So I’ve been doing tons of research on the OP-1 as I’m saving up to get one very soon.
1 - you can play all 4 tracks, be playing some other sequence non recorded, and monitor line in at the same time
2 - the whole album mode thing allows you to basically do anything in real time and records to a wave file
3 - sequencer that either works in synth or drum mode. Basically you can play 2 patterns at the same time, or chain patterns like ableton. Each pattern is its own key on the keyboard
4 - its mysterious to me, I get noise if I don’t use USB and use headphones, if i use monitors and plug my usb in i don’t.
2: There are some limitations when it comes to playing live like you can’t copy and paste (lift & drop in OP-lingo) segments without it having a noticeable effect on the playback, e.g. a brief silence. Also you always drop where the play head is, so you can’t pre-arrange on another part of a track while a loop is going on.
3: Here’s a relevant video from the TE