Why Stereo?


I have read quite a few posts on here and other forums about having a stereo PA system. I don't know why anyone would want that. If you have different sound coming out of different speakers, you only get a true stereo image at one line in the theater. It also adds complexity to the rig that one probably doesn't need.
Stereo is something many BEs want for effects. A common use is panning cymbals off center.
Why not go stereo its easy to do and provides great effects for live sound.

In theatre use it's great for accomplishing panned surround effects and the such. I do agree in a theatre application when it comes talking heads on stage a single mono point source has far better acoustics than comb filtering speakers from different zones.
Take your favorite song into some sort of wav editor and merge the stereo channels into a mono channel. What happens? It loses its deminsion. Adding deminsion and effects. Why not wonder why people want 5.1 Dolby? That's a lot more complex and in my opinion has no live application. (My theater has a 5.1 set up. Why? I don't know. It's been here longer than I have, but you can create some really awesome thunder if you know how to use the Echo Layla console.)
all i have to say is why not?
Unless one has a true stereo setup there are lots of reasons. A lot of "stereo" setups are more accurately categorized as dual-mono setups. In such a setup the stereo image is present to a few people in the middle. They basically resemble an isosceles triangle with their head and the speakers. To everyone else the stereo image is not present, and so they are missing out on the sound that would come from the speaker they are not hearing. With a true stereo setup there is even coverage from the left and the right everywhere in a venue, and then there isn't a good reason not to, but with a dual-mono there is reason not to.

Also, in some cases one might select mono over stereo so that they can bridge their amp/amps and get more power out of it/them.
Austinro said:
you only get a true stereo image at one line in the theater. It also adds complexity to the rig that one probably doesn't need.

With line arrays and driveracks the stereo image is much better and more easily accomplished than it used to be. I crew movies in the park in Chicago once in a while (typical crowd is 30-50,000 outdoors) and the stereo image is still very distinct at about 500 feet. Imagine showing Star Wars (which we did last year) in mono. It would have been horible and the audience would have noticed. I think we used 18 JBL vertec tops and 24 subs.
Even with stereo getting easier to accomplish I don't see much application in theatre, and less with live bands. Anyone on the left or the right of the speakers is going to have a poor stereo image, if any at all. I also don't see great benefit in it. Maybe I'm just too small minded.
During the occasional talent show (which usually wind up being battle of the bands), I run the mains stereo, but, since only a few rows of chairs would fit between the mains and the back wall (or FOH, for that matter), I set up mono side fills. That set-up worked out very nicely. Plus, I've seen it done in arena concerts. U2's vertigo tour had the main clusters stereo, but the sides and rear audiences only got mono mixes.
It also depends on your space. Some spaces are more suited/designed for Stereo while other places are a bi-Mono system. A couple of spaces that I work in are ment for true stereo and you can hear it no matter where you sit. It makes a difference and it also adds another demension to the sound.

Dustin Strobush
ETC Systems group
BenjaminD said:
How would one go about setting up a true stereo environment? What is the theory behind setting that kind of system up?

Everyone everywhere in the venue can hear the left and the right speakers at equal volume coming from the left and the right.



As you can see in the poor text diagram above speakers are at stage left and right. Those on the left aim to coverage on the left and the right, and speakers on the right cover the left and right too. I'm sorry for the curdity of that model, its not to scale. (Any Back to the Future fans???)

Hope that helps.

soundman1024 said:
I'm sorry for the curdity of that model, its not to scale. (Any Back to the Future fans???)

Are you telling me you built a time machine... out of a Delorean?

while i dont know much about sound, there are some points where i agree mono is better then stereo for the whole audience.
then again, why dont we just do it the Cirque Du Soleil way where they had stereo speakers in every single seat in the house for their show KA, plus general stereo sound.
there was an article a while ago in pro lights and sound, pretty interesting.
by any chance, does anyone have a link to that article? i lost my copy of that issue.
Mbenonis, that article was exactly what I was looking for! It explains the diagram perfectly. That would explain why there are so many speaker positions in my auditorium... now if I could only get up to them!


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