Does pressure affect sound waves

The speed of sound changes clearly with temperature, a little bit with humidity - but not with air pressure (atmospheric pressure).

The Words "sound pressure at sea level" are incorrect and misleading in the case of "speed of sound". The temperature indication, however, is absolutely necessary.

The changing of atmospheric pressure does not change the sound of Musical Instruments in a concert hall or in a room; see link: "Speed of Sound in Air and the effective Temperature".