 Together, the bass bar and sound post transfer the strings' vibrations to the top (front) of the instrument (and to a lesser extent the back), acting as a diaphragm to produce the instrument's sound.Cellos are constructed and repaired using hide glue, which is strong but reversible, allowing for disassembly when needed.Tops may be glued on with diluted glue, since some repairs call for the removal of the top.