Last time I tried, it wasn’t possible to freely trigger multiple phrases in Redux simultaneously. Phrases are selected with CC, so if you want to play a chord with separate phrases from the sequencer you can’t (AFAIK).
If possible, I suggest making this possible by using MPE. Maybe that seems a bit hacky, but it seems better than not being able.
Go to the keymap tab in redux and drag different phrases to the horizontal keyboard. Here you can set the range / how many keyboard notes per phrase and enables you to play different phrases at the same time. Make sure the mono icon isn’t toggled on.
I don’t think that’s it. This would be locked to specific keys. You’re not able to play any chord, as you would trigger voices in Renoise with Z01, Z02, Z03… Or am I missing something?
Keymap mode is kinda usable for drum sequences and simple arps… not chords.
I’m confused with what you’re trying to achieve exactly?
Perhaps you mean this, toggling on the sample icon in the phrase editor will add an instrument number, allowing to play the phrase as a chord, turn on this icon;
Playing phrase 01 as C-3, phrase 02 as E-3 and phrase 03 as G-3 at the same time via MIDI. (Similar as you would do in Renoise using the Z01, Z02, Z03 on the same line)