This video covers How the Anakin and Darth vader Hasbro Lightsabers ($20 version) sound, how to take them apart, and the dimensions of the soundboard.
This is a custom saber designed by my son. He is 4. It is made from various MR parts with a BIN 1 Cyan Luxeon III LED and a Hasbro clone wars soundboard.
The hilt is a Saberforge 2011 Redeemer with a green seoul p4, just improved the finish... also drilled a few holes in the emitter and added 2 buttons/switches on ...