Audio stops when using gain plugins as aux control [solved]


I am a new Zynthian user, and recently bought the v4.2 kit with RBPI 4 (8gb ram) because I’m just a musician with only very superficial technical skills in building/programming stuff, and the kit was pretty straightforward to build. I am interested in using the Zynthian in a live setting, and therefor I’m curious how reliable it is, or which way of using it is the most reliable, and which way is more risky. For this reason I have been testing out my Zynthian for some days, importing my own soundfonts etc. All was working very well and I’ve been very pleased with the results, also how intuitive the GUI is. Today I finally found a problem and I’d like to know if I’m doing something I shouldn’t be doing.

I added an Audio FX layer with 8 gain plugins in parallel, and after this I added a Tal Reverb II in serial. I routed some instrument layers (fluid synth) to these gains (each layer its own gain) and the instruments were also simultaniously routed to MOD UI for a master FX chain. The audio FX layer was also routed to MOD UI. All was working well and I was able to simulate aux sends this way, until the audio suddenly stopped working when I moved one of the gain controls in a gain plugin. The only way to get the audio back was to reboot the Zynthian.

Is there a better way to simulate this type of analog mixer audio routing? Is it normal that the audio stops working like that, when using multiple of the same plugin in one layer?

I realize I am a total beginner so I apologize if I have missed something obvious!



Oh man, you may have just saved me from having to purchase a larger mixer.

I can’t believe I didn’t think of routing things in this way, so after seeing your post I had to give it a go.

I had an instrument on Channel #1, then added a gain layer to Channel #6 (just my convention). I added a TalDub effect to the gain layer, turned the dry level all the way down, then routed the instrument on Channel #1 to output via the gain layer on Channel #6, then mapped the volume control on the instrument and gain layer to my faders.

For some reason after assigning the instrument output to the gain layer the Zynthian auto-routed it to the TalDub effect too, but after undoing that (so the instrument was going to the system outs + gain layer only) I was able to do some dubbing!

So this is definitely possible on the Zynthian! I would start with some simple routing to prove everything is working, and have a play to make sure it works. Maybe prove your MOD UI instrument on its own too, just to verify routing is correct there. Then hook it all together and hopefully it should all work out.

I do find that the Zynthian does some strange things with routing, especially if it’s been on for a while and I’ve been playing around adding / replacing instruments and effects. If I’ve been experimenting a lot, I’ll save the state and do a restart, recheck the routing and only then get down to serious business.

One tip is to install patchage as this provides visual confirmation of the internal routing, and the ability to manipulate it. There are some routings that aren’t possible via the Zynthian UI (at least as far as I have been able) for instance routing audio to secondary outputs of effects for ducking/compression etc so patchage is a useful tool to get to know anyhow.

FWIW, I also have the official kit and the following versions:

zyncoder: stable (d852c8f)
zynthian-ui: stable (01c808c)
zynthian-sys: stable (df05b71)
zynthian-data: stable (194fd59)
zynthian-webconf: stable (dec5f31)

Thank you again for your post! I’ve been looking into a better mixer with more channels and aux sends, which would have meant more cables and another sound card and a whole heap of expensive mess. I may still end up going this route at some stage, but thanks to your post I can get started making music the way that I want to right away!

Edit: After re-reading your post, I realise my experiment was a little simplistic and not quite what you asked. If I get time tonight I’ll set up a reverb and echo, using faders mapped to a gain layer at the end of the chain to control their volumes, routing the instruments to parallel gain layers at the beginning of the chain, mapping them to encoders ala traditional aux sends on a mixer. Will report back.

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Bah, couldn’t help myself…

It was a simple test, but it did prove that it works. I added a gain layer in parallel for each instrument, then TAL Dub, then another gain layer for volume and manages to get it working fine.

Thanks again for this inspiration! Only problem is I once again need to rethink how I map my MIDI controller again hahah

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Ahh great to hear that it worked for you! My problems also totally dissapeared now, after replacing the gain plugins with 2ch mixer plugins! Seems to work really well even with those 8 plugins serving as buses for the two FX layers, one for reverb and one for delay, so 16 plugins in total! I can’t wait to map a midi controlled to this setup and try some hands on mixing this way. I’ve ordered the Faderfox EC4 to keeps things super portable, seems like a perfect match…

The only thing I couldnt figure out yet is how to route the physical audio inputs on the Zynthian to a specific send, but I still have to check out patchage, which must be super helpful for more complicated routing setups like this! Thanks for the tip!

Oh well done :smiley: !!

Could you.

