Monday, January 10, 2011

Glockenspiel Keys


Here are the first few keys for my glockenspiel. I crept up on the finished lengths of the first two bars, taking 0.1mm increments and measuring frequency. With the remaining six I put my trust the physics and was surprised by how well tuned they turned out.

For those interested in the physics, the ratio of frequencies differing by a semitone is 2^(1/12).
Also the fundamental frequency of a bar is inversely proportional to the square of its length.

Thus the ratio of bar length between semitones is (2^(1/12))^(1/2) = 2^(1/24).

For example if it is known that say a bar tuned to C is 200mm long then a bar tuned to C# is given by:

Length(C#) = Length(C) / 2^(1/24)
Length(C#) = 200 / 2^(1/24) = 194.31

3 comments:

  1. which material are the keys ?? sounds Great!!

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    Replies
    1. Hi Jennifer,

      The keys are aluminium, this is an easy material to work with. However the resultant sound had a very high pitch.
      For a more pleasant sound steel is a good option. Traditional glockenspiels use steel bars.

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  2. Hello, I'm interested in building a glockenspiel from scratch. this article is very helpfull. Though I was thinking of using aluminum but read your above recommendation. Is steel harder to work with? I guess it is, but still want to ask.

    also the first C note with what length did you begin with?

    thank you in advance, any help will be trully appreciated

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