What is the Optimal Separation Length for the Tines of a Tuning Fork?

I'm building tuning forks (for fun... why not?), and among one of the design decisions is how far apart should I place the tines (the two long prongs) from each other. I'm not entirely certain whether this has any effect at all (maybe except for very large or small lengths of separation), but is there an optimal length apart the tines should be to ensure that the tuning fork can function optimally? Does this length differ with frequency?

EDIT: As pointed out by @Keith McClary I would interpret "function optimally" as precise frequency.

1 Answer

It depends what you mean by "function optimally". If you want it to be loud, it must transfer energy to the air and thus it's vibrational energy must decay rapidly. Imagine that the tines are large thin vanes (close together) so they transfer most of their energy to the air in a few vibrations. You will not hear or measure a precise frequency.

If "function optimally" means a precise frequency, you want to minimise energy transfer to the air so that it rings for a long time.

This is a version of the "Uncertainty Principle" - you can't have a wave with short duration and also a narrow range of frequencies.

• Alright, so from what I've read, the tines should be farther apart, instead of closer together? Ok, but how far is far? Aug 19, 2015 at 1:57
• Aug 19, 2015 at 3:13
• OOps, I accidently hit enter and them editing timed out on me. I can't give you a number. I did a bit of Googling and found this Scientific paper and a page in this book. Don't you have some forks that you can compare to see which is optimal for you? Aug 19, 2015 at 3:33