Aulos 521 knickstyle bass recorderIntroducing the Aulos 521 knickstyle bass recorder The 521 bass recorder from Aulos is designed for ensemble playing. It is pitched in F and its notes range from f (below middle C) to g'' (two octaves above). Being such a long instrument, the bass recorder can be a little uncomfortable to play, but Aulos have incoorporated an 'f bend' neck so that the player's arms don't have to stretch quite as far, and comparatively closely spaced keyholes for a