DIY acoustic equalizers

In February I recorded a fantastic concert (review from The Watchful Ear) put on by Bang the Bore in Southampton.  It was located in the Castle Vaults, under the town centre and consisted of a performance of Alvin Lucier’s classic, I am sitting in a room and a top form set from John Butcher who does things with a saxophone which must be heard to be believed.

As a large part of what was going on in this gig was reacting to the space (John Butcher has an ongoing ‘Resonant Spaces‘ project), I thought I’d try and record as much of the room without it getting too muddy.

Omnidirectional microphones, pickup the most room sound but need to be placed within the critical distance (closer than the with directional microphones) to receive more of the direct sound from the performer rather than reflected sound from the walls of the room.  I was looking at recording outside the critical distance, in the diffuse field (where there is more sound reflected from the room) so needed to improve the directivity of my microphones but retain the flat frequency response down to low frequencies that the omni’s have.

You can do some of this using EQ on a mixer.  Alternatively you can affect what happens to the sound before it gets to the microphone by creating a reflective baffle around the microphone, which I intended on doing.  DPA already make these for their microphones, but they’re £75 each (ow!) and don’t fit my AKG’s.  So went out to the local shops in search of foam balls…

I came back with a pair of ‘Dog Balls’ from “Magic Prices at Just Jeff’s” (yes, it’s really called that) and an apple corer.  Total cost was under £3. And lighter than a mixer 🙂

Unfortunately the apple corer wasn’t the best tool for the job:

however (with some pain and awkwardness) did get through the balls *ahem*.

and managed to squeeze a microphone through:

although they did look a bit silly they did do the job, however the room wasn’t as reverberant as I expected.

I’ll see what’s happening with the recording- if it gets put up somewhere I’ll add a link

 

 

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