QUOTE(spaceman @ Apr 21 2007, 03:28 PM)

QUOTE(JudithJ @ Apr 20 2007, 01:44 PM)

On an acoustic the strings for the lower notes are thicker than those for the higher notes. This means that you have to press the key slightly harder for a low note than for a high note in order to obtain the same volume. A good digital will replicate this difference.
On a grand piano, at least, it's more than just that. You actually have to use more force just to get the piano key to move for the lower notes. My piano teacher showed me a graph his tuner had made for his Steinway grand which showed how the force required changed across the keyboard. (The tuner had actually measured this for his piano.) So, any digital keyboard which wants to replicate that properly needs to actually have a
physical difference in the keys, not just a change in the velocity response in the software.
That's interesting, I didn't know that.
I played a number of different digitals before I bought mine. My favourite (which was far out of my price range) was the Yamaha GT20. It was half way between an acoustic and a digital. It looked, felt and sounded like an acoustic - but you could use it with headphones. It had an acoustic frame, keyboard and hammers, but no strings. The movement of the hammers was converted into digital by a series of laser beams. You could then either use the headphones or the built in speakers. Speakers were placed at judicious points within the piano to replicate where the strings produce sound, the sound then used the piano as a sound box in the same way that the strings do.
It was an absolute delight. I wish that I had the money to buy one. If I had then I don't think that I would have felt the need to buy my acoustic a few years down the line.