Master rack via Loopback or Insert Background rack

Dear all,
inspired by: How freaking stupid I created a master rack in the Background rack and loopback to that in the songs.
That works nicely but recently I have issues with the metronome or media player files in the song (for exercising I have a media player in the song,…). When I stop the media player it can take up to minutes before the system reacts, meantime it is grayed out or not-responding. Same happens with metronome, when I stop it it will continue for some or more time before it really stops. I do have the impression this has to do with the loopback to the background rack.
In previous items I’ve seen the suggestion to send the audio to the master by inserting it into the song: Kontakt 5.1 loading time - Cantabile Community (

So my question is: what is the present best practice for the Master rack?
thanks for your answers!
cheers, Joop

At present, your best option for a master rack (managing general output processing) is still to have it in all your songs. Sending audio to the background rack via loopback introduces another buffer cycle of latency, which you’d typically want to avoid.

There is an item in the Cantabile development backlog to create separate Input and Output background racks, which would then enable input and output processing without added latency (since audio and MIDI will flow in a well-determined direction, so Cantabile can handle everything within one buffer cycle. But when that happens is up to @brad

So for the moment, keep your master rack in your songs - once the new features arrive, it’s easy to change that song-level master rack to send audio directly on to the new output background rack, so you won’t have to change existing songs. Easy migration…



Thanks for the quick response! So, rather having the Master rack in the song, even over having the background rack inserted in the song.

I don’t see the logic in inserting the background rack in the song - wouldn’t that mean that you have your background rack active twice?

The background rack typically serves more purposes than just output processing - my background rack is full of bindings that take care of all the faders, knobs, buttons etc that help me navigate my rig and that aren’t song-specific. Stuff like setting volumes, switching states or songs, starting/stopping playback, etc. That is stuff you wouldn’t want to have replicated in every song, so it is tucked away in the background rack and just “always there”.

A master rack would typically be something you’d want to have in a similar configuration, since it typically doesn’t change between songs, but unfortunately with the additional latency, it makes it problematic to have it in the background rack. That’s why I have it in every single song. My background rack is full of a lot of complicated routing and binding for controlling my configuration and equipment.

Hi Torsten,
it was a suggestion in Kontakt 5.1 loading time - Cantabile Community (, but that was 2017, so that might be outdated.
If I understand well Brad is saying it is instanced once, so no duplications: Master Rack… how freaking stupid am I? - Cantabile - Cantabile Community (
My background rack is not so complicated yet, so for me this could work, however I would rather follow a best practice now and avoid problems later.

Hi Joop,

the consensus at the time was that there wouldn’t really be an advantage of inserting the background rack versus inserting a linked master rack - in both cases, you explicitly route to a rack inside the song. And in both cases, Cantabile makes sure stuff isn’t loaded multiple times.

And it is a lot more logical to have a specific master rack (that is focussed fully on output processing) in your song than insert the full background rack with all its stuff that is in it for other purposes (like I described above).

Keep things simple and logical - background rack is for background stuff; putting it into songs kind of defeats the purpose…

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:+1:I really appreciate your feed back, very helpful