Got mine today. Some clips are below. I've only used it with keys so far (EDIT: guitar comments added at the end), but in terms of first impressions:
1. Some of the simulations are pretty close - cello, strings, and voices. The sax and brass not so much. I have a M4000D and I did a quick comparison to the Mel9. Clip below. i went for the most similar patch I could find on the M4000D, not necessarily my favorite patch. Note in the brass comparison there is a patch that's pretty close to the Mel9, but then at the end I briefly played another patch on the M4000D that is much more natural sounding, just for contrast. And I don't have an "orchestra" patch on the M4000D, so I skipped that.
I divided the instruments between the left and right channels. The M4000D starts first for each instrument. And just for you folks, I ONLY played SFF for the flutes.
https://soundcloud.com/haassauce-1/ehx- ... ron-m4000d
2. It has some polyphony issues. It's not so much the number of notes, but the complexity of the chord. Anything with a half-step interval is problematic, as is a natural 7th. Sometimes it gurgles and sputters out, particularly with a half-step, and sometimes (particularly with a 7th) it generates a tone an octave lower in addition to the octave up, as though it is confused about the lower note you were already playing. I made a clip showing some of these issues. For most basic chords it doesn't have any issues though.
https://soundcloud.com/haassauce-1/ehx-mel9-polyphony
3. In terms of triggering and tracking, it can be a little touchy. I'm using a rhodes that's decently - but not perfectly - regulated. Volume variations that are fine with the natural sound of the rhodes can sometimes lead to drastically different levels (or no triggering at all) with the Mel9. Also, on lower notes, it takes a fraction of a second to catch the right note - see the beginning of the polyphony clip where there is a slight slur to the individual notes at the bottom.
Tracking clip:
https://soundcloud.com/haassauce-1/ehx-mel9-tracking
4. It sometimes has a high-pitched clicky-sound. You can hear that a lot in the polyphony clip. It's worse on the complex chords that seem to confuse it, but it also shows up in other places. And it doesn't seem to be clipping, because (a) the output level is at a normal instrument level that doesn't clip my other effects, and (b) it doesn't always happen at the beginning of a sound when it's loudest - sometimes it comes in after a second or so. I need to investigate this further.
Overall, a nice pedal so far within its limitations & design parameters. I don't really use these sounds to try to mimic the actual instruments, but more as an abstract/alternative voice, often manipulated through effects. I think for that type of use, it will be great. (E.g. if you hold quickly cycle through the rotary knob of voices while playing, you get some very interesting results.)
When I get another chance I'll see how it does on guitar.
EDIT: I had a little time to try it on guitar, but not to get any recordings. I think most of the issues noted above are still present on guitar, but not as prominent due to the nature of the instrument.
-If you play chords down low on the neck with a lot of close intervals, it will still gurgle and fizzle. But higher up on the neck it handles them better. You almost have to try to confuse it on guitar, whereas on keys (more simultaneous notes, easier to combine close intervals) you almost have to avoid it.
-tracking is about the same. on very low notes, you can still hear some 'slur' right as it grabs the note. but about the same speed overall as a POG or Ravish, as I suspected. interestingly, if you half-release a note, you can often get it to slur back down a little, like you pushed it flat.
-the high-pitched clicky noise is still there sometimes. not sure what that is.
-i wish the sustain control had more range on the low end. a mellotron has an extremely abrupt cut-off when you release a note, but on the Mel9 even with the sustain all the way down and muting notes as fast as possible, there is still a little decay. I noticed this on the rhodes, but thought maybe the dampers weren't muting the note fast enough, but it's the same on guitar.
-some instruments (i'm thinking of sax in particular) have a window on the neck where they sound pretty similar to the mellotron, and then outside that they get a little funky.
-from a overall playing perspective, i was left with the feeling that the pedal mated better with the guitar, but with a lot of interesting potential on both.
