Room setup/speaker placement

[Krusty]

Due to a fireplace and other objects, I am trying to determine the best wall to set my L,C,R and HDTV on. The room is 19' * 18'.

Would placing the HDTV and Center Channel in one corner of the room work? I could then place the Left Main two thirds of the way down the left wall and the Right Main same on the right wall. Then all three would be pointed at the main seating position and form an arc.

I also need to see what my options are on placement of the four surround speakers, what will work and what will sound the best. The surrounds will be mounted on the walls, so it is not practical to trying several locations. Using the above layout would create a circle of speakers around the main listening position.

Any downsides?

[Woochifer]

Actually, an arc is one of the more commonly suggested placements because a center speaker should be aligned slightly behind the main speakers so that the front three are truly equidistant to the listening position. If you have to position the center speaker in a straight line with the mains, then it's preferable to increase the delay timing for the center channel in order for the sound from the front speakers to all arrive at your ears around the same time. Start with a 5.1 setup. Get the L/R surround speakers right before you start messing with the back surrounds. If you have to resort to a bizarre placement with the back surrounds, it could make your setup sound a lot worse than with just the basic 5.1 setup. Keep in mind that most soundtracks are mixed and optimized for 5.1 anyway.

The diagram below is the ITU reference alignment, which is commonly used in recording studios for multichannel music mixing. This would be a good starting point. I use it in my system and it worked so much better than all of the other alignments that I've tried, I just placed it this way and left it alone.

The degree to which you toe-in the speakers into the listening position depends on your preference and how your speakers sound pointed directly at you versus slightly off-axis. Keep in mind that this alignment was optimized for 5.1 music mixing. With direct-firing surround speakers it might sound too localized with some movie soundtracks. For setups that will playback both multichannel music and movies, Dolby recommends mounting the surrounds about 2' above ear level and pointing them directly at one another. This gives you the directionality and imaging cues from 5.1 music and a lot of newer movie soundtracks, while diffusing the sound just enough with older movie soundtracks or those with mostly ambient sounds.



Any downsides would depend on your room acoustics. Because you're using an assymetrical alignment, the reflections off the side walls will not be consistent. The first thing you need to do is get a SPL meter ($40 from Radio Shack) and make sure that all of the speakers are set to an identical level. The assymetrical alignment could cause the speakers from one side of the room to play louder than the other at your listening position.