User Manual

OB-6 Operation Manual

Filter

Frequency: Sets the lter’s cutoff frequency. In Low-Pass mode,

frequencies are reduced from the top down — cutting the high frequen-

cies and passing the low, hence the name “low-pass.” In High-Pass mode,

frequencies are reduced from the bottom up — cutting the low frequen-

cies and passing the high, hence the name “high-pass.” In Notch mode,

frequencies are removed in a notch centered around the cutoff frequency.

In Bandpass mode, a band of frequencies are passed through the lter

centered around the cutoff frequency — while frequencies on either side

of that band are removed.

Resonance: Emphasizes a narrow band of frequencies around the cutoff

frequency. Unlike low-pass lters on some synthesizers, the OB-6 Low-

Pass lter does not self oscillate. This is faithful to the original Oberheim

SEM design.

High levels of resonance can sometimes cause the OB-6 outputs to clip if

its sound generators are also set to high output in the Mixer. Monitor your outputs

carefully to ensure optimal, clean signal levels. If you experience signal clipping, try

reducing the levels of the oscillators in the miXer section, the amount parameter in the

Loudness Envelope, or the resonance parameter in the lter.

Track: off, half, full—Sets the amount of modulation from the keyboard

to the lter’s cutoff frequency. Selecting

half or full means that the

higher the note played on the keyboard, the more the lter opens. This

is useful for adding brightness to a sound as higher notes are played, which

is typically how acoustic instruments behave. If both half and full are off,

keyboard lter tracking is off, meaning that lter frequency is unaffected by

playing higher or lower notes on the keyboard.