Fill in the Blanks Musical InstrumentsOnline version An activity related to musical instruments that is sure to delight everyone! by Paul Soper 1 brass first trombone arms seven trombones glissando tube slide timbre seventh trigger The best instrument in the family is the . Not only does it have a beautiful , rich , mellow , it is the only instrument to use a . This mechanism is made up of positions allowing the player to from a mid - range B flat in position down to a low B natural in position . For those whose can´t reach that far , modern now come with a which allows players to change the length of the and low B natural can now be played in first position . How convenient !