Hi Gavin, the basic concept is that the sounds from the sound pool can be locked to steps, just like any parameter can be locked to a step, by holding down the trig key and choosing a sound which you’ve added to your sound pool.
It doesn’t make the tracks polyphonic, but it does allow you to put more than one type of sound (sample saved with settings) on a single track, so if you wanted kick and snare on one track you can lock the sounds to the appropriate steps, and it takes up less track-space. Since you can’t do this with raw samples (the track sample) this offers some added flexibility.
The downside is that if you want to mute one and not the other, you can’t do that without setting up fills or a different pattern due to the shared track. Also due to the monophonic nature of the sample player, one sound will still choke out another so you’ll lose the tail of a long sound (with the exception of the onboard effects) but the audio tail will be choked out by the next sound on that track.
I bookmarked a post with a nice write up on this and there’s no way I could explain it better than this so thank the person who wrote it or something. Once you execute the act of adding sounds to the sound pool a couple of times, it becomes a pretty simple act to perform and so long as we’re talking about Digitakt 1, then I assume this will work nicely for you.
Let me know if that doesn’t click for you, but if you’ve been using the digitakt for a while then it should probably just be a matter of following the instructions laid out in here.
To be clear, you must save a sample as a “sound” in order to use sound locks. You can load any sample and save it as as sound, even dry. Or you can tweak a sample and then add the “wet” sample (with effects, pitch, LFO, tweak the envelope etc.) and then save that as a sound, whatever it is, it must be a “sound” and not a “sample” to use in the sound pool and lock to a step, just understand that the machine sees these words as 2 unique things.