Tiens j'ai l'explication mais en anglais: en fait ce bouton sert a calibrer l'accordeur incorpore dans ton preamp. Plus tu appuies dessus plus la hauteur de reference monte jusqu'a 445 Hz, puis redescend et commence a 438Hz. Le La de reference est a 440Hz. Voila si parle l'anglais tu as l'explication en dessous.
When the Pitch button is pressed, the frequency that is currently set will be shown by a flashing red light above the frequency number. While the reference light is flashing, press the Pitch repeatedly to set the desired reference pitch. With each press of the button, the reference pitch will increase by 1Hz increments from 440Hz to 445Hz. Once the pitch has reached 445Hz, the next press will decrease the pitch to 438Hz. When the button operation is stopped, the reference pitch is set and the tuner will stand by for tuning.
Un jour Miles (Davis) en plein milieu d'une repetition est alle murmurer a Jack Dejohnette: "Boom.... Boomdiboom...OK?". Jack n'a pas du tout compris ce que Miles voulait lui dire, mais ensuite il a joue completement differement. John Mclaughlin (traduction approximative signee Multiac lol!)