Adjustable “high note” modification for Fox Contrabassoons

The original keywork from the factory.

Here’s a cool contrabassoon mod which lets you adjust for high notes “on the fly” without having to add cork or bend any keys whenever you need to play high note passages. Essentially this creates a “half hole” whenever you press the left hand second finger without the first finger.

In their own fingering chart, Fox describes a “modification” to the keywork which makes playing the highest notes on the contrabassoon much easier. I believe this was written by Chip Owen: “For very high notes a special key adjustment¬† is required. Adjust arm 913.5 so that pad 911 does not quite closed when 913 is closed. The amount of leakage should be small.¬† Pads 909 and, 911 must close together perfectly. The leakage on 911 not only plays the high notes but will also benefit the octave F# and G.”

This is all well and good, but what if you want to adjust the amount of leakage? Or even get rid of it altogether when its not needed? The answer is found on just about every oboe that’s been made in the last 100 years. Oboe keywork contains a handy way to adjust the relative levels of keys using a small threaded flathead nut.

Closeup of modified key, with adjustable screw added

I took one of these adjustable keys off of an oboe, and soldered it in place on linkage 913.5! Now I’ve got a tiny bit of an oboe on my contra, but I can adjust the “half hole” whenever I need to.

Repair people, feel free to contact me below for specifics about which oboe keys to use and the other subtleties that make this mod a success.

Note: some notes (like high Eb) are negatively impacted by this adjustment, but ample alternate fingerings exist to get around this and still realize the benefits of much easier high notes.

The final mod!

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