Need advice on High Pass & batch edits

[stubbsonic]

I'm processing some files that somehow have a 9 Hz sine wave in them. So the first thing I need advice about is a cheap or free brick-wall (am I using that right?) high-pass AU that will just remove signal below say 15 Hz, and leave everything else alone.

While I'm at it, I have a bunch of stereo tracks that need to be trimmed in pairs. In other words, I have stereo_file_A and stereo_file_B and I need to zoom in, look at them, and trim the same amount from both A & B, fronts and ends, and do a fade out. I know I can do this in the sequence editor in DP but there are quite a few pairs of files, so I need to do a little automating (with QuicKeys, probably).

Would greatly appreciate any advice on either question.

[Phil O]

I don't know of any batch processors for this sort of thing, but if I were doing it in DP I would try MW EQ for the HP filter. I think the lowest you can go is 20 Hz (Could be wrong - I'm on my laptop and don't have DP handy right now), or you could try DC notch. You can select multiple soundbites and select "Apply Plugin" from the Audio menu. For all intestine porpoises - batch processing.

For fades, you can copy automation to a clipping window and simply drag to tracks (very quick).

Hope there's something here you can use.

Phil

[stubbsonic]

Thanks, Phil. I really appreciate the help.

[daniel.sneed]

Izotope Alloy2 has a *brickwall EQ*.
Strange feature to me, but may solve this strange question, though.

[mikehalloran]

You want to set it for 20 Hz or higher to catch any first order harmonic artifacts. I know you are looking for free but Izotope RX has a filter that you can set to listen to the sine and find all harmonics removing only those frequencies.

[stubbsonic]

Thanks for the suggestions.
Izotope Alloy 2 does look like a fantastic option, $130 at SW! But as this is a one-off issue, and I don't have a budget, I think I'll stick with the free or under $30 options (?).

I tried all the EQ's I have with a High-Pass section. MOTU's MW EQ did the best of what I own, using only the HP section only, with a slope of 36. It removed most of the low signal except for a little bit at the beginning and end of the sample. I think generally that will work ok, but wondered if there might be some trick to get it to process the whole sample equally.

I have some free Voxendo EQ's, but those seem to be marketed as adding some "color" which I'd like to avoid.

I also have Audacity which does include this EQ where you can draw the curve to a brick-wall shape. But I don't know what kind of destructive power that might have.

[stubbsonic]

A friend was suggesting I look at FFT-type EQ/Filters. I think Audacity has one.

[stubbsonic]

I see Alloy 2 can be used in demo mode unrestricted for 10 days.

Hmmm. which emoticon?

[stubbsonic]

You want to set it for 20 Hz or higher to catch any first order harmonic artifacts. I know you are looking for free but Izotope RX has a filter that you can set to listen to the sine and find all harmonics removing only those frequencies.

Good call. After a closer analysis, when I got rid of 9 Hz, the things I was seeing left over after MW EQ was 18 Hz. So there is some harmonic stuff there too. Will check out RX2. Thanks.