The contrabass/double bass in almost all orchestral libraries will be transposed by an octave. This makes it easier to reuse the notes played by other instruments such as the cellos, bassoon and french horns (which is transposed one octave lower).
The contrabass/double bass in almost all orchestral libraries will be transposed by an octave. This makes it easier to reuse the notes played by other instruments such as the cellos, bassoon and french horns (which is transposed one octave lower).