More on Resonator Tuning
I did the first round of resonator tuning "by ear".
Using a bucket of water to stop off the end of the tube I changed the water
level until I got what seemed like the best sound. After making all the resonators
I discovered I could measure the tuning of the tubes with the strobe by placing
a microphone at the opening and taping the end cap. Most were tuned 15 - 40
cents sharp, but my "best note" had a resonator tuned 80 cents sharp!
One of the "worst note" resonators was tuned 15 cents flat, (shortening
it made a noticeable difference). I can understand the general finding of 15
- 40 cents sharp, since the functioning length of the tube includes the distance
between the bar and the tube opening, but 80 cents sharp, that seemed a bit
extreme. One of the great things about the overall design of this marimba is
it's modular nature. I can make a new resonator (or note), easily install it
on the instrument, then change back and forth, the old and new. Radically sharp
resonators (70 to 90 cents) give a slightly punchier sound. But one would think
that they would hardly work at all. Why is resonator tuning so approximate?
I'm still pondering this one.