1/ Add [Solved] to the title of the thread
2/ Provide a :face_with_monocle:


Sure! I tried to edit the title but it seems I am not able. Is it because I have already edited my original post once? The picture I added ended up in the middle of my text which is why I edited it initially. Obviously a beginner here!

Also I am finding more problems regarding my situation, but they are different problems. Should I open a new threat or continue here? The AMS 2ch mixer plugins i am using as sends, are added in parallel, but some of them randomly turn to serial after rebooting the zynthian. it could be due to the quantity of plugins, as I added 16 of them now… Still have to try patchage also, which might solve this?

A short demo will soon follow once I have it all working properly!

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I took a leaf from your book and am using a mixer now too. A few things to keep in mind:

  • When you mentioned using a mixer instead of a gain I thought that was genius, because stereo! But AMS 2 channel is stereo to mono, so I’m using AMS Stereo 2CH Mixer to get stereo->stereo

  • I had to map my controller to 0-64 rather than 0-127 as the volume/gain dials on most of the effects I tried went -X to 0 to +X and I nearly blew my ears off :laughing:

  • Definitely check the routing in patchage. When adding gains and mixers as parallel, it auto-routes captures to the inputs, even if the ‘host’ effect has captures turned off. This is especially bad if you’ve accidentally amped up the gain through several mixer layers like I had.

Annoyingly, whilst disconnecting the capture routing in patchage works just fine, the routing state doesn’t appear to be completely saved with with snapshots, so isn’t restored on reboot, and every parallel mixer layer is once again capturing input and needs disconnecting.

Another tip there is that you can right click on the captures and click disconnect to remove all connections at once, then re-route the few you might need, so it’s not a huge deal. I hate having to use my computer when I’m playing with music tho.

I’ll post a bug report on GitHub later about these two issues (restoring routing state with snapshots + allow configuration of parallel layer routing / getting parallel layers to inherit routing from ‘host’ / parent) but for now I’m going to get back to dubbing the way Jah intended!

Tis my first proper day off in fecking ages! woohoo! Thanks for helping make it even better, if you hadn’t of posted I’d still be pining after a new mixer!

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Just another update.

I’ve set up my Zynth to what will be my new default state, with four instruments, two input layers, and two effects simulated as aux sends. That means that each ‘mixer’ channel has 8 AMS Stereo 2 Channel Mixer plugins (one for each instrument, two for audio inputs, one for the alternative effect, one for overall effect volume) plus an effect layer. Along with the MIDI effect layer for clocks etc that’s 9 MIDI channels with a minimum of 24 instruments and effect layers (if I’ve done my math right). Hopefully the Zynthian can perform under this load once I get going!

I have managed to retain the state after a reboot. I saved state as default / last state / and a new snapshot. I haven’t tried switching between snapshots tho, and have noticed the capture ports being re-routed at random times, but haven’t figured out exactly when that is. I’ll report that bug when I can figure out when exactly it is happening.

We definitely need a way to address advanced routing of effects tho, so will still add that bug report later.

I’m stoked to have managed to massage the Zynth into working in this way, thanks again for the inspiration! Now I’ve just got to make something musical with all this :laughing:

Hope you’ve managed to get everything working!

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The method of using amp (or mixer) plugins to form a mixer has been discussed in other threads (and at club) in the past. You may benefit searching that out. Zynthian snapshots are based around the configuration done within Zynthian and may not handle manual routing performed. e.g. with Patchage. Patchage is a useful tool to see what is routed where and perform manual tweaks for testing but it isn’t recommended to create production routing as it is a PITA to set up manually before each rehearsal / gig or after any impromtu restarts of Zynthian. There is room for improvement in the Zynthian routing which should be addressed with feature requests. :slight_smile:


Ahh I didn’t realize this had been discussed before, thanks for pointing that out! Just read up on the threads where the mixer option is discussed, sounds very nice indeed! If any ideas come to mind I will suggest them there. Right now all I can do is wait patiently as my skills at helping to develop this are very minimal. Hope this will make it into the stable OS soon!

The biggest help at the moment is just using it at telling people how the experience was and did it produce anything :face_with_monocle: able.
it’s gained a lot of functionality recently and heavy usage is how we’re going to nail down the components we have now.
Repeatability of audio routing is something we are keen to enshrine into the overall system and the implications for such components tends to raise interesting questions. I seem to remember it came down to horizontal or vertical sliders, and then we moved on.
How a multi layer zynth presents audio to its output sockets is important to restore repeatable. And there is the need for output channel handling but whether or not that is one simple overall volume control (possibly with pan) to a fully engineered sub bussing system with Bell, whistles, test tones and soothing back ground music whilst it reboots, is probably a club debate!

