Signal Follower For Sidechain Compression


I’m pretty sure this was discussed before, but I couldn’t find anything adhoc so I decided to bring it up again.

Though I like the Signal Follower, I have the following slightly provocative theories, please correct me if I’m wrong

1. Signal Follower controls Gainer

You can build a primitive sidechain compressor with Signal Follower and Gainer

Track A: Signal Follower with appropriate attack and release setting
Track B: Gainer which is controlled by Signal Follower

Result: the signal in Track B is controlled by a simple (?) compressor.
But this works and is better than nothing !

2. Signal Follower controls threshold of a compressor

Track A: Signal Follower with appropriate attack and release settings
Track B: native or 3rd Party compressor whose threshold parameter is controlled by Signal Follower

Problem: compressors are usually NOT MADE FOR THAT ! Their algorithms are usually optimized to work for audio signals which pass a FIXED threshold, not for dynamic threshold changes. IMO as a result you’ll get a different compression result for the non-sidechain signal of Track B. Nonetheless this is experimental and nice, but good for real life ? I’m not sure. I think it makes sidechain compression even more complex to understand because of the unusual indirect impacts on the compression behaviour AND you have to control more parameters (e.g. 2 x attack and release)

3. I have no other idea how I could use the Signal Follower for Sidechain Compression

Pre- or Post-Gain automation is the same as 1. Maybe ratio automation ?

No decent 3rd Party sidechain compression is possible with Signal Follower.
3rd Party sidechain compressors are not really usable. It’s a fake. It’s not implemented, yet !

To use them effectively a real routing matrix like in Reaper or something else is necessary. [/b]

Haven’t played that much with Signal Follower so it may just be me ;)
But I replaced the Sidekick VST in a song I’m working on and I couldn’t get the same result as with sidekick, at least not while I was experimenting. I tried basicly the same things that you did.
If you can get the same or better results with SF then it would be great if someone could explain the procedure.
Again, I’ve only played with SF for a short while.

Hmmm, can someone explain what happens INSIDE a sidechain compressor, how it processes the sound? To my limited knowledge, all that makes a sidechaining compressor different from other compressors, is the INPUT which allows the THRESHOLD to be ‘triggered’ by the audio send through it…?

The difference is that the compressors detector signal is the sidechain signal and the compressed signal is the actual signal of the track. E.g. the sidechain signal is the kick and the main signal the bass line. Whenever the kick plays and passes the threshold the compressor works and compresses/ducks the bass signal. Pretty important for all kind of electronic music IMO. In a normal compressor the detector signal and the ducked signal was the bass line.

In a real hardware compressor with a sidechain insert, such as this one which I used extensively before I became a vst whore, all that happens is that the amplitude modulation is applied to a different signal to the one being analysed. (edit: as you’ve just stated yourself).

Assuming that the signal follower in Renoise is running the exact same code as the native compressor, which is admittedly simple and straightforward but by no means ‘primitive’, then linking it to a gainer is indeed ‘real’ sidechaining and not a ‘fake’ at all.

I’ve been using the signal follower with a gainer quite a lot since the beta came out and it behaves exactly as I’d expect. So to say “No decent sidechain compression is possible with Signal Follower” is complete and utter bollocks.

Do you think an SF controlling a gain before a compressor would be the best way if you want sidechained input and compression?

That’s the point:

  1. You assume the Signal Follower in combination with the gainer works like the native compressor (attack, release and so on). Even if it looks a lot like e.g. Reapers Compression detector, I don’t know and assume it doesn’t, since it’s main goal is parameter modulation and not signal compression. What about ratios ? Moreover: what about Knee’s ? What about Auto-Makeup ? What about bus compression ? Ok there is dest min/max and the scaling. Can I really use it for that ? Looks complicated to adjust.

  2. Even if it works similar to the native compressor, I’d say it’s far from decent. There’s a reason for expensive 3rd Party compressors with it’s own characteristics. It’s nice that your solution works and is decent enough for you, but I want to use 3rd Party sidechain-capable compressors inside Renoise, too. Not only the native stuff. I think I’m not the only one and one can’t do it using the signal follower. Is that complete and utter bollocks, too ?

  1. I do assume, because I assume that the developers know what they’re doing and wouldn’t waste time writing repeat code. It sounds like it does anyway :)
    Here’s a quick test: (edit: renoise 2.5 b4)
    The signal follower’s control output sounds like it’s being ‘quantised’ a bit which is understandable, some plugins would probably freak out having their parameters changed as rapidly as once per sample (which is what would happen inside the native compressor).

