Our patented passive proximity sensor system creates an analog, clean bass beat without the common low-end amplification problems of noise, feedback or delay. It is designed to produce a tone in the 33-100 Hz range (very low). The 33 Hz (with a strong 99 Hz harmonic) was selected because it offers a strong supportive bass "thump" in any key- similar to a large marching band bass drum.

This was the basis for our 'proximity sensor system', which uses a tuned, magnetic sensor that is capable of producing a very low dominate pitch when approached by a ferrous transducer plate.

This eliminates common problems associated with the resonant surfaces used with microphone and piezo pickups by eliminating the wide range frequencies that are used with guitar style pickups. The PorchBoard can consistently produce a specific, rich, low-end thump without noise or feedback.