Sound Post Down!

If you hear this sound inside your violin, viola, cello, or upright bass: don’t play it!

The sound post is supposed to stand up inside the instrument, so that it is in contact with both the top and back plates. It is not glued in place, so sometimes it falls, and then you will hear it rattling inside your instrument just like in this video. The sound post functions in both acoustics and structural support, so you can damage your instrument if you play without the sound post in place.