Round, calm, hearty, loud, robust, ponderous, sustaining, soothing, earthy, sonorous, majestic, cavernous, rumbling, unfathomable, grave, weighty, broad, resonant.
In all registers the tone is richer, rounder and darker than the bass tuba and less metallic than the bass and contrabass trombones.
A0 – Bb1
The pedal notes sound earthy, rumbling and unfathomable; it is difficult to tell what their exact pitch is. These notes are generally doubled an octave above.
The higher notes in this register (from B0–Bb1) correspond to the 2nd naturals and are very sonorous, hearty, majestic and sustaining. It is the notes within this compass that are used most often.
B1 – Bb2
A continuation of the low register (naturals 3 and 4). Below F2 the tone is the typical contrabass tuba sound, above it it sounds like a tuba in F.
B2 – Bb3
Very powerful sound which can easily produce an imbalance in the overall sound when played forte. In this register the tone is rather thick and lacks metallic or brilliant properties. The bass tuba is often used for this range.