Recording in Stereo

After my first series of recordings, I realized that my next step would have to be constructing a better means of recording in order to capture a better quality of sound and hopefully have more more control over the sounds that I am capturing.

I bought a Behringer 5-Input 2-Bus Mixer with XENYX Mic Preamp and British Eq despite the warnings of never connecting the piezo mics to an AC powered amp. This amplifier/mixing board would allow me to capture a wider range of sounds and also to isolate sounds using the Trim, EQ and Level functions on the mixing board. I also ordered a package of new piezo discs off the internet with varying frequencies (the larger the disc, the lower the frequency).

Secondly, with my growing knowledge of how recording and microphones and specifically, contact microphones worked, I created a way to record in Stereo format using contact microphones.

I used 2 Piezo discs, the first (left) is .6KHZ/44mm, the second (right) is 6.5KHZ/20mm. They are each wired to their own 22 gauge strand of the shielded audio cable and they share the ground wire. Then each opposing end of the strands and the ground wire are soldered to the appropriate components of the 1/4" stereo input plug.

By using 2 very different frequencies in each mic, the range of sound that is captured is very wide and it should make it easier and more accurate when I try to isolate certain frequencies.

This recording is from 5 points of my engine
1. Engine
2. Air Intake
3. Hot
4. Rotator Belt
5. Shock

The clip is another 30 second sample from the original and the tracks are played simultaneously.
Again the rhythm of each track is slightly different but if you try to listen to individual sounds it is interesting to follow the poly-temporal scale of each recording in relation to the others.