 All instruments are chromatic down to E2, but four-valved instruments extend that down to at least C2.Non-compensating four-valved instruments suffer from intonation problems from E2 down to C2 and cannot produce the low B1; compensating instruments do not have such intonation problems and can play the low B1.From B1 down lies the "pedal range", i.e., the fundamentals of the instrument's harmonic series.