Ratio = min/max
Knee = scaling
Auto-Makeup isn’t there but I can’t say I’ve ever used this in VST compressors that do have it. You’d only want this for broadcast/radio situations I should think.

  1. So you’re basically saying Renoise doesn’t support multi-input VSTfxes yet. Yeah this is true, and I agree it is badly needed, but its a separate issue entirely - I’m just here to defend the signal follower because I loves it!

This is what Taktik likes to hear I guess ;-). Indeed they’re often lazy, too and tend to re-use code, but in
this case I’m not sure. It’s still parameter automation, not DSP processing !

I was thinking about that, too. Threshold was probably sensitivity, but all those things are sensible at first look, but the same as above: still not sure if it’s really so

I’d say also perfect for any DJ with a live set up and Mic !? But I agree it’s not the most important thing.

I really love it, too, nothing against it. It’s a wonderful innovation,
but I’m still trying to find out what it can and can’t.

Multichannel + routing matrix was indeed great

I can defenitely get a good sounding sidechain going on with Renoises signal follower device, but maybe I’m not sure how ‘sidechain compression’ should sound exactly. Can you post an audio-clip on what type of sound you’re looking for Airmann ?

3rd party sidechain compressors can be used in Renoise, I think. Like sidekick, tc works sidechainer & DB audioware sidechain compressor. Those are the plugs that are supposed to work in this realm, no?

Those plugins like sidekick work by sending audio between each plugin instance using virtual channels.
It’s not true multi input routing because renoise doesn’t support that.

So it isn’t sidechaining if it isn’t multi-input routing done natively in the sequencer? Those plugins do send 0 and 1’s right? :)

I think there is not something like “the sidechain compression sound”,
rather the sound of the ducked main signal depends on which compressor I use for ducking.

I want to use sidechain-able compressors e.g. like

I want their feautures and their sound.

I’ll try to create a demo and post it.

As a concept a compressor is a tool to control the overal volume of a musical phrase. Nothing more nothing less.

If you agree with that, than controlling the volume of a bassline track by a SF on a kickdrum track, gives you exact the effect of a ducked compressor.

The only difference is that compressors add characterics to your sound because they use tubes or other electronics to make it sound different, these are extras. VST compressors are programmed to emulate hardware compressors, so they add a little personality to your sound too. This has nothing to do with the original concept of a compressor; controlling your volume.

In my humble opinion, controlling the volume of a track by a signal follower gives you the same effect as a ultimate-transparent compressor with sidechain input.

a fx plugin vst with sidechain have 4 instead of 2 inputs.

in other hosts you can plug/route a signal into the other 2 “sidechain” inputs
of a plugin, e.g a sidechain compressor.

this doesn’t exist yet in renoise. the signal follower only sends a
signal to another channel, but doesn’t send/route it into the extra inputs
of such plugins.

i hope the renoise fellows will get this done, soon!


not everything is about DUCKING a sound with a compressor, guys.
there’s also alot of other stuff to do with sidechain inputs!!!

not that this does necessarily mean something, anyway each of those softwares cost at least as much as Renoise itself :)

If I had to choose between advanced signal routing and the signal follower, i’d choose the signal follower, it’s does more for me than I hoped for.

Thanks devs!

you can use rewire to slave renoise to a host (e.g reaper or whatever) that will allow you to use 3rd party sidechain compressors…

i like the fact that renoise treads its own path in software development!

it gives it a unique sound…

this is a good point i feel- you can supplement the sound you get from the signal followed part by using other “character” plug-ins

Its true that a signalfollower attached to a gain is not “exactly” the same as a sidechained compressor. But it results into the same “effect”, so do we really care, or is this nitpicking?

Even if you can’t do real sidechaining with compressor plugin XYZ now, you can do stuff you can not do with !any! plugin. Modulate a filter or distortion or chorus feedback or delay length or whatever with an input from another signal. Thats quite cool isn’t it? And this goes far beyond the traditional sidechaining effects, which are IMHO a bit overrated.

We also never said we don’t want multi channel FX routing anymore, with the signal follower implemented. Thats simply a different topic. We also never claimed its a “replacement” for your favorite sidechain compressor VST.

Summa summarum: You should see the signal follower as a new tool in your sound manipulating arsenal in Renoise. If its real compressor sidechaining or not? Honestly, I don’t care, as long as it sounds good and allows me to do stuff I could not do before ;)

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Different compressors can sound wildly different from each other.
For ducking a bassline from a kick, the signal follower worked for me - i dont think it really matters that its not ‘texk book’ side chaining.
The noise that comes out the speakers is the important bit.