User`s manual

Description of controls is as follows:

Comb Frequency: Specifies fundamental frequency in Hertz of comb filter. Notches are

generated at multiples, or harmonics, of this frequency.

NOTE: Comb Frequency changes whenever the System Bandwidth setting is

altered; if you change the System Bandwidth setting, you will need to readjust

the Comb Frequency for any Comb Filters selected.

Notch Limit: Specifies frequency in Hertz above which no notches are generated. Minimum

Notch Limit is 100 Hz, while maximum Notch Limit depends upon the System

Bandwidth setting. Notch Limit is adjustable in 50 Hz steps.

Notch Depth: Depth of notches that are generated. Notch Depth is adjustable from 10 dB to

60 dB in 1 dB steps.

Notch Harmonics: Specifies whether notches will be generated at All, Odd, or Even multiples, or

harmonics, of the Comb Frequency. If, for example, the Comb Frequency is

set to 60.000 Hz, then selecting All will generate notches at 60 Hz, 120 Hz,

180 Hz, 240 Hz, 300 Hz, etc. Selecting Odd will generate notches at 60 Hz,

180 Hz, 300 Hz, etc. Selecting Even will generate notches at 120 Hz, 240 Hz,

360 Hz etc.

Filter Active Button: Used to switch the filter in and out of the process without affecting the

operation of the other filters. Button LED is illuminated RED when the filter is

in the process, and is not illuminated (GRAY) when the filter is out of the

process.

NOTE: The Filter Active button is equivalent to, and linked with, the Active

button in the associated Filter block on the Master Control Panel.

OK Button: Use either this button or the “X” button at the upper right corner of the

window to exit the dialog and return to the Master Control panel.

Hint: A comb filter is adjusted in the following manner. Set the Notch Limit and Notch Depth to their

maximum positions; set notch harmonics to All. Next adjust the Comb Frequency to achieve

maximum hum removal; normally this will be in the vicinity of 60 or 50 Hz. (Analog recordings will

seldom be exactly 50 or 60 Hz due to tape speed errors.

Next, adjust the Notch Limit down in frequency until the hum is bearly heard, then increase it 100 Hz.

Adjust the Notch Depth up following the same procedure. Finally, select the Odd or Even if they do

not increase the hum level; otherwise, use All.