The double bass has a phenomenal range due to the length of its strings, but there are some limitations. The strongest register, of course, is the first octave and a 5th – the instrument was essentially built specifically to access those notes.
The next octave is not so strong – the effort involved in playing higher notes in tune, plus the obvious superiority of cellos and violas, makes that register a rare one for basses, though not unheard-of. However, it’s actually a quite effective, ethereal range for a soloist. Here we get into the subject of yesterday’s tip – the notes from written middle C and up reveal the character of the double bass very strongly as a member of the viol family. Therefore, any notes played by a soloist must be very carefully accompanied, especially by the violas, whose tone will easily swallow the bass’s whether they’re playing solo or as a section.
As a section, the basses can range up to G above written middle C safely, if the rest of the strings are absent or are in a higher register – but use caution, and ensure that this makes sense timbrally. Also, approach this register by step rather than leap for the best results.
The double bass’s range can be pushed even higher by harmonics – not false harmonics, which the string length makes mostly impracticable – but by natural harmonics, very abundant and easy to access.
Now, even though these higher registers are admittedly weak by comparison to the other, more forceful members of the string section, there’s no doubting that the resonant cavity of the bass’s body lends a certain unique projection and presence to such tones. The bass can be very effective as a solo instrument, and more concertos should be written for it. As for bass solo or basses soli within a general orchestral piece, sparingly is the key to enchantment, rather than aggravation for the listener.
In the following excerpt from the solo part of my double bass concerto (ha! NOT the harp concerto this time!), I cover the full possible range of the bass, ascending from bottom open E all the way up to B above the treble staff. Note how the approach maximizes the lyrical potential of each register: widely-spaced intervals in the bass staff; more circular lyricism in tenor clef; and slow, deliberately placed harmonics at the top. It’s an approach that allows for a very dramatic arc, one that can be developed and magnified.