Help with sidechain compression?

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Pioneer
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Help with sidechain compression?

Post by Pioneer » Fri Feb 15, 2013 8:05 pm

I watched 2 tutorials on sidechain compression and usually I figure out everything pretty fast. For some reason, I do not think I am doing this right.

standard setup where the kick is the input. I have an instance of kicker going to the out. I also have it going into a compressor also going into the out. the compressor is set so the threshold is lower than the kick waveform.

I then took synths and sent them into the compressor....there is no real difference at all...that is what is weird.


If I bypass the compressor, the kick is twice as loud since it is routed to the out twice. If I delete the connection from the kick that goes straigh ou and have the compressor on, I get no sound. Is this because the kick is the trigger or because I screwed something up?

thanks!

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samrai katt kovboy
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Re: Help with sidechain compression?

Post by samrai katt kovboy » Fri Feb 15, 2013 8:25 pm

dont totally understand what you mean with the two kicks...
but anyway-
first put the module/synth you want side chained and connect into compressor-
then connect the kick ( or other module )
and program the kick where you want the side chain to occur, make sure that the threshold is sensitive enough...
and in the compressor you have the option of side chaining and here you have to choose the kick as the input,
and i think this is where you went wrong.
Then connect the compressor to output.
Hope that helps?

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SolarLune
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Re: Help with sidechain compression?

Post by SolarLune » Fri Feb 15, 2013 11:34 pm

Like Samurai said, set the sidechain input on the compressor to be the kicker. If you leave it at default, the compressor will just compress the entire signal sent into it (useful if you want to boost quiet sounds at the detriment of the peaks and higher volume sounds in your mix).

Pioneer
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Re: Help with sidechain compression?

Post by Pioneer » Sat Feb 16, 2013 1:21 am

thanks guys. I have the Kicker set as the sidechain input, so that is why I am confused.

I will mess with it again in a bit and see if there is something else I am doing wrong.

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The Handle
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Re: Help with sidechain compression?

Post by The Handle » Thu Mar 28, 2013 7:53 pm

samrai katt kovboy wrote:and i think this is where you went wrong.
Then connect the compressor to output.
Pioneer wrote:I have an instance of kicker going to the out. I also have it going into a compressor also going into the out.
He already stated that the compressor is connected to the out module, and the volume doubled when he bypassed it, so the compressor=>out connection sounds fine.

If you're still having issues (I know this was posted a while ago), it sounds to me like you have to check some settings. Read through the explanation of each setting below so you get a more thorough understanding of them, then start troubleshooting. My guess is it's probably your slope and/or your attack/release values. It could be several other things too (see bottom for troubleshooting after reading about the settings).

**EXPLANATION OF COMPRESSOR SETTINGS:**

--Slope--
This controls the amount the compressor reduces the volume when activated (the threshold is the point where the compressor is activated).
In SunVox it is measured by a percentage, but in other DAWs it is called "Ratio". They have the same effect, it's just that the measurement is different (Example: 50% vs 2:1 ratio)

For example:
I have a kick and a synth going to a compressor. I set the sidechain input to the kick module, so when the kick's volume goes over the threshold, the sidechain compressor activates and decreases the volume of the synth.

Now let's get into some numbers.
Suppose the slope is set to 50%. If my kick goes 2 decibels over the threshold, the compressor will reduce the volume of the synth by 1 decibel (2*.5=1). If my kick goes 4 decibels over the threshold, the compressor will reduce the volume of the synth by 2 decibels (4*.5=2). If I want less volume reduction, I reduce the slope. So now let's set that slope to 25%. If my kick goes 4 decibels over the threshold, the compressor will reduce the volume of the synth by 1 decibel (4*.25=1).

--Attack--
This value controls how long the compressor takes to reduce the audio when activated. Note that (when activated) the compressor will IMMEDIATELY start to reduce the volume. It's the attack that tells it how long to take to get to the full reduction.

Suppose I have a kick that lasts 32 milliseconds and exceeds the threshold by 4 decibels. My slope is set to 50%, and the attack time is 10 milliseconds. The volume of the synth connected to the compressor will be reduced by 2 decibels (4*.5=2) over 10 milliseconds. The biggest change in volume will be at the end of the attack.

Here is a more visual example of the effect of the compressor on the synth:

--- = Volume of synth
Threshold = 2 db

Assuming the synth's volume starts at 8 decibels:
A-------- <==(kicker exceeds the 2 db threshold by 4 db, sidechain compressor is activated and begins reducing the volume of the synth)
B------ <==(the synth's audio is reduced by 2 db 10 milliseconds after being activated at A. The volume of the synth is now 6 db)

Note that the length of the kick doesn't matter (when changing the volume), its volume just needs to exceed the threshold to activate the compressor (you could have a kick that is 1 millisecond long and it'll still activate it). To sustain the compression, your kick will have to stay over the threshold for a longer period of time.

--Release--
This controls how long the compressor takes to return the audio to its original volume after the attack (it's essentially the same as attack, but backwards).