Not sure what’s happened, but today my Zynthian did not correctly restore to the previous state, and checking in patchage showed orphan mixers and effects. Re-loading previous snapshots gave similar results.

I did an update (which would clear any hacks I’d added to remove them as possible culprits) but still no dice. Not sure if I can can simplify this routing much more. Will start again with a fresh card and see if I can get something stable.

Definitely would prefer to not have to use patchage, but until we can access alternate inputs/outputs of stacked effects from within the Zynthian interface I’m not sure there’s another way?

Will be fun to discuss at the next Zynth club! I’m not sure my limited knowledge will be all that useful, but I’ve a fairly clear idea of what I want to achieve.

Anyway, hopefully I can get things going again this evening, and get wyleu his :face_with_monocle:


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It warms the bitter burnt out husk of my black and broken heart !! :smiley:

So today I’ve been trying to really get to the bottom of this issue of the seemingly randomly changing of routing settings after rebooting Zynthian. Not sure if this will help in fixing the issue, but at least it might help to predict the behaviour and think of an easy workaraound.

I basically rebooted the zynthian after each change I made while constructing a routing patch with to see when the change occurs. Every time before rebooting I made a snapshot so I could continue where I left off. After a while of doing this I ended up with a perfectly working patch with 14 aux sends (though I believe this number does not matter), 7 for delay, and 7 for reverb, using the AMS mixer 2 channel plugin. Everything worked well until I saved the patch as a default snapshot. Then rebooting the zynthian, and automaticly booting up this snapshot caused the routing to have changed, and strangely this kept changing every time I rebooted after that. Reverting to an older snapshot to recover the previous correct routing does not work. I’ve found that the only way to reset the routing is to build another patch from scratch, with the same amount of sends on one layer, so in this case 7 sends. Adding them in parallel reset the settings back to normal for me. I’ve saved this basic unfinished version with only the 7 sends as a default patch, and opened one of the snapshots of earlier patches that had changed. They were now back to normal! I hope this makes sense somehow, and that the situation does not change again, so this can serve as a kind of workaround, and still have the analog mixer style routing. Just have to remember to never save a finished patch with this kind of routing as the default patch!

I also just received the Faderfox EC4 so hopefully I can set it up soon and record a little demo!

Ah and I forgot to add, that I am still not using Patchage, and not sure if I have the need for it! Setting it up this way is pretty fast (especially since I removed the MOD UI FX chain on my master). And as the “sends” serve more as “receives”, being added to only the FX layer, routing is pretty easy. Maybe the term send was confusing in the sense that it sounds like I’m adding them to the instrument layer I want to send to an FX layer, but it’s actually the other way around, where the FX layer has many receives, which can be routed to from the instrument layers.

patchage is more of a test and analysis tool from the perspective of zynthian rather than something to use to configure. IT wouldnt be my favourite app to run on stage for example. Generally we try to define the way we would like the zynth to work and use patchage to confirm the method is sensible and viable and then implement the results into the zynthian GUI.

Patchage may give some evidence during a fault state. If you run patchage and check the connections then trigger the fault and check patchage again we would know if this is a routing issue or something else.

Hi @Jacco!

Congrats for your work!! You are pushing zynthian to the edge and it seems there is some problem when restoring snapshots with complex routing. Please, could you share your snapshot? I will try to find where the problem is :wink:


Thanks! I think I pushed it too much for a moment when I added 16 aux buses (32 AMS 2 ch mixer plugins!). The Zynthian froze every time I tried to remove any plugin or layer, and also when trying to switch to a less complex snapshot. And as it was my default patch, I had to delete it via the browser to be able to use the Zynthian again. This is the snapshot I had working earlier, with 14 auxiliries: 014-JV;Gain.zss (52.8 KB)

I experienced this too yesterday. Things initially appeared to be working well, but then attempting to remove a layer (and not one of the big mixer panels) caused the whole machine to crash. After a couple of hard reboots I was able remove a couple of layers, but more crashes and glitches had me abandoning the idea of aux sends for now :frowning:

With regards to Patchage, aside from just debugging existing routing there’s another reason I need to use it: as far as I can tell it is impossible to decouple the Zynthian’s physical inputs from a mixer layer added as parallel without using it, and I’ve been playing with a drum machine for some extra percussion with the hope of being able to send it through the ‘aux sends’ as I would an internal instrument.