best way to arrange my speakers

[dragonfyr]

Speakers mounted 2-3 feet from an adjoining surface on the wall or ceiling (and speakers mounted on stands 2-3 feet from the wall) commonly create an acoustical problem. This results in a ~3-millisecond delay.

A direct arrival followed by a short reflection 3 milliseconds later will manifest itself as a huge dip at ~160 Hz plus additional dips at higher frequency multiples (comb filtering). Consider the effect this might have on vocal and speech fundamentals.

It is better to hang them 6-8 feet from adjoining surfaces if space permits, or to hang them abutted tightly to the adjoining surface. If doing the latter, the problem frequencies will be higher, where horn directivity can help reduce the reflection and/or a small patch of appropriate sound absorbing material selected specifically to absorb the frequency pass band should be placed on the ceiling to absorb the reflected signal.

Note: All the above applies to multiple signals arriving at similar levels. If the reflection or second arrival can be reduced to 10 dB less then the first, then frequency response anomalies will be less than 1 dB.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

[DuallyDave]

DrWho,

Thanks for the long and thoughtful reply. While that all sounds great in thoery, I think it might be too problematic for my situation. I already have the wall mount, I guess I can take it back, but I like the idea of having more space in my somewhat small living room. To mount my plasma at 45 degrees in the corner, I'd have to set it on a stand or get a more expensive mount. I had my RPTV in the corner for a while, with the fronts on each side of it, and that worked fairly well with that setup, but required my couch to be back by E, and I had to squeeze by it all the time, so I got tired of that after a while (I need a smaller couch!). My recliner was at D for that layout, I can have it there for the C location also. Actually I can put it a little towards A, and have more room to lean back.

While near ideal imaging would be great when watching HD and DVDs, in real life I watch plain old SB most of the time, so the tradeoff would probably not be worth it. If I go with C, I figure I can put my rears high on A and B, so my LR would be in front of the window as you say, but the RB5 would probably fit better there, being smaller. I think that might be the way I will go, after reading these replies and thinking about it more. I can leave my couch at A, and corner mount my fronts by the A corner next to the couch, with my sub under it, and next to the door by E. While I would get more reflections as you say, I think I should probably go for practical rather than ideal, a tradeoff for sure. I would also have lots of room by my TV for the component rack - still looking for a under TV rack that is wider rather than taller, and something that looks more like furniture.

Also, there was a sale this weekend, if I buy a Denon receiver, I get a free Denon DVD player. I decided to do that, my JVC receiver and DVD are ok, but I keep hearing great things about Denon, and I wouldn't mind having 6.1. I figure I can mount a back speaker by my computer desk, maybe get another RB5 if they still sell them. If not, maybe an RB15 would be a good match. As long as I'm upgrading to a plasma, I can upgrade from 5.1 to 6.1 also. Even though the Denon is a 1705, bottom of the line for that series, I suspect it might sound better than my JVC, which tends to distort when I approach 50% volume. I don't know that I have room for two more back speakers if I got a 7.1 receiver. I've never had a Denon, but they seem to be very popular among home theater types. I just want a cleaner sound. Might have to go with more reference series speakers front and center at some point.

[DuallyDave]

I upgraded 3 speakers also, might as well do it all. I'm going to use my RB-5s in the front, got an RC-25 for the center and RB-15s for rears. The KG3.2s will become the rear centers for 7.1. Should sound great! Hopefully these bookshelf speakers won't be too small for home theater use, I don't crank it up too loud. I'm just looking for clean sound at a reasonable volume.