DIY M50 capsule

[k brown]

Was gonna try it myself but all my plumbing mesh discs have this weird residue build up on them... (kidding, kidding)

. . . for vintage tone

 

[k brown]

I just discovered that the backplate holes don't need to be sealed with epoxy, or other, to convert to omni.

Once the center terminal is unscrewed and the rear backplate and main backplate are separated, just remove the small washer/spacer, then put the two backplates together such that their holes don't line up; there is one position where none of the rear plate's holes will align with those in the main plate.

Thus, the holes in the rear backlate don't need to be glued shut, and if the washer is retained, the capsule can be harmlessly returned to cardioid, if so desired.

I have to amend this post to say that I seem to have discovered that all that needs doing to convert these capsules to omni is to remove a thin clear plastic washer from between the two backplates.

There are two washers in there (in my examples, at least) - a metal one and a clear plastic one; it seems that removing both of them does make it omni, but also results in an unpleasant boost at the top. Removing just the clear plastic one is enough to 'omni' it, but has a much better tonal balance.

Have two more arriving soon so I can verify this with 'unmolested' capsules just to make sure I'm interpreting this correctly. Seems quite surprising that only that thin spacer makes the difference between cardioid and omni, and appears to have nothing to do with how the holes in the two plates are aligned; the unaltered CM-63 capsules also have their plates aligned so that all the holes are 'blocked' (which, of course they're not because of the washers/spacers).

 

[k brown]

I have to amend this post to say that I seem to have discovered that all that needs doing to convert these capsules to omni is to remove a thin clear plastic washer from between the two backplates.

There are two washers in there (in my examples, at least) - a metal one and a clear plastic one; it seems that removing both of them does make it omni, but also results in an unpleasant boost at the top. Removing just the clear plastic one is enough to 'omni' it, but has a much better tonal balance.

Have two more arriving soon so I can verify this with 'unmolested' capsules just to make sure I'm interpreting this correctly. Seems quite surprising that only that thin spacer makes the difference between cardioid and omni, and appears to have nothing to do with how the holes in the two plates are aligned; the unaltered CM-63 capsules also have their plates aligned so that all the holes are 'blocked' (which, of course they're not because of the washers/spacers).

I amended this info on another thread, but neglected to do so on this one.

I get the best omni response from these CM-60s with the grilles removed, by leaving both stock spacers/washers (the clear plastic and the metal) in place between the backplates, cutting a 1/16-1/8" piece out of the diaphragm spacer, and sealing all the holes on the back of the backplate.

 

[Paul W]

I get the best omni response from these CM-60s with the grilles removed, by leaving both stock spacers/washers (the clear plastic and the metal) in place between the backplates, cutting a 1/16-1/8" piece out of the diaphragm spacer, and sealing all the holes on the back of the backplate.

Is the slot cut out of the spacer just to provide a small hole to slowly equalize pressure so that it doesn't act like a barometer at very low frequencies?

If so, does it matter much where that hole actually is? Could you leave the spacers alone, and cover all of the holes in the backplate, but leave a pinhole-sized hole in the cover of one of those holes?

 

[k brown]

The spacer ring that has a small piece cut out of it is the one between the diaphragm and the backplate; so in front of the backplate.

Nothing to do with the spacers/washers between the front half and back half of the backplate, or the holes in rear of the backplate.

I'm guessing the reason for the gap in the diaphragm spacer is to equalize pressure between the front and the back of the diaphragm.