I appreciate your appreciation of my endeavors to explore the expressive capabilities of the melodica.
Here are some ways to bend notes. Some of these are specific to out-of-production Hohner Piano 26/27/32 melodicas. In other words, some of these techniques will simply not work on other brands of melodica due to differences in design.
In my experience, bending notes on Piano 26/27/32s Hohners is much easier than any other brand of melodicas. In addition, just like harmonicas, certain notes bend more and are easier to bend than other notes. Generally speaking, lower notes are easier to bend than higher notes. It is almost impossible to bend very high notes, though a few of us that visit this site have managed to develop techniques to do so.
Ways to bend a note on a melodica:
1. Blow hard. Easiest and fasted way to bend a note. Easiest and fastest way to ruin your melodica. WARNING: blow too hard and you will damage your reeds. Once damaged, a reed will bend too easy, making your melodica sound out of tune at playing volumes. You will have to ruin several melodicas or replace several reed plates before you figure out how hard is hard enough.
2. Damage a couple of reeds. Once damaged, you have nothing to lose. You now have a melodica that can achieve pretty deep bends on those notes with damaged reeds. However, you must play those notes pretty softly when you are not bending them or they will sound far out of tune. So a melodica “prepared” this way will have to be used in specific keys to achieve the bends on the right notes.
3. Depress a key only slightly while blowing. This will work but requires such precision that it does not seem practical to me during performance.
4. When trying to bend a note using blowing pressure, wave the melodica around to accentuate the bending with the Doppler effect and centrifugal force. From http://www.physicsclassroom.com: “The Doppler effect can be described as the effect produced by a moving source of waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching and an apparent downward shift in frequency for observers from whom the source is receding.”
A Leslie speaker cabinet with its horn rotating on slow speed provides a pretty significant Doppler effect, which is its goal. I can move my melodicas much faster through the air than a Leslie rotor on slow speed. The audience and a stationary microphone pick up this effect more than the player does I do believe.
Centrifugal force? I believe it contributes, but I have no evidence. Yet my instincts and what I hear keep me believing that it helps accentuate bends on the lowest notes with the largest, heaviest reeds. Putting blowing pressure, Doppler effect and centrifugal force together is not easy. I have not perfected it yet, but I have had momentary success with huge bends.
5. Using Piano 26/27/32s with the sound holes on the back, press the back of the melodica into your chest to seal off most of the air flow. Blow into the melodica while holding down a note. The flow path upstream and downstream from the reed is pressurized, with the reed sounding in some funky way from the little bit of air that is getting through. When you release the melodica from your chest, the release of pressure and rush of air through the reed will make it bend.
All kinds of funky sounds are emitted from these melodicas when you pressurize them and unpressurized them using the above technique. Variables are shirt material, level of sealing, area of sealing, how fast and how far you release the melodica from your chest, and much more. Using this technique, I can bend high notes and low notes without using excessive pressure, and I can get reeds to sound in sympathy with other reeds.
6. Buy a pitch bender pedal.
I think there are some other techniques that are not coming to mind right now. But that should get you started.