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Selective Bandwidth Ducking


fader8

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Pursuant to my previous tip on improving noise gate performance:

http://logicprohelp.com/viewtopic.php?t=17553

. . . a couple of people asked me if I'd write up how to do selective frequency bandwidth ducking to improve a signals presence in a busy mix. So I thought Christmas day would be a good time to write this up and create an example as I'm deliberately not doing any "real" work today!

 

So here's the typical problem. A bunch of noisy guitars driving along and you want to inject an acoustic guitar or vocal lead in there once in a while. But you can't get the track hot enough or eq'd enough to overcome the noisy guitars. Ducking the guitars with either automation or a sidechained compressor might be too noticable, so this trick allows you to just duck the specific frequency range that is masking your lead track. Here's how to do it:

 

Note: the attached LP8 example just uses some stock Apple Loops that everyone should have, (I hope).

 

1. This is a mix technique and we'll be assigning plugs to auxes, so make sure PDC is set to "All" in your preferences.

 

2. Assign your noisy guitar tracks to a bus. We'll use bus 10 as in my example.

 

3. Assign your lead track to your main outputs. Create a Send on this track to bus 11 and set its level to unity, (ctrl-click the send).. This will also create an aux in your mixer. Delete this aux.

 

4. Create 2 new aux channels. Assign both their inputs to Bus 10, and both their outputs to your main outs.

 

5. Don't put any plugs on the first aux. On the second aux, (from top to bottom) place a Linear Phase EQ, a Noise Gate, then a Gain plug.

 

6. Set the EQ up with a Lopass and a Hipass only, with steep 48dB/oct slopes. Leave the Q at .71.

 

7. Set the Noise Gate as follows.

Threshold & Reduction: -100dB

Attack, Hold & Release: 0mS

Hysteresis: -20dB

Lookahead: 20.000mS

Sidechain: Bus 11

 

8. Open the Gain plug and enable Phase Invert(s). Close the Gain plug.

 

 

Here's what's happening in my example. When the acoustic guitar plays, the gate opens up on the second aux track that has the flipped phase noisy guitar signal. With the EQ bypassed and the aux faders at unity, you'l hear none of the noisy guitars as they will cancel out. In my example, I want to hear more of the body of the acoustic guitar which is about 225 to 1300 Hz so that's what I've set the EQ to pass. So now everything below and above that band won't be canceled. If I drop the fader down on the second aux, then the signal isn't cancelled as much.

 

When the acoustic plays, the body of the guitar sound comes through the mix a bit more as I'm attenuating the noisy guitars just in that band and just while the acoustic is playing. So your guitars can keep driving along!

 

You have a lot of control as you can tweak the reversed aux's fader for the amount of ducking and tweak the lo and hi pass freq parameters on the EQ to tune the band that gets ducked.

 

Cool, eh?

 

PS, I know, the example session sounds a bit silly, but you get the point.

 

Edit: LP7 version posted further down the thread.

fader8-SelectiveDucker.logic.zip

Edited by fader8
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  • 4 weeks later...
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Hi,

 

I would like to use an audio track to trigger sidechain input from other FX audio units other than compressor.

 

Seems like only the compressor has sidechain input feature.

 

for example, I would like to use an Audio Track bussed to say Bus 4 to trigger sidechain input of EQ, EVOC, GAIN or any other type of audio unit other than compressor, however no sidechain input.

 

Anyone know a workaround for this?

 

Thanks!

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  • 1 month later...
The file names in the attached file have all been truncated [Modern Rock Gu#4DFD5.aiff]. I suppose I could just drag a few loops from the browser, but I'd like to hear the right ones. Any idea what the original loop names are?

 

Isn't that strange? I just DL'd the file to check it and it does play, although my bin is showing those funny names too. So I selected each and did a "Show in Finder" command"

 

Track 1: Funky Electric Guitar Riff 44.caf

 

Track 2: Modern Rock Dirty Guitar 10.aiff

 

Track 3: Modern Rock Dirty Guitar 20.aiff

 

Track 4: Modern Rock Clean Guitar 07.aiff

 

Sorry, hope that helps.

