Topic: SP-CMC-4 in extremely high SPL setting

[Topy44]

Hi everybody!

First of all, its great finding a forum dedicated to one of my favourite hobbies, concert taping. I have been doing so for many years now, with varying success.

My current setup:
Soundprofessionals SP-CMC-4 mics (both mics connected to a single stereo minijack)
Soundprofessionals "Dual Channel Microphone Preamplifier"
iRiver H340 running Rockbox as recording device

Unfortunately ever since i got it i have trouble with the preamp. If the battery is anything but brand new or if the volume is high, i immediately get bass distortion. My guess is the mics are just not getting enough power.

The problem is that i am visiting an EXTREMELY loud metal concert in just a few hours time that i really want to record. I have some parts and all the needed tools around though, so i might be able to build a quick hack of a battery box. I have also read about the 3-wire mod.

What would you guys recommend? Please answer fast, only about 4 hours left to find AND build something.

[Giant_Rick]

Maybe you want to lower the input volume of the iRiver and work with the preamp's volume..is it fixed or adjustable?

Perhaps you can work on the recording in a PC software.. you should be able to knock out the unwanted bas frequencies.

[Topy44]

The problem was never the preamp or the recorder, the problem was always the mic capsules overloading.

Anyway, i decided to cut the cables and hack up a quick 3-wire power supply as described elsewhere in the forum with whatever parts i could find, and:
The result is absolutely astounding!
I just recorded the loudest concert i have ever been to, and the recording is CRYSTAL CLEAR! Perfect! I also got a dream position - the soundguy let me put my pullover with the recorder on it on the siderack, about 2m high dead center in front of the stage - so the resulting recording is one of the best i have ever made. With gain set to 0db on the iRiver i got a perfectly reasonable recording level going straight into the line in from the 3-wire modded AT853.

I absolutely recommend the 3-wire mod to anyone using the SP-CMC-4 or similar mics.