Sonnox Oxford Restore - Manual (Page 22)

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“LF”, “MF”, “HF” – These three buttons set which frequency band the big rotary control will
operate over. LF = 20Hz to 160Hz. MF = 160Hz to 1280Hz. HF = 1280Hz to 20kHz.
“Hz”. The Frequency control in the centre is used to set the nominal frequency about which in
Auto mode the detection algorithms hunt for a peak in the peak profile. In Freeze mode it
determines the frequency of the removal filters. The frequency can be selected using the scribble
tab in units of 1Hz (normal), 0.01Hz (Fine adjust) and 0.0001Hz (extreme fine adjust).
Remove Section
“Comb” – Sets the removal filters to be a comb filter. Comb is best for auto mode, and for when
there are many harmonics in a buzz.
“Para-EQ” – Sets the removal filters to be a narrow notching parametric EQ. You may prefer
the sound of these filters when there are few harmonics. Also, it is probably best to select Para-
EQ to remove an HF whine; if the user selects the HF frequency band while in Comb mode a
small red indicator flashes on this button as a reminder.
“+Even” – When using the Para-EQ option, by default even harmonics are not notched out
because frequently they are not present. Enabling this control will notch out even harmonics.
“Range” – This sets the frequency above which there are no notches. This needs to be as low as
possible to avoid loss of MF and HF information, but high enough to take out all the harmonics
of a buzz. Range cannot be set lower than 10% above the fundamental.
“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.
“Atten” – Set this to the minimum attenuation that will make the hum or buzz inaudible.
Display Controls
“Display Mode” – This control switches between the following display modes:
- Instant FFT
- Averaged FFT