I don’t like the metallic sound of the springs in the melodica.
To illustrate what I mean, here’s a quick recording with a noisy glissando without blowing into the melodica (listen with headphones or good speakers).
https://app.box.com/s/tneg2ubzcrr7kk52u1y6a5uh6e4m71nf
First melodica: Yamaha P37D, second melodica: Suzuki M-37C. The third melodica is a Thomann 37 Pro, where I’ve removed all reed plates (so it’s not the reeds that cause the metallic sound!).
The spring noise can be reduced by pressing and releasing the keys very gently. But I like the “tok” sound of the Suzuki keys, sometimes I want to use it to accentuate single notes. And when playing chords with two hands, pressing or releasing several keys at the same time inevitably sums up.
I’ve tried a couple of things to dampen the noise of the springs without affecting their springiness.
Self-adhesive sealing tape works very well, here’s how the Suzuki sounds now:
https://app.box.com/s/nfcq8t7rcc2exegt40h43epjsuyhzemp
And here’s how it looks:


I don’t know how durable this solution is, and hygiene in melodicas such as the Yamaha P37D, where moisture is released inside, might be an issue. Suggestions for improvement are very welcome!