I've just spent the weekend tuning brass reeds from an organ. It sounds like a very similar process, except you can grind both ends of the tongue to raise and lower frequency.
Funny you should mention that another hobby of mine was rescuing old harmoniums and making them playable again—you know, fixing and replacing reeds, renewing bug-eaten felt, sealing rat holes in the bellows, etc.
I grant you it's not in the same league as voicing a diapason though. :-)
I reckon adjusting and tweaking things goes with the territory. I'm pretty much at home tweaking crystals, fixing reeds, aligning IF stages in radio and TV equipment, there's much of a sameness in the way one tackles all of them.
BTW, I've actually repaired reeds by soldering them. Not a good fix as the solder can fatigue with use. Throws out equal temperament a bit too but most can't hear the difference.
Oh that is so cool. I played the one in Liepaja, Latvia for a bit and it was absolutely amazing. It's love/hate for me (like the harpsichord), I love the instruments but I usually do not like the music that is played on them because of the grating effect. I have pretty bad tinnitus which really spoils a lot of music for me, extremely annoying.
Adding solder has also been frequently used to correct the resonance frequency of quartz crystals that have been ground too much, and I mean during industrial mass-production, not only in a home-lab setting.
How are people sticking stuff to quartz? I know less than nothing, but the pieces of quartz you find in rock don't look like they'd take a solder bond.
I'd assumed that with piezo crystals etc there was a mechanical connection rather than an electrode bonded to the crystal?
But if you can add solder presumably there is some kind of molecular connection with the metal?
Electrodes are deposited on the crystal in vacuum, e.g. by metal evaporation or sputtering, in the same way as they are deposited on the semiconductor crystals used to make transistors or integrated circuits.
The electrodes may consist of multiple layers, a base layer that adheres strongly to quartz and a top layer that is solderable, e.g. made of nickel or silver.
The pins of the package that hosts the crystal resonator are soldered on the electrodes, in places well chosen so that they will not damp much the oscillations of the crystal.
When the mass of the crystal must be increased to shift the resonance frequency, excess solder may be deposited on the electrodes.
There is already a silver patch bonded to the crystal where the wire connects to. Adding weight to that obviously will not make the load curve any better but if you do it with just enough to drop you back down below where you wanted to be then it can be a saving move. You could also put a trimmer in parallel, but that might not have enough range (and can also end up overloading the crystal so the oscillator won't start).
