I recently purchased the lefreQue system for bassoon. I have to say that in a week of testing, I am quite satisfied and surprised by the results I'm getting.
What is the lefreQue?
The lefreQue is a system of metal plates that go over the connections on the bassoon which are either cork or thread. Plates go from the bocal to the wing joint, the wing joint to the boot, the long joint to the boot, and the long joint to the bell. The plates are available in a variety of metals: brass, red brass, silver plated, solid silver, and gold plated. I purchased the silver plated lefreQues--there is an option to do a solid silver at the bocal connection, but I felt that reed adjustments could be made to capitalize on the lefreQue system, so silver plated it was!
What is it supposed to do?
In theory, the cork/thread on each of the tenons and on the bocal deaden the vibrations that go through the wood. It makes sense when you think about it, really. The overtones in the entire spectrum are supposed to improve greatly.
How did I connect it to my bassoon?
I purchased all 4 recommended connections: bell, bocal, wing, tenor. I've attached them like this...
Wing & Boot
My initial reactions
Overall I am impressed with the lefreQue system. I would say that if you are having issues with fatigue, erratic intonation, or thin sound, you ought to give it a try!