Glass Knowledge

Tuesday, March 5, 2013

I’m always surprised when I realize I have a knowledge set that not many other folks have. A percussionist friend of mine, Dave Shively from Either/Or Ensemble, emailed me yesterday asking about low pitched glass bowls. Here is my reply.

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Hi Dave!

You’ve come to the right place. Those are actually reasonable pitches for low glass. But the trick is not only large size but also the thinness of the glass itself. A medium sized, thin rimmed brandy snifter will usually vibrate slower (lower) than anything larger and medium rimmed.

Brandy snifters are usually a good shape, or those “bubble bowls.” You can find large ones at floral supply places. And a good thing about tuning glass is the pitch gets lower the more water you put in ‘em. With those large ones you can usually tune down about a maj3 from the dry pitch. Although the less glass actually vibrating (meaning the more water), the quieter it gets and the pitch starts to wobble.

When you say “sustained friction” you mean you will be finger-bowing the rim, right? I’d recommend staying away from lead-crystal; I find the tone to be too bright. Plus the lead can bleach into your body pretty quickly at the fingertip. Plain old silica glass would be the way to go. But you do need to make sure it has a steady pitch. With some vessels the pitch can really wobble as you rub around the rim.

The ideal music glass is quartz crystal. Beautiful pure long tone, but very pricey.

You can probably find nice sized brandy snifters at Crate & Barrel, but if you want to go the floral supply route, check out Jamali Garden on 28th between 6th and 7th ave. I think that’s the place where I last found a good large bowl.

Good luck! If you can’t find anything that works, I can check my own collection.

best,
Miguel

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Of course, I had much more information I could have shared, particularly about how glass vessels that vibrate in close proximity to one another over a long period of time will actually be influenced by the others’ frequencies and change pitch ever so lightly to a simpler harmonic ratio. In other words, they will tune themselves.

But that’s a bit more esoteric than the basic information Dave wanted.

I was recently asked to contribute a couple of pieces to the Leonardo Music Journal on the subjects of acoustics. You can hear them here and here.

{ 2 comments… read them below or add one }

Man From Glass March 6, 2013 at 10:00 am

Hey Mr Miguel,
You are being controversial! Seems the jury is out on whether lead from crystal can actually be absorbed through the skin. You’re probably remembering the glass armonica issues. I think I read somewhere that the problem wasn’t the glass itself, it was the lead based paint that was used to mark the accidentals. Another useless bit of trivia – if you have too much lead in your system your teeth go green. This happened to pre 20th century painters. My memory cells may be mis-firing but you can see in some of Caravaggio’s paintings of self portraits that he paints his teeth as being green and rather gross. DNA testing found very high levels of lead in his bones.

Miguel March 8, 2013 at 5:53 pm

Ah, that’s new information to me, Eric. I guess I should have said, “IF the lead in glass bleaches in the body it would do so faster at the fingertip since that is where everything is closer to the surface,” or something like that. But wait a minute, aren’t you the guy who refused for years to finger-bow ANY glass because you were concerned for your, uhm…., shall we say, virility!?

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