#291 EQ APO HIGHPASS WITH NO ROLL OFF

[marxx]

I thought of a Highpass but without a roll off point
meaning if i was to highpass at 80hz idont want it to roll of at 20hz or 1hz
im wondering how is gonna sound without a roll off point
is this possible.? can u add another highpass option thats not gonna have a roll off.?
just straight highpass and up only no roll off

[Etienne Dechamps]

The term you're looking for is "brickwall filter" (so named because the frequency response looks like a brick wall).

Brickwall filters are computationally expensive to run and they also come with tradeoffs - for example, they have a much longer impulse response which means they can produce ringing artefacts (or even pre-echo artefacts, in the case of linear phase filters, not to mention delay).

I think it should be possible to use a brickwall filter in EAPO by generating a FIR impulse response (say, a sinc) and having EAPO convolve it, but honestly it's unclear why you'd want to do that. Normal filters are fine for most use cases, especially if stacked to steepen the roll-off.

[marxx]

well how can i try it in EQ APO.?

[Peter Verbeek]

By using Peace equalizer as this is the easiest way. It has Butterworth and Linkwitz-Riley high and low pass filters (built from the standard high/low pass filters of Equalizer APO). By selecting such as filter and setting a high order a brickwall filter can be created (see screenshot).