Alesis DEQ230D manual Applications, Comb filtering

Comb filtering

You'll understand how this effect process got its name once you see the way it looks when recreated on the DEQ230:

1.Follow the instructions for items 1 and 2 from Step 2.

2.Starting from the far left of Channel A, press every other [BAND SELECT] button and take those bands all the way down to -12 dB. Then select the unedited bands and boost them +6 dB. When you’re done, look at the LEDs on the DEQ230 and remember the “comb” analogy. The bands set to +6 dB are the “teeth” of the comb, and those set to –12 dB are the spaces between the teeth.

3.For an even more interesting effect, press the [LINK/EXIT] button to unlink the bands on Channel B from Channel A and create the exact opposite settings. In other words, take the “odd” bands on Channel B to +6 dB this time and the “even” bands to –12 dB. Be sure to toggle the [BYPASS] and [LINK/EXIT] buttons to get an idea of what is being done to the signal as it passes through the DEQ230.

4.Experiment with different sized "teeth" and "spaces." Put two adjacent frequencies down and the next one up, repeating the pattern. Try "broken" teeth (i.e., boosting some frequencies more than others)! Adjust which frequencies to emphasize/de- emphasize to suit the incoming audio.

Applications 4

Note: depending on the incoming audio, it may be necessary to reduce the gain on some bands to prevent clipping.

There are preset programs similar to the ones used in these examples. You may find it interesting to compare the results of the different settings used in program 08 ("Comb filter - 125 Hz") and program 14 ("Telephone").

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