Adam & Weast Test Results

Experiments can be setup to prove something, to disprove something or to find out something.A trumpet professor at Indiana U, Bill Adam, did some experiments a few years ago with an air gun. He stretched a piece of leather and secured it very tightly over the mouthpiece of a trumpet.

He then poked a tiny hole in the center which serves as the aperture. Then he used a compressor which blows highly accelerated air across the hole in the leather.

He said it produced an extremely loud and high note, much like an air horn.

He concluded that the sound produced by a trumpet is the result of sympathetic vibrations that are setup in the tubing. The more the air is accelerated the easier it should be to produce high notes.

Mr. Adam did a great deal for trumpet playing but he was not using good scientific principles. Mr. Adam was trying to prove that embouchure is not as important as air.

He did prove that a note can be produced through an open hole.

He did NOT prove it is impossible to buzz and play or which is more efficient.

In 1962 Robert Weast did some studies with a machine that blew pressurized air through rubber lips that were under tension.

The amounts of pressure do NOT compare with what we encounter. But the general findings do.

Using 5 oz of air pressure (oz/si) these notes were produced:

Ab ( 1 oz of membrane tension),

A ( 2 oz of membrane tension),

Bb ( 5 oz of membrane tension),

B ( 6 oz of membrane tension),

C ( 7 oz of membrane tension),

D ( 8 oz of membrane tension).

Although both open and closed produce notes. Open needs more air than closed. Closed with the same airspeed as open gives a higher note.

The D could be produced with:

14 oz of air @ 1 oz of tension,

13 oz of air @ 2 oz of tension,

12 oz of air @ 5 oz of tension,

9 oz of air @ 6 oz of tension,

7 oz of air @ 7 oz of tension,

5 oz of air @ 8 oz of tension.

He had NO way to add lip compression. He could make the hole bigger and smaller by tension alone.

The looser lip setting required more air pressure to play higher notes.

Don’t confuse tension with compression. Lips CAN be compressed but relaxed and they CAN be tense and open.


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