I just unboxed an L-20 and mucked about with it. I've used both flying fader and "passive fader" mixers before and this mixer is much more like an early Presonus Studiolive (obviously).
I MacGyvered a WAV file of a Ringo Starr tune into a project - it's not obvious that a stereo WAV will only work on the two stereo channels but makes sense. There seems to be no way to play a tune except to inject it into a project? I was hoping to be able to play break music from the SDcard or a USB flash drive but can't figure out how?
I suspect that the headphones/speakers button reverse the phase on the ring contact so make sure you use the right position, especially on balanced input monitors!
I plugged a bass guitar directly into a channel. With the gain full up the distortion is "Cream" like and would be quite usable for that sound - not nasty like a Yamaha preamp. With the compression on full and the gain backed off to normal it's pretty punchy and useful for that kind of sound too.
Some things can only be accessed via the iPad app that connects via BlueTooth and requires a $30 Zoom BlueTooth dongle for the mixer. Range is limited to 10 meters and wo knows how it will perform in a room full of 2.4GHz devices?
#1 cool thing about this mixer is that it can record multitrack to an SDcard - no laptop or external drive needed! Also has SIX STEREO monitor mixes - wow!
It lacks any EQ on the 6 stereo monitor mixes so using floor monitors could be problematic. There is a 15 band GEQ on the main outs but you can only access it via the iPad app. The channel level meters are post-fader (yech) but I'm told you can change that in the app.