Using the example above (from the attack portion of this post), let's set the release to 45 milliseconds. After the sidechain input audio stops being over the threshold, the release returns the synth to its original volume over 45 milliseconds.

VISUAL EXAMPLE:

--- = Volume of synth
Threshold = 2 db

Assuming the synth starts at a volume of 8 decibels:
A-------- <==(kicker exceeds the 2 db threshold by 4 db, sidechain compressor is activated and begins reducing the volume of the synth)
B------ <==(the synth's audio is reduced by 2 db 10 milliseconds after being activated at A. The volume of the synth is now 6 db)
C-------<==(the kick's volume has decreased and is no longer over the compressor's threshold, which triggers the release)
D-------- <==(45 milliseconds AFTER C, the audio is back to its original volume)


What your attack/release/slope values are depends on what you want. If you want a hard, pumping sidechain compressor, try an attack of 10 and a release of 45, then adjust the slope until it really pushes the synth down (just before it hits the bottom of the waveform box). This will reduce the volume over 10 milliseconds, then return it to its original state 45 milliseconds after the sidechain input audio stops being over the threshold.

If you want the kick to be louder, but don't want it to affect the compressor, you can link it to a distortion module (which is linked to out) and increase the volume (of the distortion module). The sidechain just uses the input you give it. The sidechain compressor functions the same as a regular compressor, the only difference is that the sidechain asks for an input instead of affecting everything linked to it.


**TROUBLESHOOTING:**
The first thing you should check is if there is any audio being played. If there is no audio...well...there's no audio. ;)

You didn't hear the kick when you disconnected it from out because the sidechain compressor doesn't let the input audio pass. The kick will still affect the compressor, you just won't hear it. Did you make sure you linked the synths to the compressor correctly? If the compressor is going to the synths, you won't hear them. I would start by reconnecting everything just in case.

Your linkage should look like this:
kick=>compressor (set kick module to input)
kick=>out
synths=>compressor
compressor=>out

If you're still having a problem after reconnecting everything, it could also be that your kick is too quiet or your slope is too low. If you're using the kick module with its default volume, you probably need to either increase its volume or increase the slope of the compressor (either one will affect the change in volume from the sidechain. You can do both too). You can link the kick to a distortion module, link the distortion module to the compressor, unlink the kick (the module itself) from the compressor, then increase the distortion module's volume and set it as the input instead.

So now your linkage should look like this:
kick=>distortion=>compressor
kick=>out (or you can link the same distortion module to out if you need a volume increase on the kick's out volume [kick=>distortion=>out])
synths=>compressor
compressor=>out

Depending on what your attack/release times are, you might have to adjust those as well (if the attack is too long it can be hard to hear/see a change).

If you're still having problems after that, I don't know if I can help you. I'd either need a screenshot of the project or you'd have to ask Nightradio if it's a bug and send him the project file. You were able to hear the kick, so I don't think it's a hardware/audio-settings issue

**QUICK SUMMARY:**
-Threshold is the volume where the compressor is activated. The length of the input audio doesn't matter, it just has to exceed the threshold.
-The amount of volume above the threshold is what determines the effect of the slope (this is why hard limiters are handy, they limit the volume instead of reducing it temporarily)
-The attack controls how long it takes to get to full volume reduction (after activation)
-The release controls how long it takes to get back to original volume (after the sidechain input audio stops being over the threshold)
-Reconnect everything to ensure the modules are linked correctly
-Check the sidechain input's volume or the sidechain's slope
-Check attack/release times
-If all else fails, ask Nightradio
Last edited by The Handle on Fri Sep 13, 2013 10:37 am, edited 2 times in total.

nopcorp
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Re: Help with sidechain compression?

Post by nopcorp » Tue Sep 10, 2013 8:13 am

I can't believe I just found this great tutorial. Thanks to, The Handle. Very useful info

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alien_brain
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Re: Help with sidechain compression?

Post by alien_brain » Tue Dec 10, 2013 2:00 am

a typical studio technique used to make kick and bass fit well together is to side chain the kick to the bass. doing this you can 'scoop out' sonic territory momentarily from the bass channel so the kick just fits and doesnt interfere with bass frequencies. this way you can minimize phase issues between the two channels (although any good engineer will check the phase of bass and percussive sounds against the mix) and avoid peaks that would normally result and require additional dynamics treatment. part of the beauty of this technique is that you can set the appropriate sonic depth of the effect to where you get a good balance of bass to kick. it doesnt need to be an extreme 'gate' effect for the technique to work well. you can set envelopes and levels such that when layered, you cant tell that anything is being done, it just sounds natural with much improved definition. the style of severely pumping a mix with a kick as in some house music grew out of this technique imo.

actually, you can 'make space' using this method for any layer(s) in a mix. theres even a way to apply the technique to specific frequency bands! you can scoop out room for a vocal or lead synth this way. anybody have a vocoder? betcha didnt know they could be used for that!

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