Demakein: introducing --tweak-emission

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New version (0.15) of my woodwind instrument design software Demakein.

This version adds a flag --tweak-emission, which if set to a positive value tries to maximize the loudness of each note, in addition to making it in tune. The value determines the balance between these two possibly conflicting objectives.

Also in this version you can see the volume of sound emitted for each note from the end of the instrument and each hole. As expected most emission is from the holes, except for notes with all or most holes closed. This shows that bells on woodwind instruments are almost entirely decorative, especially so if they have tuning holes below the finger holes.

I had hoped that --tweak-emission would let me create nicely shaped bells on shawms. This was a total failure (see previous paragraph). However I think it is useful in discouraging Demakein from making abrupt changes in bore diameter. These are an impedance mismatch, causing a reflection from that point in the tube and hence less sound escaping the instrument in the end. It also provides a useful further optimization criterion when an instrument is otherwise under-constrained -- able to be fully in tune with some degrees of freedom left over.




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