Zero Level
This is a standard reference audio level used when discussing relative levels. Commonly the zero level is chosen to be 1 mW. This corresponds to 0.775 volts rms across a 600 Ohm resistance.

Musical instrument composed of strings mounted upon a resonate frame, strings can be plucked with fingers or struck using small mallets.

When a songwriter dies, the minute you read the list of songs he wrote, you start to identify with him - "Oh, my God, he wrote that. I remember the first time I heard that song, I was at a dance with a girl."”
  Abel Green