Baffled stereo is an interesting technique, and with many possible avenues for experimentation. My video episode "Stereo" covers this; in that episode you'll see me using, among other things, a home-made Jecklin disk. This page covers the disk in more detail, including how I made it, and some more comprehensive tests.
More information on the Jecklin Disk:
(i.e. the what-do-I-have-around-the-house disk). While stuck in the lockdown, I decided that it was time to experiment with baffled stereo. Since the Jecklin disk is a pretty easy setup to make, and since I had just about enough stuff in hand, I gave it a go, and this is the result.
The basic idea is to use two miniature (lav) mics, clipped on to each end of a thin rod which is pushed through the baffle. This makes for a very simple mounting system.
The disk itself is basically two pieces of circular foam core, about 35cm across, stuck together. Then some ¼" soft foam is glued on to either side, and a fleecy fabric over that, all fixed with spray glue. The disk ended up 37cm across overall.
A 7mm wooden dowel is shoved through the middle, cut to length so that when the lav mics are clipped to the ends, the centres of the mics are exactly 36 cm apart (18 cm from the centreline).
The disk is supported on a photo/video "super clamp", which has a ¼"/20 threaded hole in the bottom, so it can go on a tripod. The disk stands off vertical, but it's easy to compensate by tilting the tripod head.
There's a tendency for the rod to rotate (specially with an earlier version which used a brass rod). To help combat this, I cut slits in the trailing edge of the disk and pushed hook-and-loop straps through to support the mic cables; this tends to keep the mics pointing forwards.
One nice thing about this setup is that it packs completely flat. Take off the mics, pull out the rod, and you have a disc and a dowel to transport — easy!
While still in lockdown testing opportunities were limited. However I was lucky enough to have some trees outside the kitchen window, which attract a good number of birds. So, to test the quarantine disk, I attached it to the end of a tripod, along with an ORTF blimp containing two MKH 8040s.
The quarantine disk mics in this case were Comica CVM-V02O lavs; these are low quality and quite noisy, nowhere near a match for the Sennheisers, but they work to show the stereo effect. (I have since switched to Clippy XLR EM172s.)
Here are 2-minute excerpts from the recording. These excerpts were recorded exactly in parallel, so you can compare like for like.
ORTF Dawn Chorus |
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The dawn chorus in Inverness, recorded out the window, using two
MKH 8040s in ORTF.
23 April 2020 |
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Jecklin Dawn Chorus |
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The exact same recording as above, but recorded with two cheap
miniature mics in a Jecklin disk.
23 April 2020 |
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The Quarantine Disk from the rear. |
The photography clamp used to hold the disk. Since the thread on the bottom is angled, the tripod head is tilted to compensate. |
The Quarantine Disk from the front. |
Jecklin Dawn 2 |
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The sounds of the night and dawn in Lochardil, Inverness,
captured out of the window of my flat. The sounds of the night
give way to the dawn chorus, and then the daytime bird life.
This was recorded with a pair of Clippy miniature mics on the Quarantine disk. 3 May 2020 |
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