MIKING A TRUMPET WITH A CLIP-ON MIC
I recently did a gig where a trombone collegue of mine used a Crown clip-on microphone. I was well impressed with the sound quality as the majority of trombone type mics are not so good. I myself am a pro trumpet player and have just about given up using clip-on mics as the sound is inferior (I tested pretty much everything there is. So I am using a large-diaphragm condenser mic at the moment. However for some shows I could use a clip-on mic but don´t want the bad sound associated with them. Do you think your clip-on mics would be up to miking a very loud lead trumpet?

If I used a wireless system, how would I wire your clip-on mic to a Sennheiser Evolution SK100 body pack transmitter?
Nigel Moore

 
Reply: A Crown GLM-100 clip mic can handle 148 dB SPL, so it should be able to handle a trumpet without distortion. I recommend the GLM-100 omnidirectional mic over the GLM-200 hypercardioid mic because the GLM-100 sounds more natural, has a flatter frequency response, and has much less handling noise. Also, the GLM-100 can accept higher sound levels without distortion. P.A. feedback is not a problem with the GLM-100 because the mic is so close to the trumpet, and the trumpet is very loud.

Crown GLM microphones data sheet

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:
Tip: GLM-100E cable red lead.
Ring: GLM-100E cable white lead. Change the line-level pad in the transmitter to 0 dB.
Sleeve: GLM-100E cable shield.
The mic might start distorting as battery power drops, and a fresh set of batteries should fix the problem.

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.