response 14 of 19:

Apr 25 15:38 UTC 2002

The harpsichord has been played in tempered intonation since (and before) 
Bach's "Well Tempered Clavier".  (A clavier is any keyboard instrument.) 

I don't know what "hammered metal bars" are, but the clavichord is a
stringed instrument, except the strings are struck from the side by metal
bars (tangents) raised by the keys.