Besson Prodige 177 student E-flat tuba (silver)

In UK brass bands, the EE-flat (“double E-flat”) tuba is the standard full-sized E-flat bass instrument, with a compensating mechanism, large bore, wide bell, and four valves.

The single E-flat tuba is built at the same pitch but is more compact, lighter weight, three-valved, and has no compensating mechanism. This makes it popular with students or players who prefer a more manageable instrument.

The same distinction applies to B-flat tubas, where the full-sized compensating (‘double’) BB-flat models sit alongside smaller, non-compensating single B-flat student versions.

A compensating tuba has extra tubing that automatically keeps the lowest notes in tune, so players don’t have to work so hard with alternate fingerings or embouchure adjustments.

A non-compensating tuba doesn’t include this mechanism, but benefits from being lighter and easier to handle. More experienced players who prefer a compact instrument can still tune those low notes with a bit of technique and practice.

In practice, yes. Historically, some three-valve instruments included compensating tubing, but modern professional designs universally rely on a fourth valve.

The fourth valve both lowers the pitch by a perfect fourth and redirects air through the compensating loops, meaning these two functions are interdependent.

Today, all widely available four-valve tubas are compensating, while three-valve models are invariably non-compensating.