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Recording spatialized/surround speaker setup in space...


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I'm recording the audio for the performance of an electro-acoustic piece in a large rectangular art gallery type space with very high ceilings (i'd guess maybe 20 feet high if not a bit more).

 

The setup of the piece is: one human performer on vibraphone/glockenspiel and vocals at front center stage (which both vocals and instruments will be miced and amplified). There are then 6 speakers, 2 front stage left and right, 2 behind the audience back left and right, and 2 on each side, forming a hexagon around the audience. A tape/computer part will be coming out of the front and back speakers, and the amplification of the performer's vocals and percussion will be coming out of the side speakers.

 

I'm having a videographer shoot video of the pieces, and am wondering how to go about recording the audio live in the space.

 

I have a Tascam DR-40, a pair of SM58s, and a ~$1000 condenser mic with figure 8 polar pattern I could borrow from a friend (i can't remember which mic he has that has this pattern, i just know he has three ~$1000 condenser mics). The Tascam's internal mics can be set to an XY pattern. I have two ideas for the recording setup and was wondering peoples' thoughts and opinions on the setups or if anyone has better ideas.

 

I'm thinking of setting up the mics in the center of the audience, like section off the center of the center aisle, and do some sort of stereo recording, which I'm not too experienced with. My first idea, and probably weirder idea, is to recreate a blumlein pair setup. Basically, have the internal mics of the Tascam facing towards the back in an XY setup. Then have two SM58s facing the front, set up in an XY setup. This might be a dumb idea as you're supposed to have two figure 8 mics in an XY setup for a blumlein pair, and my two front and two back mics are different. But the idea is interesting to me because you have four mics facing different directions from the center point of the room.

 

This second setup idea would also be in the center of the audience, sectioning off the center of the center aisle. My second idea is to do an MS setup with the figure 8 condenser with the SM58 facing front. And then just maybe having the Tascam facing front with its internal mics in an XY setup for possible reinforcement when mixing. I would think the mics will readily pick up sounds from the back speakers, and that's how they'll sound to the audience's ears anyway (coming from behind).

 

Anyone have any thoughts? Am I crazy to try and record live a spatialization piece with 6 speakers surrounding the audience, or could it be cool? The computer/tape part coming out of the front and back speakers gets pretty complex. Would I be just as well off of setting up the Tascam in the center, setting good levels, just using its internal mics and hoping for the best?

 

This is a bit off topic and side point but I also don't understand a few things about how MS micing works. I understand how to set it up and even decode it. My questions are when mixing and have to do with the theory. Once you have your three tracks, bringing up the levels of the two side parts increases the stereo image. I know one sets the side parts extreme left and right, but do people ever pan them somewhat more towards the center but still placed left and right, just not extreme left and right? Is this a technique used for affecting the stereo image? The other thing I don't understand is how your side R part and side L part are 180 degrees different in polarity, but when set to left and right they are still audible. How can they be audible? I also read if you move both side parts to the center you hear silence, because of the polarity differences. But even if you place them extreme left and right in stereo, I would still think you'd hear silence and neither of the side parts, because of their 180 degree polarity difference.

 

Thanks very much for anyone taking the time to respond to this. It's certainly an interesting recording situation where hopefully some people on harmony central have experience with a similar situation. Thanks again!

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This is a bit off topic and side point but I also don't understand a few things about how MS micing works. I understand how to set it up and even decode it. My questions are when mixing and have to do with the theory. Once you have your three tracks, bringing up the levels of the two side parts increases the stereo image. I know one sets the side parts extreme left and right, but do people ever pan them somewhat more towards the center but still placed left and right, just not extreme left and right?

 

Typically, no, but go ahead and experiment with it and see what you think.

 

Is this a technique used for affecting the stereo image?

 

Yes, it will affect the stereo image. No, you probably won't want to go that route due to how MS works... the closer towards center you pan them, the more cancellation you'll get.

 

The other thing I don't understand is how your side R part and side L part are 180 degrees different in polarity, but when set to left and right they are still audible. How can they be audible? I also read if you move both side parts to the center you hear silence, because of the polarity differences. But even if you place them extreme left and right in stereo, I would still think you'd hear silence and neither of the side parts, because of their 180 degree polarity difference.

 

They're the same signal, but 180 degrees out of phase. Pan them both to the center and listen to what happens. :) They'll cancel each other out completely. Panned apart, they don't cancel out since they're isolated to the two individual channels / speakers.

 

If you haven't checked out my articles on Mid-Side and Blumlein Stereo, please have a look - you may find some helpful tips in them.

 

Two tips on your upcoming recording project - get in there in advance and do a trial run / soundcheck before the event if at all possible. The second tip is to remember that the further away you move those microphones from the sound source, the less direct sound from the performers / speakers, and the more room ambience you're going to pick up - and from the sound of it, that room is likely to have a gripload of it.

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