On June 12, 2022 at 9:46:30 AM, thet (parenthetical@...) wrote:
There is a debate on padding with polarising voltage vs > capacitance
addition. See page 96 of this: > bksv.com/media/doc/be1447.pdf
They show about +/- 2-3db > for a pretty wide range.
That graph is misleading. The voltages pictured are 28, 150, 250. Those values might be appropriate for a small diaphragm measurement capsule. Large-diaphragm capsules such as most people here would be using would collapse at any voltage higher than 70-80V. The actual range of polarization values you might actually use in practice ranges from about 20V to 70V, not 28-250.
Further, most large-diaphragm capsules vary in response by more than 2dB from one capsule to the next. As an example, Neumann¡¯s spec on the U87 Ai ($3200) is plus or minus 2dB (which is to say, a 4dB delta from one mic to the next).
Therefore it doesn¡¯t make sense to focus on a potential 2dB shift in a single capsule¡¯s performance when the second mic you build would by 2dB if not 4-6dB different anyway. (Cheap capsules from Ali Baba definitely differ by more than 2dB from one to the next.)
But more to the point, you are not likely to see even a 2dB delta when changing polarization voltage within the range of 30-60V, at least not in my testing.
¡ª
matt.
