Sonnox Restore - Manual (Page 6)

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“Sharp/Q” – Adjusts the width or sharpness of the notches. When too sharp, the filters tend to
ring. When too wide, the filters take out too much of the audio around the harmonics. So
adjusting this is a matter of finding a suitable compromise.
Quick Start Guide for the Oxford DeBuzzer
1. Find the nominal frequency. Start with the Sensitivity at maximum, Range and Atten controls
at medium settings, and Sharp/Q relatively wide. Alt Mode off.
If it is a low frequency buzz you are looking to remove, then play the music through the plug-in
for a while and look at the FFT plot. It will give you an idea of any persistent low frequencies.
Then set the big central rotary control to that frequency, or click on the peak in the FFT plot to
do the same thing. If that is the right frequency, you will hear the hum disappear. If not, look at
the peak profile to see what is happening. If there is no discernable peak then you may be an
octave too high, so try going to half that frequency.
If it is a higher frequency, set to Freeze mode, just look for it in the FFT plot, and click on the
peak that is found.
2. Once the hum has disappeared, you then need to refine the removal process to make it remove
only the minimum necessary. To do this, click on Diff so you can hear what is being removed.
3. Next, adjust the Range (either using the control, or by dragging the green drag handle on the
graph) to bring it down to being just above the highest harmonic you want to remove.
4. Next, adjust the Sharp/Q control to be the best compromise between being too wide (too
much audio is heard with the hum) or too narrow (the filters ring too much).
5. Next, switch back to listening to Audio mode, and reduce the Atten control clockwise so that
the hum is just inaudible.
6. Next, adjust the Sensitivity control to be as low as possible (to cause least damage); simply
reduce the sensitivity from 100 until the hum or buzz becomes just audible, then increase slightly
until it disappears. Repeat this with Alt Mode on. Use the Mode which allows the Sensitivity to
be least.
7. Decide if you want to try using the parametric EQ to remove the hum. If so, you may need to
re-adjust the Sharp/Q, and set the Slope.