Hi all, I’m 99% i read a post where someone attached a screenshot of a signal follower & Hydra on a Kick trak which was ducking lots of other tracks that had gainers on them?
I have searched but cannot seem to find that post ? Can someone advise how to set up a SF & Hydra on on track to duck other tracks?
This DSP chain should do the trick, only with a custom envelope controlled by a key tracker instead of the signal follower:http://forum.renoise.com/index.php/files/file/98-custom-key-triggered-envelope-generator/
Using signal follower is even easier to set up, you just hook the output of the sf to the inut of a hydra, but you can’t adjust the duck in the same way.
Hydra Meta device is for multiply a meta signal only. Basically you simply put a signal follower on the trigger track (e.g. kick), and an additional gainer on the target track. Then you have to connect the signal follower to the gain of the gainer. You also can use an EQ5 instead a gainer device, if you only want to duck low frequencies, by connecting to a band gain of the EQ5.
I usually put the gainer/e5 on a send track (and then dry/wet-mix the direct track output vs. the send track amount), which is a bad practice when it comes to multitrack audio export (since then you will only get one summed up track). So the best practice (but also more complicated) would be to place the gainer/eq5 on each track individually and doing a multiplying of the signal follower’s meta signal using a hydra device.
This concept is quite ok, but since the signal follower kind of lacks of typical compressor dynamics (and the attack/release parameter is not very precise either for low values), you will of course only get the dynamics character of the signal follower. For getting a clean mix though, this is a fine approach, at least I can recommend this.
Lot of people (including dblue as a dev) are using an lfo (or name it “envelope”) instead. The LFO is set to “one shot” mode, and will be triggered thru the reset field. An signal follower or “midi” key tracker simply will trigger the LFO’s reset. This approach is the same then like using the LFO-tool VST, only that the Renoise’s LFO is not capable of drawing exact curves, but mostly the similar possible curve is ok enough. This scenario should be used, if you want to hear obvious ducking in your song as a stylistic element.
The signal follower also can listen to a limited frequency range only (right top area). Keep here in mind, that listening on bass only could make the triggering too late, so also try to compensate using the “look ahead” parameter. Best practice here to have a clue about the result is to listen to the target track in SOLO mode, and not in MUTE-OTHERS mode (this is switchable in the Renoise config under “Plug/Misc”), since the MUTE-OTHERS mode also disables meta signal flow, but the SOLO mode doesn’t.
Lot of people (including dblue as a dev) are using an lfo (or name it “envelope”) instead. The LFO is set to “one shot” mode, and will be triggered thru the reset field. An signal follower or “midi” key tracker simply will trigger the LFO’s reset. This approach is the same then like using the LFO-tool VST, only that the Renoise’s LFO is not capable of drawing exact curves, but mostly the similar possible curve is ok enough. This scenario should be used, if you want to hear obvious ducking in your song as a stylistic element.
This is the technique i linked to in my last post (Key triggered custom envelope). As an additional touch you may also combine the two techniques by making a signal follower control the amplitude of the custom LFO or the hydra min/max setting or whatever. Only the imagination can stop you from getting the dynamics you want. 
Hi thanks for the tips guys, the one shot LFO is working great but I’m getting clicks on the Bass synth when it’s ducking ? any workaround for this ?
Hi thanks for the tips guys, the one shot LFO is working great but I’m getting clicks on the Bass synth when it’s ducking ? any workaround for this ?
Did you just use the envelope that is there by default? The whole point is to change this LFO envelope into how you need it to be. Move the points to where you don’t hear the click anymore.
Try to grasp the logic of meta routing - source is signal follower, key/veltracker->lfo, etc. The hydra is just for spreading a source to multiple outputs, like if you wish to duck multiple chans from the same source. Hydra will also allow using different parameter range warpings as you can define for each destination what to wrap - you can duck one chan heavier than another etc. After source and possible spread is destination, which might be a gainer for radical effects, an eq for more surgical, or even a filter which will give swishes etc. you can automate almost everything, also compressors thresholds or gate parameters which are the best to duck with if it comes to native devices imho.
When it comes to the bad clicking in bass freqs I feel your pain. Some results can be bad, like automating the eq in too aggressive ways. Try automating devices with smoothing, like compressor or gate which have attack settings. Keep in mind if you duck low frequencies, if the envelope of ducking is faster than the frequency there might be a new audible transient generated by your action. Compressor attack or the like might smoothen stuff. Also the gainer seems to be smoothed a bit. And lastly some clicks generated by poor dsp might also not be noticable in the final mix, but this is…errr…uargh…
The signal follower is also a bit flaky, it might overshoot sometimes and is hard to tune. I really prefer key/veltracker and lfo envelopes for controlling stuff, it always be straight and easy to tune…sig follower is last resort when I can’t sync to midi/note data but only have frequencies in sample data. Or use pure dc samples. The signal follower really sucks for bass freqs.
Last but not least - experiment, try to find what suits you best. For clearing bass, for ducking ambience to get more power, for seperating action of critical band maskings - I bet everyone has the own secret recipes…
I’ve just started using the signal follower, for ducking check out the tutorial xrns named**Tutorial -Ducking (Sidechaining)**it helped me get started and figure out the basics.
read through this a bit and am not sure if it’s relevant to what i’m seeing/hoping for or not.
