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Old 31st May 2003
Gear Maniac

Originally posted by Dave Derr

Let me ask a question about Highpass (or Lowcut) Filters.

1) If you had to pick 4 -5 low cut frequencies... what would they be?

IE. 40 Hz, 80 Hz, 100 Hz, 160 Hz, 270Hz Low cut

2) Give us one thing you love having Low cut filters for?
No way, very bad idea. Filters MUST be variable from 30hz !!!

Variable roll off rate from 6db/ove-36dB/ove

Additional function on the hi pass. A Gain boosting function locked to the cutoff frequency. This Gain Parameter has should have variable Gain from 1-12dB. This is differnt to using the Q, Res or Emphasis parameters on filters in synths which have a very narrow bandwidth .

When i sweep basses with a hi pass i often still want to retain as much hi freq content as possible so that when closing the filter the frequencies around the cutoff are boosted by a selectable amount but with a much wider bandwidth than the typical narrow bandwidth Q,Res, Emphasis synth filter parameters. Of course this defies the nature of hi pass filtering. In effect i guess the situation makes use of 2 different filters effecting the one signal but in different ways. The first filter the hi pass has a variable cut off freq and roll off rate. The second filter is a shelving nature with variable boost and locked to the same cut off frequency in the first filter.

I simulate this in a synth in the following way.

When assigning cut off frequency of a 24dB/ove roll off rate Hi-Pass (with 50 % resonance) to the modwheel on an EMU sampler, I notice on many sounds the top end gets gritty an raspy when sweeping the cut off while the signal is getting boosting by 4-6 dB of gain also assigned to and controlled by the modwheel.

Id like the EQ/Filter box to be Non transparent sounding.