Sunday, August 26, 2007

Resonances and Overtones in Microphone Membranes

There have been a lot of discussions about the materials used for microphone membranes, capsules, ribbons, diaphragms etc. and also about how Roswellite tm fits into the widening range of improved materials that designers might use to make new microphones and transducers with.

Comments that keep coming up include the understandable questions "how does the new material sound"? Or, "What does the new material sound like?"

People are sometimes surprised that Roswellite tm mimics the traditional sound of "foils". How can it do that? Our old scientist friend Chladni explained how shape and frequency, and not material, influence the complex motion of acoustic surfaces such as drum heads, violins, and even microphone capsules. And of course we designed Roswellite tm to sound the same as before, because we have put so much effort into getting the sound in the first place. One variable at a time, please!

I've written a lot about Chladni and how important yet little-known his work is. His work explains why different ribbon materials can have the same timbre in a certain microphone, among many other things.

But you don't have to know about him to understand how the shape of mic element affects things like harmonic distortion, tizz, and breakup.

You can click on this link and see graphically what shape does to the nodes and antinodes on a surface.

For ribbons, select rectangle. Enter 1, then 30. This will give you a graphic of the pattern on a long skinny ribbon or skinny plate.

For round elements, select circle, and enter any two same number such as 1 and 1.

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