! I never considered sealing up the port!

Would anyone know if the 80hz x-over point be okay with the drop in low end efficiency if I plugged up the M3?

Thanks!

I have a pair of Monitor Audio GR10s that came with a foam plug for the ports. While it did reduce the low end output, it helped out the boominess I heard when I had them in a small room.

Hope it makes a difference for you!

Well, I went back to '02 to read some of Alan's posts regarding plugging up the ports, and basically he mentioned that it wasn't a good idea.

From 9/23/2002:
"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..."

Also read some other posts that mention keeping the speaker as close to the front edge of the shelf as possible to cut down on boundary/reflection issues.

Guess I'm doing some experimenting tonight!

Yeah, Brian; maybe you've already read this, but as long as you have say 3" of "breathing room" for them, don't worry about the rear ports. Also yes, don't have them recessed in the enclosure, but rather have them protruding 1/2" or so to minimize diffractions and reflections.

Thanks JohnK. I may not have more than 2 inches clearance in the back, though I'll see what it looks like after I pull them out further.

Also read some posts by bigjohn who seemed to have thing for ports...

Fun going through the old stuff!

Well, good thing you didn't take me at my word!

Yeah, Brian; bigjohn once made(what he thought was)an innocent remark about his enthusiasm for the ports on his Axioms. No chance when we got ahold of it and speculated about the lewd and indecent activities going on. When the new EP400 sub was announced as being sealed without ports, it furnished an opportunity for this board classic displaying the chagrin he felt upon learning of this. John's presence is sorely missed, but recalled this for your enjoyment and that of other newer members.

St_PatGuy, thanks for the suggestion all the same!

JohnK, I hope I didn't stir anything up by mentioning bigjohn as that was not the intent. I know he doesn't post anymore and don't know the circumstances around why that is. I just enjoyed reading some of his old posts!

I moved the speakers out as much as I could and have just about 2-3in clearance in the back, so I'm thinking I'm fine there. I ran the Audyssey calibration and it knocked off 8dBs from both speakers in the 65hz region and 4-5dBs in the 85hz band to help take care of the boominess due to the placement. Or at least that is what I assume.

Everything sounds okay so far, and I didn't hear any of the other items on the shelves rattling around, but I need more time to sit down and listen.

Thanks again for the help!

Mahalo!
Brian

I do not believe any one knows why big john disappeared, at least I can't think of it. BigJohn just disappeared as did Sushi and a few others, Mojo being the most recent I can think of, luckily for me I still visit with mojo from time to time

I remember bigjohn said that most of his computer time on the forum came while he was at work and he wanted to set a good example because he was in a supervisory role.

At least that's what I think he said once?

Brian, no problem; your mentioning bigjohn brought back memories of the humor which everyone(including John)displayed about that topic and reminded me to link Mark's hilarious "Man of the Year" post.

The bookshelves in the bookshelf is working out fine with the exception of all of the vibrations that are transfered to the shelf. Even at moderate levels, the vibrations are easily felt. While the volume of the music being played seems to drown out any audible resonances that the shelves may produce, I can't help but think that they are adding an unwanted color to the material.

Would I need to decouple the speakers from the shelves or am I worried over nothing much?

Probably and probably

I think the speakers come little stick-on rubber feet - do you have them installed ? If not a trip to the local home building store should offer all kinds of gummy alternatives.

I normally mount bookshelf speakers upside-down on bookshelves, mostly to get the tweeter at listening height, but it means the feet go on top of the speaker. That's another argument for using something other than stick-on feet between speaker and shelf

Some high density foam will help too.

If you feel like spending a couple bucks MoPADs helped a great deal under my center channel which is on a glass shelf.

Edit: Or the SpeakerDudes.

Thanks for the suggestions!

I have the speakers upside down as well, so I'm shying away from the sticky rubber feet right now. The auralex products look interesting!

I've used mouse pads in a pinch under mics and speakers as well...

Initially I was looking at resting the speaker on a sandwich of mousepad, half of a cement cap, then mousepad.

May still try this one out just to see.

We'll have to approve of any images on the top mousepad.

Roger that.