"Still not quite understanding how to use the monitor output alone, and not have the audience hear it." - André
Oh, sorry, I should have been more explicit about describing this use case. To use pitch preview (PP) with the monitor output alone you would split the stereo MONITOR output between left and right via the PREVIEW:mode knob. For its settings please refer to the table on page 20 of the manual or the last page of the quick reference guide:
https://d-lev.com/support/D-Lev_Quick_Reference_2024-01-08.pdf
Modes 1, 5, and 9 split L & R, where L is for the audience and R is for player PP monitoring. In these modes L will contain NO PP, and R will contain ONLY PP, so if the player wants to monitor both their playing and PP, they will need to somehow mix L & R externally (electrically or acoustically). Mode 1 applies whatever pitch correction is being applied to the voice also to the PP pitch. Mode 5 gives no pitch correction to the PP pitch. Mode 9 applies hard quantization to the PP pitch.
In my mind, the "right" way to handle PP is to install a second LINE DAC (via SPDIF on J10) and use this exclusively for the audience, which then allows modes 2, 6, and 10 to mix the synth and PP on the D-Lev rather than externally. It also allows for player stereo monitoring, which I feel is superior, particularly when reverb is being used.
There are some voices that use the PP oscillator as a 4th oscillator (modes 0, 4, and 8) or as DC stimulus (mode 12) for percussive ringing of bells and such. This obviously rides roughshod over the whole concept of PP.
"But may be I wont need the monitor and will only use the tuner. I can only answer that when trying and playing the instrument."
PP is there in analog instruments because players need something to help them come in on pitch, and it is a fairly trivial thing to implement. I personally find the constant wheedling of PP in my ear very distracting, though you can set it so that it does "ducking" (only plays during voice silence).
I only know of two players who use the pitch preview feature: Roger Hess and Rob Schwimmer. I don't believe Roger uses it full time, and Rob only uses it in rare situations where he is improvising on the fly in louder band type settings. I believe most find the tuner adequate for the task, and I of course watch it like a hawk 100% of the time during play.
But, yes, give it a go as-is and see what you think, and give yourself room to experiment. It seems that many crucial aspects of musical instruments can't be known purely by thinking about them before the fact.