A couple films explaining some of the lesser known and lesser used techniques and mutes for the tuba.
Tonguing with an open embouchure and banging the mouthpiece with the keys down are just some of the techniques discussed and explained in this film.
Tuba mutes are cone shaped objects that fit in the bell of the tuba. They come in two main types - plywood and metal. The image on the right shows a 'straight mute'. Mute (It. con sordina Germ. mit Dämpfer Fr. avec sourdine). It can take a long time to insert or remove a tuba mute. Composers be warned, John Jenkins hates using mutes in the orchestra! (And he's probably not the only tuba player out there who feels that way...)