k brown
Well-known member
Though this stuff would seem more logically to belong in this thread:
https://groupdiy.com/threads/takstar-cm-60-suggested-mods-improvements.84885/
that one has become almost exclusively about circuit mods, so I didn't want to derail that one with this info.
The electronics in the CM-60 and CM-63 seem just fine for my purposes, as I don't do close mic'ing of loud instruments, so don't need the FET bias tweaking to maximize SPL handling, and their self noise, while higher than my other mics, has yet to be audible in actual use during a recording.
Initially spurred on by @kingkorg experiments in this thread:
https://groupdiy.com/threads/diy-m50-capsule.73114/
I was more interested in how the sound of these capsules could be improved, and also converting them to omnidirectional.
The biggest single improvement to the CM-60 capsule is to shave off as much of the front of the capsule as possible, leaving just enough material to securely hold the contents in place. This is what kingkorg did in his mod to make an M50-type mic. The diaphragm is just too recessed behind the front of the grille. The capsule is disassembled (leaving the two halves of the backplate attached), the front removed (I used a razor saw; crude, but effective - followed by some filing) leaving a thin retaining lip, and the stock mesh replaced with a suitable size of stainless steel mesh disc from a plumbing supply, which is more robust than the stock mesh for better protection.
To further convert this to an omni, simply plug the holes in the rear backplate - kk used epoxy; I used Coax-Seal black mastic, so that I can return them to cards if I choose. kk also removed all the spacers between the backplates, but for me that resulted in a sound that was too bright. I later found that leaving in only one metal spacer (and not plugging the holes), still results in an omni, but has a more usable top end (I'm awaiting another pair of '60s to double-check this on, so I have an unmodded one to compare; this could suggest that balancing the top end of these capsules could additionally be done by how many, if any, spacers are used - stay tuned).
I actually like this omni a bit better than my Oktava MK-012 omni capsule, which has a bit of a heavy, somewhat blurred bottom. These compare quite well with the Rode NT45-O!
_________
The unpleasant top end of the CM-63 capsule is also due almost entirely to the front grill. The nasty peak at 7-8kHz seems clearly to be the result of too much material in front of the diaphragm; in the '63's case it's not because the diaphragm is too recessed, as in the '60. By enlarging the outer-ring holes to 3/32", and lengthening every other slot to the bottom of it's bevel, then restoring the bevel, the top boost becomes more even. It's still rather bright for close mic'ing, but because it's more even it can be EQ'd more effectively.
For distant / Classical mic'ing in or near the diffuse field, the top lift is just about right; my reference for that is my Okatva MK-012 cardioids, which have always delivered a tonal balance that's just right in most such cases.
The other thing i like doing with these is plugging just one or two of the rear backplate holes with Blu-Tak or Coax-Seal which nudges the pattern towards subcardioid and warms their sounds a bit (any SDC cardioid, actually).
If the '63's front grill is removed completely (and just plumbing screen in front), the response is quite flat and suitable for close mic'ing.
https://groupdiy.com/threads/takstar-cm-60-suggested-mods-improvements.84885/
that one has become almost exclusively about circuit mods, so I didn't want to derail that one with this info.
The electronics in the CM-60 and CM-63 seem just fine for my purposes, as I don't do close mic'ing of loud instruments, so don't need the FET bias tweaking to maximize SPL handling, and their self noise, while higher than my other mics, has yet to be audible in actual use during a recording.
Initially spurred on by @kingkorg experiments in this thread:
https://groupdiy.com/threads/diy-m50-capsule.73114/
I was more interested in how the sound of these capsules could be improved, and also converting them to omnidirectional.
The biggest single improvement to the CM-60 capsule is to shave off as much of the front of the capsule as possible, leaving just enough material to securely hold the contents in place. This is what kingkorg did in his mod to make an M50-type mic. The diaphragm is just too recessed behind the front of the grille. The capsule is disassembled (leaving the two halves of the backplate attached), the front removed (I used a razor saw; crude, but effective - followed by some filing) leaving a thin retaining lip, and the stock mesh replaced with a suitable size of stainless steel mesh disc from a plumbing supply, which is more robust than the stock mesh for better protection.
To further convert this to an omni, simply plug the holes in the rear backplate - kk used epoxy; I used Coax-Seal black mastic, so that I can return them to cards if I choose. kk also removed all the spacers between the backplates, but for me that resulted in a sound that was too bright. I later found that leaving in only one metal spacer (and not plugging the holes), still results in an omni, but has a more usable top end (I'm awaiting another pair of '60s to double-check this on, so I have an unmodded one to compare; this could suggest that balancing the top end of these capsules could additionally be done by how many, if any, spacers are used - stay tuned).
I actually like this omni a bit better than my Oktava MK-012 omni capsule, which has a bit of a heavy, somewhat blurred bottom. These compare quite well with the Rode NT45-O!
_________
The unpleasant top end of the CM-63 capsule is also due almost entirely to the front grill. The nasty peak at 7-8kHz seems clearly to be the result of too much material in front of the diaphragm; in the '63's case it's not because the diaphragm is too recessed, as in the '60. By enlarging the outer-ring holes to 3/32", and lengthening every other slot to the bottom of it's bevel, then restoring the bevel, the top boost becomes more even. It's still rather bright for close mic'ing, but because it's more even it can be EQ'd more effectively.
For distant / Classical mic'ing in or near the diffuse field, the top lift is just about right; my reference for that is my Okatva MK-012 cardioids, which have always delivered a tonal balance that's just right in most such cases.
The other thing i like doing with these is plugging just one or two of the rear backplate holes with Blu-Tak or Coax-Seal which nudges the pattern towards subcardioid and warms their sounds a bit (any SDC cardioid, actually).
If the '63's front grill is removed completely (and just plumbing screen in front), the response is quite flat and suitable for close mic'ing.
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