First note played causes a crackle sound. Caused by Replika?

Tyrus

I have a bunch (~50) instances of the Kontakt instrument I'm writing loaded up in a Cubase project. Each instance of my instrument is in its own Kontakt instance; each Kontakt instance has only 1 instrument loaded. When I click on each track and play a note on my keyboard, most of them elicit a crackle sound followed by the normal instrument sound. If I continue to play notes, there is no crackle sound and the instrument sounds normally with no crackle sound. This is only an issue with the first note played in an instrument after it has loaded.

I think I've confirmed that Replika delays are somehow the cause of it. I don't hear the crackle sound if I bypass the Replika delays before playing notes. And if I bypass the Replika delays, play some notes, then unbypass the Replika delays, the first note I play has the crackle sound.

The crackle sound seems to be linked to the first note causing a spike to 100% of the real-time audio processing load indicated by Cubase.

It seems like Replika is doing some extra processing the first time it receives audio data. Is there anything I can do about this?

Other possibly useful info:

• Two Replika delays are send effects.
• One Replika delay is an insert on an instrument bus.
• At the end of the insert effect chain on the instrument bus is the Send Levels insert.
• Bypassing some Replikas and not others sometimes removes the crackle and sometimes doesn't.

Kontakt version: 6.6.0

Cubase version: 8.0.40 64-bit

OS: Windows 10 Pro version 21H1

Audio interface: Focusrite Scarlett 8i6

CPU: AMD FX-8320, 4-core, 8-thread, 3.5GHz

RAM: 32GB

Kubrak

You speak about 50 instances of Kontakt. Is 32GB RAM suffitient to keep it all in memory and not swapped to disc?

And also might be the case that before you start playing CPU has lower clock. It increases clock fast when one starts, but it may take too long not to make dropout in sound. Check CPU power management settings.

You may increase audio interface buffer size a bit, if acceptable.

Tyrus

Thanks for the response. :)

I checked my Cubase project, and it was only using ~22GB of RAM. Though just to be sure, I created another project with just one instance of Kontakt with my instrument, and I had the same crackle sound problem.

CPU power management settings weren't something I was comfortable changing, so I didn't do anything there.

I tried increasing my audio buffer size from 192 samples to 1024 samples. This actually did eliminate the crackle sound, though Cubase does still indicate a 100% spike in real time audio processing load. If I have a problem like this in the future, particularly for instruments that are not my own, I will remember to do this.

One more solution I found today was to add a play_note() function in my on persistence_changed callback. Specifically I had it play the lowest note of my instrument at the lowest velocity for the shortest amount of time: play_note(35, 1, 0, 1). It's hardly an elegant solution, but I think I'm gonna go with it. I'll have to add a little extra code to make sure that the note gets played through all the delays, so that they are all "initialized" and don't crackle when they're played.

EvilDragon

Does this also happen in other DAWs?

Just for reference, a single instance of Replika effect takes around 70 MB of RAM. So that's 210 MB for your 3 Replikas in a single patch, and then if you have 50 Kontakt instances with that same patch, that's 10.5 GB of RAM.