The Italian harpsichord did not change significantly over the centuries. It is a very light and linear instrument, intended primarily to support voices and instruments in much the same way as the Italian organ.
Thus, there was a need for a sound rich in overtones, supported by a pure fundamental, a rapid and even decay throughout the compass, and a precise and rather dry touch providing a lively articulation of the sounds.
The typical disposition of the italian harpsichord is one keyboard with two unison registers (8’8′); in instruments made before 1600, the second register is often at the higher octave (i.e 4′ pitch).
The usual compass is C/E (short octave) – c3, for instruments up to two metres in length, and GG-c3 for longer ones.
These Italian instruments may have an additional external case (“inner-outer”), or they may be constructed with a single case (“false inner-outer”).
The former are made with thin cypress sides and are very light (about 15 Kg) and are therefore rather fragile and not terribly stable: hence the need for an external protective and stabilizing outer case, often richly decorated.
The latter type, the “false inner-outer” instruments, have a stronger case, furnished inside with glued cypress stripes and mouldings that create the effect of an independent inner case.
G. Guami, Canzon Francese