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High pass filter

Postby twotoedsloth » Wed Apr 07, 2021 6:55 pm

Hello kind folks.

Quick question: how high should i set my highpass filter for recording unaccompanied classical guitar in a very good acoustic space (425 seat auditorium)

Many thanks
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Re: High pass filter

Postby Sam Spoons » Wed Apr 07, 2021 7:03 pm

I'd start at the lowest setting, say 20Hz* and adjust it upwards until you hear it's affect then back it off a little. But I wouldn't apply it to the recording unless it is a live performance recording and the mic is also feeding a PA, I would record full bandwidth and process later in the computer. If you print the HPF to 'tape' you're stuck with it for good or otherwise.

* Acoustic guitar in standard tuning has a lowest (bottom E) fundamental of 80Hz but the guitar body and the recording space will have resonances below that, whether you want to remove them or not is a creative decision and depend on the style of playing (Flamenco, for example, will involve percussive elements which will definitely extend below 80Hz).
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Re: High pass filter

Postby Hugh Robjohns » Thu Apr 08, 2021 3:49 pm

twotoedsloth wrote:...how high should i set my highpass filter for recording unaccompanied classical guitar in a very good acoustic space (425 seat auditorium)

I wouldn't use one at all, by preference. The only time I'd consider one in the kind of situation you describe is if the room had problems with infrasound (tube trains running underneath, a major road with traffic lights outside the building, etc), or unwanted air currents causing low rumbles...

And even then, if you're using directional mics the chances are their natural roll off will deal with most of it anyway. Using omnis might make a high-pass filter more necessary, but unless it was obvious that VLF was causing problems with the recording levels I would leave an HPF decisions to the editing/mastering stages.
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