I’m hoping to send one velocity tracker to a hydra and then the output of the hydra to multiple different LFO resets.
i’m not dead in the water because i can just make multiple velocity trackers and use them 1:1 on the the different LFOs, but i was hoping to do tracker->hydra->lfo1, lfo2, etc… to keep things a little cleaner.
so… that doesn’t work.
in a way it seems like the hydra only sends an output to downstream DSPs when there is a change in the value of the hydra input.
if i send key tracker output to the hydra, and then hydra to lfo reset, it will reset the LFO loop position according to the notes i play, as you’d expect, however it only does that if a note is different than the previous one.
in other words, if i do key tracker -> lfo reset, and hit the same note over and over, i see it reset the LFO loop each time.
if i put a hydra in the middle, i only see the lfo reset when i play a note that is different than the last one.
this would seem to imply that velocity tracker would work in the same way, sending the reset downstream only if the velocity of a note changed.
is this known / expected / working as designed / not a bug / EWONTFIX kind of thing?
This is known behaviour of the meta devices.
The key/vel trackers seem to send “events” suitable for retriggering lfos on the same position.
The hydra will not pass on those “events” 1:1 but ignore them when they have exactly the same value.
The formula device will actually do the opposite, and send the event on every tick even if the value hasn’t changed. But this is also unsuitable to control lfo resets, as the lfo will just freeze its position being confronted with the same “event” on each tick.
Not sure right now about doofer/macro, meta mixer, …
In one ocasion I solved the problem in a rather complex manner, using both a key and a vel tracker of the same instrument, the vel tracker triggering a dummy lfo that would just out 1 when triggered, and then 0 on all succesive ticks. Both trackers fed into a formula device that would out the key tracked input when the vel tracker tick goes one, and then add a tiny value to the output when the vel tracked goes to zero again. This will trick the hydra controlling the lfo resets to always output the reset “events” because the values are a little different, but though when the offset is very small the problem is still a one tick delay/freeze in this setup. And it is a very cumbersome thing to set up with the meta devices all over the place.
On the other day though I was sober again, and it occured to me that I could just use multiple key/vel trackers setup the same way instead of the hydra. Haha!
No, I think I did it because the setup needed a formula device in between the chain, but I cannot remember details or in which project file I had done this. Try to think if you really would need such solution, I’d be happy to recreate an example for you as an exercise. But I’d rather try to simply duplicate the key/vel trackers for each LFO you want to control first.
read through this a bit and am not sure if it’s relevant to what i’m seeing/hoping for or not.
I’m hoping to send one velocity tracker to a hydra and then the output of the hydra to multiple different LFO resets.
i’m not dead in the water because i can just make multiple velocity trackers and use them 1:1 on the the different LFOs, but i was hoping to do tracker->hydra->lfo1, lfo2, etc… to keep things a little cleaner.
so… that doesn’t work.
Why doesn’t this work? I don’t understand as there is no problem doing what you explain here., you may very well control resets of different LFO’s through a hydra with any tracker device.
in a way it seems like the hydra only sends an output to downstream DSPs when there is a change in the value of the hydra input.
No, the hydra can send to any DSP, but the signal follower can’t send to DSPs that is processed earlier in the chain or tracks to the left. You may however use a hydra in between and then it suddenly works for some reason, don’t ask me why. 
if i send key tracker output to the hydra, and then hydra to lfo reset, it will reset the LFO loop position according to the notes i play, as you’d expect, however it only does that if a note is different than the previous one.
No, the key tracker resets at any input, if the note is the same as the previous one it should still reset to that same position as the last note input. I suggest you take a look at this:http://forum.renoise.com/index.php/files/file/98-custom-key-triggered-envelope-generator/
It’s set to reset every note to point 0, every note input will reset the LFO to it’s start point and is set to play the envelope once and then stop at point 64. It works excellent for ducking and also the opposite
in other words, if i do key tracker → lfo reset, and hit the same note over and over, i see it reset the LFO loop each time.
if i put a hydra in the middle, i only see the lfo reset when i play a note that is different than the last one.
You do it the wrong way around, you need to make it Key tracker → LFO Reset → Hydra → LFO/LFO/LFO/LFO
this would seem to imply that velocity tracker would work in the same way, sending the reset downstream only if the velocity of a note changed.
Only the signal follower has this limitation, it actually makes sense because how can you follow a signal that is constantly changed by that same signal follower?
is this known / expected / working as designed / not a bug / EWONTFIX kind of thing?
This is actually a non existing problem as far as i can see, i don’t really know how you came to all your conclusions. 
If you tell me what exactly you want it to do i can probably make a chain for you.
Key tracker → LFO Reset → Hydra → LFO/LFO/LFO/LFO
That solution to the problem is pretty cool. The first LFO would just take the role of retriggering and controlling phase of the other parallel ones. Thanks for sharing this idea.
hi; thanks for the reply before 
i guess my root assumption/misunderstanding is that “hydra” will ingest any kind of output from any DSP.
here’s another example where i keep wanting to send the output of Key Tracker to a Hydra. basically i want to have an arbitrary number of DSPs get the “Note” i just pressed, without having to do key trackers for each one.
key tracker -> hydra input
hydra out1 -> lfo / reset (min 0 max 0, so it always resets to the front of the oscillation)
hydra out2 -> ringmod / note
the ‘key tracker -> lfo reset -> hydra -> lfo lfo lfo’ gives me multiple LFOs oscillating at whatever the “primary” lfo tells the hydra to oscillate at, which isn’t what i’m trying to do.
i’m trying to do something like this:
key tracker -> lfo reset
key tracker -> ringmod note
key tracker -> another different lfo (such as different frequency/rate) also reset each time i hit a note, even if it’s the same note.
etcetc. like i’m trying to use the LFOs as envelopes, and reset/retrigger them on note-ons.
without having to instantiate key trackers for each one of them.