I would like to begin by stating that my trompette technique is by no means the only way to accurately achieve the coup de quatre. Many excellent players hold the knob quite firmly at all times.
In addition to this workshop, Scott Gayman has produced a great set of youtube videos covering all aspects of playing the trompette. They can be accessed <<<here>>>
The following photos will I hope go some way to clarifying the basic philosophy. ( I have purposely left my hand rather more open than usual to make things clearer ).
" The hand should be held like a little cage for a little bird " Maxou Heintzen
|The first coup is made by contacting the knob with the thumb joint. It can be useful to rotate the wrist anti-clockwise momentarily to accelerate the knob . The wrist is never to be allowed to flex downwards.
|The second coup entails pulling back with the index and middle fingers coupled with forearm movement.
|The third coup uses the base of the "cage" created with the curled in 3rd and 4th fingers. It can be useful here to rotate the wrist clockwise momentarily. The wrist is never to be allowed to flex upwards.
|The fourth coup tends to be the trickiest and is achieved by a push from the forearm. The knob contacts at the base of the thumb.To repeat the rhythm, the knob rolls up the thumb into the joint and all is repeated.
|The actual coup is not applied in the direction of rotation
but rather inwards towards the axle and is applied just after the point at
which the knob and axle are in line with the hand.
If the coup is made too early, the hand, knob and axle will all be in line and nothing happens, too late and the mechanical advantage is lost .
To further explain my theory of the mechanics of the trompette, the following diagram may help:
The contact points of the hand dictate exactly where in the rotation the coup must be applied.
Practice making coups 1 & 3 give short crisp buzzes to allow time for 2 & 4 to be played.
Ideally, pick tunes which you have not played before lest previous bad habits prevail !