I was listening to some JS Bach harpsichord pieces, and it seems to me that they run faster than piano pieces. I know that the harpsichord is constructed differently than the piano-its strings are plucked, not stuck by hammers (as in the piano). Does this mean that the harpsichord can be played faster? Incidentally, are odern harpsichords made today? Or are they renovated old instruments?
Yes, harpsichords are still made. Don’t know about the rest.
I am NOT a piano player - but I am a musician and read a few books on piano construction (Steinway: The making of a grand piano is really good).
Anyway - my guess: a hammer striking strings is going to have a faster response time vs. a plucker plucking a string on a harpsichord. Also, I believe the move to piano was driven by the fact that a piano is more “touch-dynamic” - that would suggest it is more responsive and could be driven faster. I think a piano’s mechanism from pushed key to sounded note is simpler…
I would further guess that, for want of a better term “harpsichords sound faster” - meaning that the arpeggios and other flourishy approaches used make them sound faster, but a piano is ultimately more responsive device.
Horowitz just about broke the sound barrier playing triplets on a piano. There’s a jazz player I love named Red Garland - he plays these triplet clusters so fast and with such consistently that he establishes a sonic landscape with them - that’s a level of speed and responsiveness that I think outdoes what a harpsichord could do…
Where is Le Ministre or some of the other players out there? I will be interested if I got any of this close to correct…
Hmm, gotta ping pulykamell - he’s a keyboardist, but don’t know if he has experience on real harpsichords…
I’ve only played the harpsichord a couple of times, but it does have a much lighter action (although the action gets heavier as you add stops–basically engaging additional or different strings-to it) and the keys are smaller. I would personally say that the hammer action of a piano is more responsive, especially when playing single notes in quick repetition.
However, the lighter keyboard touch and smaller keys do kind of give you the illusion of being able to play faster. (At least they seemed to me to do.) But I think it’s an illusion. Playing repeating single notes, for instance, is much easier with a piano’s hammer action.
I think most of what you’re hearing in the JS Bach pieces is the type of music that is created for harpsichord, which tends to be more ornamental and more flourished with runs and arpeggios. The reason is you need that movement to sustain and fill out the sound. The harpsichord is a plucked instrument whose strings decay quite quickly. It’s not like a piano where you can bang on a chord and hold it for several seconds before it decays. So you kind of have to compose with “busier” melodic and harmonic parts to keep things interesting and the sonic space full, if that makes any sense.
Okay then: what he said. 
Remember, that’s my impression from playing it a handful of times (maybe a dozen at the most–our church’s rehearsal space had an out-of-tune harpsichord that I’d sometimes bang on for fun.) There’s gotta be someone here who plays both regularly who can give a more in-depth assessment.