A mouthpiece includes a mouthpiece member having a bore, a flat upper portion, an air conduit formed by an inclined bottom wall, and a reed attached to the flat upper portion for partially shielding the air conduit, a barrier plate is extended from the front end portion for forming an included angle between the barrier plate and the inclined bottom wall, and for forming an air passage between the barrier plate and the flat upper portion, and for forming a tone-altering compartment between the barrier plate and the inclined bottom wall, and for forming a tone-altering chamber behind the barrier plate and for altering the tone or for echoing purposes. A partition may be extended between with the barrier plate and the inclined bottom wall.