|
The red sure makes a statement! A jecklin disk draws enough looks as it is.
In theory, the size of the disk will affect the amount of separation between the channels, or more precisely the frequency cutoff at which attenuation of the opposite side will occur. Lower frequencies will be picked up by both mics. As the frequency rises above the critical point, there will be increasing separation in the channels. Diffraction will also occur depending on disk design and frequency. Jurg Jecklin's original design has separation starting between 200Hz and 1kHz, depending on who you listen to.
A larger disk will allow greater separation at lower frequencies. Jurg Jecklin described in his paper OSS technique which he considered "optimal" stereo signal. I believe he updated the design more recently with a slightly larger disk. "Optimal" in this case is trying to approximate the human head in a quasi-binaral configuration. The follow-on Schneider disk improves the binaural-ness by adding a central sphere. Optimal in other cases may not replicate a binaural arrangement, as most classical recording presents more of a super-stereo "pleasing" arrangement or even a down-right manipulated sound-stage.
In theory, a larger disk will also allow greater separation between the mics, with greater phase separation, which is something I am playing with. I recently calculated a nearly 60cm disk, but I don't want to end up with an Iso-Mike. Varying the disk orientation to the mics can also vary the separation from certain directions.
I still can't find a good reason to need greater than normal HF response mics in a Jecklin disk, unless we are discussing a purely diffuse sound field.
|