HP filter slope

[pascual]

I couldn't find the right thread on this. But I have a question. When it comes to cutting low freq in the master channel to finish a mix, how steep should I set the high pass slope. Ableton offers me a 12db and a 48db per octave. I'm curious what's the general best practice (other than the classic Internet forum SA answer of 'use your ears').

Cheers,
B

[BertKoor]

Controversial whether to do this at all. We recently had a long thread about it. It's still on the first page of this subforum
viewtopic.php?t=583829

On individual channels that are not supposed to have any bass, 12dB/oct at 80Hz is sort of standard on analog mixing desks.

Steep slopes give ringing around the tilt freq and much more phase changes.

[legendCNCD]

Yeah use 12 or even 6 if needed AT ALL, the higher the Q the higher the phaseshift etc.

[CrystalWizard]

Sounds questionable unless you don't have the full mix.

[pascual]

Controversial whether to do this at all. We recently had a long thread about it. It's still on the first page of this subforum
viewtopic.php?t=583829

On individual channels that are not supposed to have any bass, 12dB/oct at 80Hz is sort of standard on analog mixing desks.

Steep slopes give ringing around the tilt freq and much more phase changes.

Very interesting. Thanks for the link. A lot of sense in the general contributions…. I’ll have to review some of my mixing techniques.

B.

[No_Use]

Yeah use 12 or even 6 if needed AT ALL, the higher the Q the higher the phaseshift etc.

Does phase shift matter when using on the master bus?
Wouldn't think so.

[BertKoor]

Yes, phase shifts are exactly what causes peaks to appear and stick out while the overall volume remained the same. Especially during mastering, that's not what you want.

[BertKoor]

Here's a simple example that illustrates the issue.

Lets start with an ideal square wave. It consists of a horizontal line, halve the time at +1 and the other halve at -1.

You know what a square wave is, right? It's the sum if several sine waves, each at multiple frequencies.

Now take the lowest sine within the square wave. Shift it's phase. You probably cannot tell much difference by ear, its volume remained equal, but on the scope you see the waveform is altered dramatically. No more flat line, the peak is higher.

A square wave is only square because of the phase relation between the sines that it contains.

[No_Use]

Here's a simple example that illustrates the issue.
(...)

Good explaination, thanks.

[Unaspected]

Here's a simple example that illustrates the issue.

Lets start with an ideal square wave. It consists of a horizontal line, halve the time at +1 and the other halve at -1.

You know what a square wave is, right? It's the sum if several sine waves, each at multiple frequencies.

Now take the lowest sine within the square wave. Shift it's phase. You probably cannot tell much difference by ear, its volume remained equal, but on the scope you see the waveform is altered dramatically. No more flat line, the peak is higher.

A square wave is only square because of the phase relation between the sines that it contains.

That's a beautiful explanation.

[Propellerhands]

Another dumb question, so for example in ProQ3, if I used it on individual instruments, what slope should I used to cut low frequency from pads? Most of my cuts are at least 48db right now. And sometimes I use two instances of ProQ3.. because reasons. Shouldn't I do that?

[legendCNCD]

Another dumb question, so for example in ProQ3, if I used it on individual instruments, what slope should I used to cut low frequency from pads? Most of my cuts are at least 48db right now. And sometimes I use two instances of ProQ3.. because reasons. Shouldn't I do that?

You can do what ever you want. Yet I would be as usual, comparing 1. Low shelf, 2. 24dB first. Either of them will work usually. Rarely use any higher if not really needed. Most of the time shelf works just fine, depending on the sound, either not always needed to do -15dB on it if it is one of the sounds that has to have some of the lowest end. Rarely but sometimes needed is a combination of these two

So yeah, do how it sounds more like it, and at first I would not reach for the steepest one at all..