Posted by Joe B on September 13, 1999 at 12:54:10:
In Reply to: Strange phenomenon posted by Ian Easton on September 10, 1999 at 04:28:04:
1) By 'half-valving', you cross the intermediate pitches without any help in resonance from the horn to 'slot' your pitch. As such, as another poster said, you simply gliss to your destination and are already producing that pitch when the resonance kicks in.
2) By opening up all that extra tubing, you suddenly hit resistance with air (quite a bit in third valve tubing) that is not moving. You have to suddenly overcome the inertia of that air at rest (and compress it), which will momentarily cause a loss in air speed when you are trying to move to a higher partial that requires faster air speed. This seems the most likely cause of the problem, but doesn't explain why slow valves improve things.