Baroque Tenors may be made either with only open holes for low C and C#
and no keys, or with keys on the foot joint for low C and C#. In
general, keyless tenors are on the smaller side in order to place the
holes where they can be reached. They often have a sweet sound
reminiscent of a voiceflute, but less volume in the lower register.
Keyed tenors are usually a bit longer and with a larger bore on the
lower end (with the exception of the Moeck Rottenburgh, where the
version with keys is the same size as the version without), which gives
them more volume in the low range.