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  • 4 months later...

this is exactly what ive been thinking of for the track that ive been mixing! ive got some fairly distorted synths as well as a vocal, and the vocals kind of hitting some of the same frequencys as the the synth line,

 

rather than eqing out the frequencys i was hoping there was a way to sidechain the synths eq to enable it to duck the relevant frequencys when the vocal was present.

 

does this work in logic 7?

 

cheers!

 

:)

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hi there, thank's very much for posting this, it worked really well.

 

it would be amazing if anyone could clear a couple of little points for me though.

 

( im happy to read further into stuff, if anyone wants to point me into the general direction of stuff that would lay the foundation down for me to comprehend this. )

 

i guess the bits which arn't really clicking with me are ; the gate, ive never actually side chained the gate before, so in this example the gate is opening when the other signal come's through, ?

 

i kind of get the eq's acting in a reverse kind of way, by cutting frequency's your actually letting them through, and this is because of the phase cancelation, ? but when i get a track, and put an eq followed by a gain set to phase invert both the right and the left side, it doesn't react in the same reverse kind of way?

 

one of the things i dont get is why the signal is not being increased in volume when the gate is opened, ? as when this is happening both signals are still going through the whole process, ? i dont really understand why i can only hear the equalized signal coming through as both aux tracks are going to the outputs, ?

 

im going to end before i ramble too much!! any further help with this would be great, thanks all the same though.

 

:)

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i guess the bits which arn't really clicking with me are ; the gate, ive never actually side chained the gate before, so in this example the gate is opening when the other signal come's through, ?

brian,

It sounds like you have all the concepts down, but sometimes stuff like this needs some time to sink in. Then you wake up slapping yourself as the pieces fall into place.

 

Look at the signal flow step by step. Keep in mind the bus send from the acoustic guitar track is just for utility purposes, ie it's never actually heard in the mix, it only triggers the gate. Only when the gate is triggered so that audio passes, do the two aux channels get mixed together resulting in attenuation of the mid band.

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Dear Fader 8,

I just discovered this thread about a year late and am keen to check out your example but when I downloaded your example file LP8 can't find the files. You say they are Apple Loops; can you tell me what I'm doing wrong here?

 

many thanks for what looks like a great mix trick (maybe for sitting vocals in a track without them being too loud, but still nice and intelligible)

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  • 3 months later...

Well this is the coolest trick in the mixing book! Works beautifully to keep piano from masking male vocals. thanks.

 

One variant I just tried is to use the mutipressor on the aux track that has the inverted waveform instead of using the linear phase eq. Just solo one or two of the frequency bands in the mutipressor, set the crossovers accordingly and adjust levels for each band. Make sure no compression or expansion is happening.

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  • 1 year later...
The file names in the attached file have all been truncated [Modern Rock Gu#4DFD5.aiff]. I suppose I could just drag a few loops from the browser, but I'd like to hear the right ones. Any idea what the original loop names are?

 

Isn't that strange? I just DL'd the file to check it and it does play, although my bin is showing those funny names too. So I selected each and did a "Show in Finder" command"

 

Track 1: Funky Electric Guitar Riff 44.caf

 

Track 2: Modern Rock Dirty Guitar 10.aiff

 

Track 3: Modern Rock Dirty Guitar 20.aiff

 

Track 4: Modern Rock Clean Guitar 07.aiff

 

Sorry, hope that helps.

 

I have various "Modern Electric Guitar" and "Funky Electric Guitar" files in my loop browser but none that have exactly those names. So here the files in your song are all blank and will not show in Finder. I also have the names truncated.

 

Should those loops all be available in Logic 9?

 

EDIT: I've made this work by DLing your archived version a few posts back. But I'm still wondering if I'm missing some loops here. Or am I just a few loops short of a basement rave? :)

Edited by camillo jr
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Great trick, still waiting on a FFT version of it tho...would be great to have one track analyse the other through sidechain and then mixing it for ya...;-) But this will do great for now!

 

Only one problem (using L8): The phase cancellation only seems to work when PDC is set to Audio and Instruments. It works but the PDC on the auxes and busses gets totally messed up. Somehow if I set the PDC to ALL, the phase cancellation trick with the gain utility does not seem to work....Could this be a Logic 8 thing?

Thanks

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