APE Balls

[Matt Nolan]

I made a couple of Acoustic Pressure Equaliser spheres for some Behringer B-5 SDCs (for use with the Omni capsules, naturally). They started life as some very inexpensive castors from Amazon which I drilled and bored out on my little lathe. There is a short part at the back which is a slightly wider diameter bore to accommodate the HPF/Pad switch, but the rest of the hollow is a nice snug fit around the mic and capsule body.

My question is, how critical is the alignment of the capsule to the sphere?

Should I endeavour to align the edge of the diaphragm with the limit of the sphere, the centre of the diaphragm with the limit of the sphere, somewhere between those two, or have it so that the grille is flush with the limit of the sphere and the diaphragm ends up recessed inside? Is it critical?

I'm thinking that I should try to align the diaphragm somehow. But I'm slightly concerned about the grille sticking out and perhaps causing some reflection issues. In the photos of Schoeps or B&K mics with APE balls on them, they tend to be flush with the grille.

Thanks,
Matt.

 

[kingkorg]

According to the patent the diaphragm should be flush with the sphere.

https://images.app.goo.gl/3os9fUBMTfVPcv2d6

However Neumann broke this rule already with 2nd generation of the capsules.

https://images.app.goo.gl/pFs4TWnQ6Btwj5yT9

You can disassemble the capsule and just get rid of the excess material. But that would leave the diaphragm vulnerable. This grille you have is less than ideal for off axis waves, and the diaphragm is deep under

This is what i did with basically same exact capsule.

https://groupdiy.com/index.php?action=dlattach;topic=73114.0;attach=69362;image