Last summer, I repacked my D&D which are known for their ungodly loud noise! With some industrial furnace insulation and bronze wool. The insulation is much more dense than the original stuff, wrapped, taped, and re-wrapped and taped. The result is what has to be the quietest D&D you will ever hear! Still has a nice deep tone, but very quiet. It cost only about $25.00 with enough material left over to repack it again!