This is a highly effective audio processor that features eight fixed frequency resonators in parallel. This device is not a filter bank in the strictest terms but it can be used like a filter bank to change the frequency response of an audio signal. With this module one can replicate the subtle nuances of cavities on hollow bodied instruments, or at the other extreme, mangle the response so much that the output sounds nothing like the input.

Each resonator is essentially a band pass filter. The frequency response of each filter operates in such a way as to let only a narrow band of frequencies through. The selectivity of each resonator can be controlled by a front panel pot. At its highest settings the resonator will ring at its selected frequency.

You can think of each resonator as being analogous to a bottle. When you blow air over a bottle it resonates and a note is heard. Fill the bottle up with water and the note changes. The Oakley Octal Resonator is eight such bottles, each with a different level of water in it.

You can't change the frequency of each resonator but you can change the depth of the affect each resonator has on the sound. Each pot controls the Q or resonance of the filter. With all the pots fully off, there is little sound from the unit. Turning up each pot will accentuate that particular frequency.

The resonant frequencies are approximately: 250Hz, 350Hz, 500Hz, 700Hz, 1000Hz, 1400Hz, 2000Hz, 2800Hz.

The Octal Resonator has three outputs. The first output is a combination of all eight resonators. This can be used on its own or perhaps mixed with the original signal with a suitable mixer. The Oakley MultiMix is an ideal companion because you can not only add to the resonators' outputs, but also subtract.

The other two outputs take the outputs of the left and right hand sides of the resonator module. That is, the 250Hz, 500Hz, 1000Hz and 2000Hz, come out of the 'left out' socket. And the 350Hz, 700Hz, 1400Hz and 2800Hz resonators come out of the 'right out' socket. You can use these two outputs to generate unusual stereo effects.