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Using out of phase fallback to reduce spill into microphones

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Using out of phase fallback to reduce spill into microphones

Postby Dodger » Wed Feb 06, 2013 7:45 pm

Hello

I recently recording a choir with a piano accompaniment. I am very happy with the sound i achieved from the choir. However the piano sound was lacking quite alot.

A freind recommended that next time i record the choir. (the original recording were only "test" recordings of a rehearsal with a "proper" recording still to be done.) I record the piano separately before hand then play it back to the choir trough a normal wedge monitor but with the audio inverted? By playing it back out of phase apparently still into the choir microphones would be greatly reduced?

thoughts?

Thanks Alot

Jack
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Re: Using out of phase fallback to reduce spill into microphones

Postby Jack Ruston » Wed Feb 06, 2013 8:49 pm

No. Because:

1. You will most likely find that the piano and choir need to perform live in order to synchronise in free time. They will take timing cues from each other. Trying to overdub in these situations is extremely difficult without doing everything to a click.

2. The trick with flipping polarity to reduce spill relies on having one microphone equidistant between two speakers and then flipping polarity on one speaker. It works up to a point in a very controlled environment where you dont have a lot of ambience flying around. What works more effectively is to record the piano spill on its own into the choir mics, then record the choir, then flip phase on the piano spill only track and sum that with choir track. That would cancel the spill but it's only effective up to a point. The ambience will remain to some extent. A combination of these two techniques can be good. But it doesn't get you around point 1. or point 3....

3. The sound of the piano coming out of the wedge is going to be quite un-natural. That sound, although somewhat cancelled, will still interfere with your beautiful natural classical ambience.

What don't you like about the piano?
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Re: Using out of phase fallback to reduce spill into microphones

Postby Mike Senior » Thu Feb 07, 2013 6:51 am

What he said.

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Re: Using out of phase fallback to reduce spill into microphones

Postby Dodger » Thu Feb 07, 2013 5:49 pm

it was a electronic piano/keyboard with relatively small built in speakers and just didn't sound great in the choir mic's. I could see if i put in trough a slightly better speaker whether that would sound better. I can DI the Keyboard and that sounds ok.

The room wasn't ideal aswell but im going to see what i can do with that trying to find another space. the test recording sound ok towards the end using closer mics into the choir and a good reverb

Thanks

Jack
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Re: Using out of phase fallback to reduce spill into microphones

Postby Jack Ruston » Thu Feb 07, 2013 6:20 pm

Oh I see your problem. I wonder if you can find a space which has a nice piano?

Otherwise I think you're going to find this a problem unless you either get a really nice quality PA (but it'll still sound fake), or give every member of the choir headphones.

J
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Re: Using out of phase fallback to reduce spill into microphones

Postby Urthlupe » Sat Feb 09, 2013 8:48 am

Hi Jack.

I think you already have the best solution. Where the only option is the keyboard rather than a real piano, then minimise the keys as much as possible in your choir array/s and DI the keyboard adding suitable ambience at mixdown.

When I have to use foldback for choir recordings I use small wedges placed as close as possible to the choir and directed away from the arrays. In this way the wedges need very little volume, produce few lo freq's, and are to the greatest possible extent absorbed by the choir rather than bouncing around the space.

Loopy
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Re: Using out of phase fallback to reduce spill into microphones

Postby narcoman » Sat Feb 09, 2013 10:26 am

Hire a nice upright?
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Re: Using out of phase fallback to reduce spill into microphones

Postby Exalted Wombat » Sat Feb 09, 2013 3:13 pm

Dodger wrote:Hello

I recently recording a choir with a piano accompaniment. I am very happy with the sound i achieved from the choir. However the piano sound was lacking quite alot.

A freind recommended that next time i record the choir. (the original recording were only "test" recordings of a rehearsal with a "proper" recording still to be done.) I record the piano separately before hand then play it back to the choir trough a normal wedge monitor but with the audio inverted? By playing it back out of phase apparently still into the choir microphones would be greatly reduced?

thoughts?

Absolutely not! You'd destroy the performance completely. As you would by trying to position the choir so they heard less of the piano.

Better speakers for the piano sound like a good idea. Ideally, move to a better location with a better piano.

But who's the customer? The keyboard may not match YOUR expectation of a piano sound, but the choir are presumably used to it. Are you recording their performance, or trying to produce it?
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Re: Using out of phase fallback to reduce spill into microphones

Postby Dodger » Sun Feb 10, 2013 8:48 pm

The recordings are not for anything of particular importance just a bit of fun really. i was trying to gain experience in recording larger ensambles as its something i've always wanted todo

last time i recorded them. it was just a rehearsal but hopefully if we decide (ive got my fingers crossed because i really want todo it) to go for a short EP then ide hope they would let me produce it more.

as there is a completely 0 budget it is just for fun really i dont think renting a better space would be an option regrettably.

i think i will just have to go wedge monitors as quite as i can get away with and roll off sub 300 htz?

ill get some copys of the test recordings and put them onto sound cloud tomorrow and see what you guys think

thanks again for all your advice

Jack
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Re: Using out of phase fallback to reduce spill into microphones

Postby Urthlupe » Mon Feb 11, 2013 12:57 am

Your attitude is spot on Jack. Go ahead, and enjoy

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