[Plush]

A really good discussion here and thank you to 0VU who has made a great post.

My comments earlier were aimed at encouraging the user to buy and examine a real Jecklin or Schneider disk. It is made with foam of a certain density and composition.
The inventor specified foam as the disk's material.
This is the "engineered" part of the build of the disk.

Those proposing to make a disk of styrofoam, for example, are on the totally wrong path. It might work, but it is surely going to turn out to be tonally improper.

I do not know if the Jecklin or Schneider disks are still under patent. That was not really my main point.

For posters like JEGG who have good experience building disks, I can certainly say that you have more experience in building them than I do.

On the matter of which omni to use, I'm sure that EQ'ing a flat omni will work in the disk as well. I don't buy the notion that anyone was "taught" to be a robot and add any EQ to omnis. What I can buy is that some engineers were told to add high freq. EQ to flat omnis if they sounded dull in the hall. (But that is separate from any Jecklin disk useage---the technique is not widely embraced.)

Likewise I do not buy the notion (above stated as fact) that off axis response is ragged or unpredictable. It is predictable across a wide variety of quality omni mics.

Experimenters and home builders/craftsman should be encouraged. However, before you build your own, check out the real thing and hold it in your hands.

I have tended to use the Schneider disk on smaller fixed ensembles. By fixed I mean groups sitting in one position. (string quartets, brass ensembles, piano quartets)