Reply To: Bending Help

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#11091

Thanks!

I put only a tiny tiny drop of epoxy of the face of the reed near the tip and wait for it to dry completely before reassembling, but ya, I’ve thought about how wet epoxy could really mess things up.

I’ve been working on a theory on how bending works and why. Please tell me what you think:

For some reeds it’s simply a change in the size of the resonant cavity (the size of your mouth and throat) but for most others it seems to be a pressure change either drawing in both reeds slightly or blowing both reeds out slightly.

The reed is like the diagonal of a right triangle. The horizontal component of the triangle is the reed plate and the vertical component is the reed gap. During a draw the draw reed is sucked toward the hole and its angle decreases, increasing the horizontal component making the reed effectively longer and lower in tone. Also during a draw the blow reed is drawn further into the hole increasing its angle making the horizontal component shorter and higher in tone. The opposite happens during a blow bend: the draw reed is blown further out of the hole making the angle larger, the horizontal component shorter and higher in tone, while the blow reed is blown toward its reed plate making the angle smaller and the horizontal component longer and lower in tone. An alternative explanation is that as the angle on the reed increases the stiffer the spring becomes, making the tone higher. I’m not sure which explanation is correct, maybe both, but the result is the same.

When blow bending on hole 5 I initially go below E and make it all the way to D# before the blow reed resonance collapses and the draw reed takes over above F which I can then push to F# before its resonance starts to collapse and then both reeds start to go at the same time, cutting the pressure in half, and I have two notes going: one only half a semitone below E and the other only half a semitone above F. I see these two separate spikes on the frequency plot.

This theory also explains why I can’t seem to do much bending of any sort with the 7-10 holes because their reeds are so short and stiff that there just isn’t as much possibility for altering the natural angle of the reeds through simple pressure changes. It explains why a small reed gap on both reeds improves the ease of both draw bending and blow bending: it seals the hole more making pressure changes more important to the reeds.

Just some thoughts that have been going through my head while I practice, which is a lot more fun now. By the way, on a completely random note, my cats HATE my harmonica. Whenever I practice my cat immediately finds me and gets literally in my face to stop me from playing.

I have a macro lens on my camera. I could try uploading a picture of my altered reeds if you are interested.

Dave A