It’s a very interesting question how much different mouthpieces influence the sound of the melodica – at least interesting enough to do some experiments…
I took my Labourdette and recorded a short melody using the following mouthpieces:
1. No mouthpiece
2. Labourdette clarinet-style mouthpiece
3. Suzuki MP-141 mouthpiece
4. Suzuki Andes MP-151 mouthpiece
5. Suzuki tube MP-113
While blowing into the mouthpieces keeping them tightly closed (without losing air at the side) I certainly could hear differences during the recording – and so I was quite surprised when I listened to the track afterwards and didn’t notice ANY difference at all. I strongly suspect that hearing these differences is a personal impression depending on the position of the melodica while playing with mouthpieces of different lengths and depending on how much I like certain mouthpieces at all.
But does that mean that we need different mouthpieces only for our convenience? I continued with my experiment and recorded a second track with a more open position of my lips so that some air could flow out at the side; and suddenly the differences were clearly audible, the more air I let flow at the side the more pronounced the differences became, up to nearly whistlings sounds…
And if now I would do what you did, Jazzman, and nearly talk into the instrument while playing the differences would be even bigger from mouthpiece to mouthpiece!
Here’s the recordings:
Labourdette_different mouthpieces