First, let's define some terms. If we accept the pitch generally referred to as middle C as being the lowest note on a standard 48 or 12-hole chromatic in the key of C, then the correct term for the lowest note on a 64 or 16-hole chromatic would be tenor C. The next octave below would be termed "baritone" C and below that again is bass C.
Michael Peloquin http://tinyurl.com/5tpjg http://www.harpsax.com