Clutch Diaphragms

Since I posted the MR video at the beginning of the year, I have had several questions about the four metal discs that are hanging on the right side of the set. I realized that I have not posted about them yet, so here it goes.

The flower like metal discs that are hanging on the right side of the MR drum set are pressure plate diaphragms.  When a clutch goes bad on a manual transmission car the clutch disc and the pressure plate need to be replaced.  I originally started saving pressure plates as possible hi-hats, but after disassembling one I found that the diaphragm had a very unique and cool sound. 




Front view of an intact pressure plate



Rear view

It takes some cutting and grinding to seperate the pressure plate.  Once it is apart there are three main peices.  The pressure plate housing, the disc, and the diaphragm.  The three parts are shown in the picture below.

The diaphragm or spring plate is the most melodic part of the three.  They have a very unique sound, and I have found many different pitches depending on the size of the diaphragms.  They are very sensitive to how they are suspended, and I have found a brass mallet produces the best tone quality.


Diaphragm



I have not found any use for the pressure plate housing (yet), so for now they go in the scrap metal bin.

Pressure plate housing

This piece of the pressure plate has surprised me the most.  The pressure plate disc sounds a lot like a muted anvil or metal plate.  Each of these pieces also have seperate pitches depending on the size and thickness of the metal.

Pressure plate disc

Here is a short video of different sounds from the parts of a clutch pressure plate.