I bought several?
TSB2555 capsules and looking at the datasheet it says the operating voltage is 1-10V?
( ). Seems like a?
big range...any recommendations of what voltage to get the lowest self noise and highest?
SPL? Lowest noise matters most to me. Also can the TSB2555 be used in a Schoeps style circuit?
That capsule is an electret. It needs no polarizing voltage.
Regarding ¡°lowest self noise,¡± you might end up considering a larger capsule. Capsule self-noise is inversely proportional to active diaphragm area. Said another way, larger capsules have (or at least potentially have) lower noise than smaller capsules.
Another factor is capsule sensitivity. The higher the capsule¡¯s output level, the lower noise the microphone could have ¡ª because you¡¯ll need less preamp gain to get a usable signal level into the DAW. Preamps add noise (especially consumer-grade preamps, especially at high gain settings), but even at low gain they¡¯re amplifying both the signal and the noise from the mic. The higher the signal level from the mic, the less preamp gain you¡¯d need, which tends to result in a lower-noise track.
I¡¯m not sure I understand the need for low noise AND high SPL. I think that microphones built for high SPL can afford to be noisier, and in fact typically are noisier, because the mic¡¯s noise floor will be inaudible as compared to the very loud signal. In the case of condenser mics, the circuit can easily overload due to a high SPL transient ¡ª or, the downstream preamp could clip if the mic¡¯s output voltage is too high. There are several common solutions to that, such as putting a capacitive pad on the mic¡¯s input circuit, and/or attenuating the signal within the circuit to reduce the likelihood that the preamp clips. But most of those solutions effectively lower the signal-to-noise ratio of the mic. In other words: raising SPL capability also raises the mic¡¯s effective noise floor. You¡¯ve turned down the signal, but the mic¡¯s native noise floor stayed the same (hence: lower signal-to-noise ratio), and you need more preamp gain to hear the attenuated signal, so the preamp amplifies the mic¡¯s noise floor.
Audio design usually involves tradeoffs.?
The TSB2555 can be used in a Schoeps style circuit, although the full Schoeps circuit includes a DC multiplier that electret capsules do not need. The DC circuit in a Schoeps mic contains roughly 50% of the components of the circuit, so that¡¯s not a trivial thing. You wouldn¡¯t want to build a Schoeps circuit from a schematic if you¡¯re using the TSB-2555, because you¡¯d be doing twice as much work as needed.
Other people on this forum can point to PCBs for Schoeps-based *audio* circuits that more easily adapt to the TSB-2555. Or you could see buy MicParts S-25, which is a full mic kit with a Schoeps-derived audio circuit. (Full disclosure: I developed and sell that kit, so the previous sentence is an advertisement, not an impartial recommendation.)
But, as suggested above, if your goal is lowest possible noise, the TSB-2555 won¡¯t get you there. By way of comparison, the MicParts S-87 (a large-diaphragm mic kit with a full Schoeps circuit and a very high-output capsule) delivers 6-8dB higher output than typical electret Schoeps mics, with lower noise.?
Also, if you want highest possible SPL, the Schoeps circuit wouldn¡¯t be my first choice.
¡ª
matt.
