These exercises are from Arnold Jacobs' Special Studies for the Tuba (and Euphonium) and includes his Scale Studies exercise and his Development of Low Register and Resonance exercise.

The Scale Studies are available in 3 tempi [80, 100, and 120 BPM] and take the player through all 12 major keys and utilize a variety of articulation patterns (that were added by the creator of these backing tracks, Dr. Brett Copeland).

The Development of Low Register and Resonance is available in few different keys, starting with the original key for the exercise of Eb, and is expanded up to F# and down to C.

Included with this download is a .pdf of both the Scale Studies and the Development of Low Register and Resonance (in all available keys).
 

As a BONUS I've included my Scale Studies Packet that includes my favorite scale and chord exercises for all 12 major keys.
 

ENJOY!