Surround Speaker Placement

[jesyjames]

I posted this over at Home Theater Forum, but as you guys are the Polk experts I'd be remiss if I didn't solicit your opinions as well:

My current set up exists in a 12 x 10 room, with the television on the longer wall. Owing to a door that opens into the room, I have my surround speakers directly to the sides of the couch, but they are mounted about 7 feet high(in other words: in the small place between door and ceiling). Now, they strike me as quite high. There's about a foot of space between the speaker itself and the back wall. So picture me on a couch, with the speakers directly to the sides, up about 7 feet(to the bottom of the speaker). The speakers are dipole/bipole switchable(Polk FXI30s). My brother was over last night and he made the suggestion that I could mount them on the back wall, positioning them so that they frame the couch, and then put them about 2 feet above your head and switch them to bipole. In this case, they would be a lot closer to me, but not touching the ceiling. I must preface my question by stating that he and I agree it sounds pretty dang good where they are. They sort of sonically disappear into the room and it's great. Our concern lies in loss of detail and clarity owing to the considerable off axis positioning from the tweeter. What I was wondering is if anyone has been in a similiar situation and what you found to be best. The best thing to do would to be to "try" it out, but as that would necessitate drilling more holes in the wall I'd like to solicit some opinions first. Do you think it would create a better soundstage if I were to move the speakers to the back wall, lower their height, and switch to a bipole design? My couch is flush with the wall, so that is my primary concern. I'd be so close to the speakers. But, if this would be an improvement I'm all for doing it.

Thanks for any and all suggestions.

[ken brydson]

You're right. It does all boil down to what sounds best to you. To avoid drilling mounting holes to "try" the setup, someone in another related thread suggested using ladders or something to temporarily get the surrounds into the new location.
Just a thought, it will save you some sheetrock repair if you don't like it

[seaslug]

Based on personal experience with a pair of f/x300i's, I think that you might prefer to leave your surrounds right where they are. Your concerns about detail and clarity are justified, but that's sort of the point of surround speakers--at least in an HT setup. Dipole speakers mounted directly to the sides of the listener create a diffuse soundfield that is perfect for the ambient effects found in most movie soundtracks. If you do move the speakers to the rear and switch them to bipole, the effects will be much more localized, and the speakers will draw attention to themselves. I think that most listeners would agree that this is not desirable with any format other than multichannel music, in which case you would probably prefer monopole surrounds, anyway. Just my two cents.

[Tour2ma]

Pretty much ditto the above... Your i30's are only about 1' above the "ideal" position.

The tweeter dispersion is good enough that being off-axis the additional 10 deg's that you are is not going to cut into their performance dramatically. Dispersion should be fairly smooth up to 70 or 80 deg's in any perpendicular plane. Any decent dome tweeter can achieve this.

Moving your sides to the rear would give you some very weird movie experiences to say the least, as that's still a sides signal going to them.

If anything you might want to toe them "down" a bit. By that I mean angle them with their tops further away from the wall than the bottoms. This would direct more sound to your listening position, It's analogous to toeing in your mains. If the mounting screws are in wall studs backing them out a bit, the top more than the bottom, should give you a taste. Again a 10 deg “lean” should be all you need to compensate for that extra foot of height.

Slightly over sized washers on the screws will keep the heads from chewing up your keyholes. If you like the lean you may have to do something to better brace them to kill any vibrations. If you don’t like it better, just go back like you were.

[jesyjames]

The other concern then is that I had read you need a good few feet from the speakers and the back of the wall in dipole mode, otherwise the early refelections will muddy the soundfield. Now, I've only got about a foot of space between them and the back wall with them as they are now. How serious of an issue is that?