HOW DOES SIDE-CHAINING ACTUALLY WORK?

Cubase
1

Fellow Cubase :nerd: users and :ugeek: experts…

I just realised, again, that I do not really understand side-chaining, let alone it’s creative
potential.

I have many questions on that I suppose, but, “one step at a time”. (Less than 2yrs ago I didn’t know what and where a “C” on a keybord was, let alone WHAT a DAW or a Hi-hat was!!!

So, take it “slowly”…

:question: I suppose my “MAIN-question” would be, “how does the signal-flow work” when “activating” and “de-activating” a plug-in’s sidechain function? (Is there a graphical representation of it on the Net? I couldn’t find any.)

Let’s use the single-band compressor as an example…

I do understand, basically, what the compressor does. (It reduces dynamics - the difference between the peaks and the softer parts.)

OK, so here’s the scenario:

I send an instrument to a Group/FX channel and insert a compressor. I can see the compressor doing its job - “GR” - “Gain Reduction”.

:astonished: But as soon as I activate the side-chain button on the compressor the volume increases dramatically and the compressor ceases to do GR!

:open_mouth: Furthermore, if I set (for example) a maximum 8/1 GR-Ratio and start reducing the threshold the volume increases even more!

…So, why!?

…I do understand that if I send another instrument to the side-chain, that that instrument will
trigger the compression-action.

I know, I’m just scratching the surfuce here, barely.

… Feel free to elaborate on other uses thoug/aspects though.

Thank you for taking the TiME and INTEREST to teach!

2

We are talking the stock Cubase compressor here!

Have you got the Auto button enabled under Make up? as that will raise the output to compensate for any (supposed) gain reduction automatically!

Of course if you activate the side chain and don’t feed the sidechain with a signal you will get no gain reduction happening! The compression signal is derived from the side chain signal, normally fed from the input but when you activate the sidechain function it breaks the normal routing and now looks for a signal down the sidechain input.

3

ftp://sonic-core.net/manuals/SCOPE/Manual/english/Chapters/Studio/Vinco.pdf
http://www.moultonlabs.com/more/principles_of_multitrack_mixing_the_kick_drum_bass_relationship/P3/

found within 1 minute… They call it Google or something like that amazing thing…

Because the “detection circuit” which determines the signal, which the threshold refers to is switched to the external sidechain input. If you don´t have any signal coming to the external sidechain input, the compressor has no reference signal anymor, which is the audio siganl itself, as long as not switched to external sidechain input.

Because you probably have auto makeup gain enabled - disable it.

4

Basically, what sidechaining does is this:

Normally, a compressor analyses the incoming sound, and based on the peaks it measures, it applies compression to the signal. When using sidechain, the compressor has 2 inputs. The normal input is the signal that will be compressed, but instead of analysing this signal to determine the compression, it measures the sidechain input to determine the compression behaviour. This lets you compress a signal not based on it’s own peaks, but on the peaks of another signal.

Easy application is for radio DJ’s. They sidechain their own microphone into a compressor compressing the music signal. This measn that when they talk, the music is compressed so you can hear the DJ more clearly. This behaviour is known as ducking, and is also used a lot in electronic music. They sidechain the kickdrum into the rest of the signal, to give the kickdrum more headroom.

So to use sidechaining, you have to insert the compressor on the signal you want to compress. Enable sidechaining on the compressor. Then you have to send another signal (the signal you want the compressor to analyse) to the sidechain input of the compressor. You can do this in Cubase by enabling a send on the audio track and when sidechaining on the compressor is enabled, this should be an available send destination.

Hope that helps :wink:

-edit- Thinkingcap was faster. :stuck_out_tongue:

5

As was Split… :mrgreen:

6

.<, getting punished for writing the most detailed reply :frowning: :smiley:

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Thank you Split, “Thinking Man” and Strophoid for the interest to assist and quick responses, I’ll chew on this for a bit and get back to you here!

“Cap Man”, I :mrgreen: envy you… :laughing:

8

Was meant in realtion to my “too slow” post…
Well, at least the one with the most words used… :mrgreen:

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It's not neccesarily peaks ... it can also be longer-term RMS value, depending on compressor used.
10

For a change :laughing:

11

Are we not the masters of nit picking :stuck_out_tongue:

I was going to point out that as well, the stock cubase compressor has a knob that changes the detection from RMS to Peak and anywhere in between.

12

OK you Guru’s :ugeek:

Once again, I :wink: appreciate your replies very much and I’ve learned and am still learning.

I now :sunglasses: understand better, that by activating the Side-chain (SC) that it stops looking for the “profile determining” signal down the “normal” input channel, but now looks for it down the “SC-channel”.

But, what I still :question: don’t understand (and maybe I don’t really understand your replies, …but may be I do), is why
is there a volume :exclamation: increase when the compressor (or any other side-chainable plug-in I suppose) does not get a “profile determining/reference” signal from the SC input!?

And, the volume :exclamation: increases even more when I set (for example) a maximum 8/1 GR-Ratio and start reducing the threshold volume!? (So by the way “Clever Man” with the “Crap-Cap”, the “Auto-Make” was engaged :wink: ).

:question: Why!? Why the volume increases?

Is it because the SC is a channel with volume and the compressor’s Threshold determines how much of the SC-volume is let through? (…Well, I hope you can see I’m :nerd: trying… :unamused: )

Thank you again!

13

Have you got the Auto button enabled under Make up? as that will raise the output to compensate for any (supposed) gain reduction automatically!

14

Split, yes, I did - “(So by the way “Clever Man” with the “Crap-Cap”, the “Auto-Make” was engaged :wink: ).”

Don’t get me wrong, it’s not that I do not liks the results of an increase in volume. I’m experimenting.

But of course I want to know “how” and “why”. (I know some “how’s” now but are short of the “why’s”)


Tx

15

Well, i didn´t design the compressor, but oviously the auto makeup gain / ratio and threshold parameters still calculate the, “theoretical” processing of the audio signal even without a sidechain signal present. A ratio of 1:1 also doesn´t raise the output. Which means no (theoretical whatsoever) gain reduction - no auto makeup gain.

16

Well it’s probably Twenty Thousand Leagues Under the Sea.

The auto gain is there to provide gain makeup due to the loss of gain when applying compression.

i.e you apply 3dB of compression you’ll need 3dB of gain makeup to keep the levels about the same!

The stock Cubase compressor has an auto gain makeup function (when switched in) that I can only assume applies gain based on threshold and compression ratio? So when the side chain is engaged I presume the gain makeup circuit is not aware of this fact and applies gain to the output regardless.

That’s the best explanation I can think of!

17

I can stand only so much “deep-diving” with you guys and I think we were almost there.

I understand the preceding two replies and will make that part of my "expert knowledge bank :nerd: ".

:wink: Regards from the Southern tip of Africa!

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You did ask :mrgreen: