ProSoundWeb Community
Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Josh Billings on July 16, 2011, 10:59:19 PM
-
Like picture a typical 2 stack system...but stacked really close to each other and each angles in 45 degrees so they speakers fire through each other's paths.
Would you get any comb filtering from such a setup? I know it doesn't make sense for an every day application, but I'm curious if it would affect the sound? Lets figure a perfect world of no other reflections just the speakers them selves creating sound that overlap each other.
Josh
-
Like picture a typical 2 stack system...but stacked really close to each other and each angles in 45 degrees so they speakers fire through each other's paths.
Would you get any comb filtering from such a setup? I know it doesn't make sense for an every day application, but I'm curious if it would affect the sound? Lets figure a perfect world of no other reflections just the speakers them selves creating sound that overlap each other.
Josh
No.
-
Like picture a typical 2 stack system...but stacked really close to each other and each angles in 45 degrees so they speakers fire through each other's paths.
Would you get any comb filtering from such a setup?
The 2 speakers will not change each other's characteristics, but as with any pair of speakers with the same program material, anywhere where you can hear both speakers at about the same level, and they are slightly different distances from the listener, there will be comb filter interference. Whether they cross each other, or are splayed away from each other makes no difference other than where you can hear them both.
Mac
-
Like picture a typical 2 stack system...but stacked really close to each other and each angles in 45 degrees so they speakers fire through each other's paths.
Would you get any comb filtering from such a setup? I know it doesn't make sense for an every day application, but I'm curious if it would affect the sound? Lets figure a perfect world of no other reflections just the speakers them selves creating sound that overlap each other.
Josh
When I do "speakers on sticks" jobs, I almost always cross-fire two 15"+horn cabinets rather than placing them on either side of the stage. I've modeled this (using G.P.A.) and while it doesn't eliminate comb filtering entirely, the results are much better than two speakers on either side of the stage, two speakers on one side both facing the same direction, or even two speakers together, splayed.
The exact angle you want to use will be dependent upon the coverage pattern of the horns, however.
I've got some pix here (http://www.plantation-productions.com/gigpix/Beatlemania.html) where I just did a show with my mains cross-fired (two SRX 725 columns on each side). Still have comb filtering because I've got two sources (three, actually, including a delay stack), but the amount of combing is reduced because each stack isn't producing quite as many nulls and lobes. In this particular setup, the delay stacks weren't far enough back, but other than that the sound was great (a Beatles tribute band, not super loud, we were shooting for 90-100 dB around FOH).
I'd definitely search on the web for the "G.P.A. Acoustical Modeling Program" and use that to model your sound system to see what happens when you want to try a new layout.
BTW, running "speakers on sticks" in a cross-fired arrangement works really great. All speakers, cables, amps, etc., are in one spot. Don't have to tape down long cable runs, looks less "trashy" in a classy place (once people get past the fact that it doesn't look "normal"), and the sound is significantly better. It's not quite a point source, but comes about as close as you can get when you're running the same material through both speakers. Of course, if you're running stereo material through the speakers, you're not going to get the spatial separation needed for the stereo effect.
Cheers,
Randy Hyde