My P37D Suzuki has been modified with 2 pickups by the good folks at Heyday Music in Asheville NC. He doesn’t remember exactly what he used, but there are 2 piezo disks, about 3/4 inch across, in parallel. He says they are the kind security people put on windows to sense vibrations. He placed them on the plastic that covers the reeds, one by the low e, and the other by the high g. Then I ran it through a Steinberg interface and put a bit of stock reverb from Reaper on it. I did not EQ the melodicas.
This recording is all me; AND we have a melodica band (Next Road Over) of 5 here in Western North Carolina. Fran, who played bass on the recent Monsters of Melodica project is in the band. We also have a group of about 12 people who get together 2-3 times a month to play. Come sit in with us!