I'd like to make the brass growl

[K.B.]

Please tell me how!

Bonus points to all who appreciate the thread title.

There must be hundreds, thousands of examples, but this is all I can think of at the moment (as I'm currently addicted): http://www.youtube.com/watch?v=UR0jn8B6iJk. Skip to 0:45 for the growling (edit: it's the trumpets I'm talking about).

Is that some form of muting (and manipulation of the muting device)?

Yes I know that I should know this, but I don't. Help is appreciated.

[DragonAvenger]

That's flutter tonguing. It's like rolling your R's while playing.

[K.B.]

Many thanks, DA!

I would never have guessed that (and would never have gotten close enough to google the answer). I am once again reminded of the many levels of ability above mine.

[Poke'G]

I'd just attempt to take its food bowl while it's eating.

...it works for dogs.

[K.B.]

I'd call that more a snarl.