I think it would be worth a couple experiments before you go spending any money. I've got two ideas for you as to why you're having trouble. Maybe we can come up with a way to determine if either of them is the cause.
The low position of the center channel speaker is the first guess. Like BIG suggested, line-of-sight for the second row may be the problem. Also, the proximity of the floor may be causing interference (SBIR
) that creates a frequency response dip which may be in a troublesome frequency region for dialog. To test these hypotheses, maybe you can temporarily rig up the speaker up in front of the screen on a stand - at least high enough that you can see it clearly from the second row. Listen to a couple troublesome clips and see if that's a solution.
My second possibility is harder to test. There is the possibility that untreated resonances are masking other sounds. A sound in the recording may be unusually amplified by the acoustics of the room, making it harder to discern other sounds in a nearby frequency range.
Read about the phenomenon at wikipedia here
Determining if masking is the problem won't be as simple, but you might start with a casual analysis of the troublesome clips; are they "busy" sonically - especially in the lower frequencies (below around 300 Hz)? "Yes" would suggest masking may be likely. Continue with some test tones of varying frequency - hopefully a sweep of frequencies (like the kind generated by REW
); listen (or measure) for strong peaks in the response. If you find that bass response is strongly uneven, you may be dealing with some strong room resonances (eigenmodes
), and potential masking as a result.
If masking is the problem, you'll need to do some more thorough analysis and maybe some treating as well as EQ.
Of course, I could be striking out here - let us know if this gets you anywhere.
FredEdited by HopefulFred - 11/4/12 at 7:22pm