MIKING A TRUMPET WITH A CLIP-ON MIC
If I used a wireless system, how would I wire your clip-on mic to a Sennheiser Evolution SK100 body pack transmitter?
A large part of the sound you get when close-miking a trumpet depends on the mic placement. A microphone position on-axis to the bell sounds very bright and edgy; off-axis placement sounds more mellow or natural. That's because the high frequencies radiate out of the bell in a narrow angle. It helps to experiment with mic placement to get a sound that you're happy with.
The Crown instrument clip-on mic intended for wireless use is the GLM-100E. The Sennheiser SK100 transmitter can be used with a Crown GLM-100E without modification, but with reduced battery life. You will need to solder a 3.5mm (1/8") stereo phone plug to the wires on the GLM-100E cable. Here is the wiring:
The red lead receives power from the transmitter. The white lead supplies high-level audio to the line input of the transmitter. The shield is ground.
With the unipolar power provided by the Sennheiser SK100 transmitter, the GLM-100E can handle 120 dB SPL. If the trumpet is louder than that, the mic will distort. The wired GLM-100 can handle 148 dB SPL, so it will definitely not distort when used close to a trumpet. I can't predict whether your trumpet will cause distortion in the GLM-100E connected to a Sennheiser transmitter without measuring the SPL of the trumpet close to the bell. Hopefully you can try it out and return it if it distorts.