Detection system and musical instrument

A musical instrument comprising:

• a first movable member and a second movable member that move in response to a playing operation of a user;
• a first detectable coil disposed on the first movable member;
• a second detectable coil disposed on the second movable member;
• a first signal generator, including a first drive coil that faces the first detectable coil, configured to generate a first detection signal based on a distance between the first detectable coil and the first drive coil;
• and
• a second signal generator, including a second drive coil that faces the second detectable coil, configured to generate a second detection signal based on a distance between the second detectable coil and the second drive coil,
• wherein the first drive coil includes:
• a first driver through which current flows in a first direction;
• and
• a second driver through which current flows in a second direction opposite to the first direction,
• wherein the second drive coil includes:
• a third driver through which current flows in the first direction;
• and
• a fourth driver through which current flows in the first direction,
• wherein the first detectable coil includes a first portion and a second portion where induced currents in directions opposite to each other are generated by electromagnetic induction of the first drive coil, and
• wherein the second detectable coil includes a third portion and a fourth portion where induced currents in a same direction as each other are generated by electromagnetic induction of the second drive coil.