Does anybody know for a fact that the Roland FP3's basic Grand Piano 1 is the same as the FP5's basic Grand Piano 1 sound? Do they have the same clarity and behave the same way? Or are they different, did it get improved on the FP5?

I have NOT compared the two directly. However, I can offer the following:

Because different models are designed and manufactured at different times, there are often sonic differences even among patches that are based on the same samples. This is mainly due to the use of different parts during manufacturing.

One real-life example is the now discontinued Roland XP80 and JV1080. Both are capable of playing JV series expansion boards. I once did a studio session where I used a Hammond organ sound from an expansion card. I was quite familiar with the sound as I used it frequently on my XP80. This time, however, I wanted to have it play from the JV1080. I was shocked to hear the difference!!! The XP80 sounded much better than the JV1080 while playing the exact same patch!!! However, my XV5080 sounds better than either one using the same expansion board!!! Now it's easy to hear the difference in a recording studio. In "real life" -- that's another story!!!

So my point is that these are subtle differences that may or may not be perceptible in your environment (depending on amp, speakers, etc.). It may sound overly simple, but my best advice is to use your ears.

I know what you mean. I have also noticed that modules can behave and sound different when using different controllers with them rather than playing an onboard sound directly. Sound engines, action interfaces, A/D converters and audio outputs vary.

Regarding the piano in the FP3 and FP5, I called Roland and they claimed they sound exactly the same. I tend to probably believe them since it would be to their advantage to claim the the FP5 had improved the piano sound over the FP3.

The answer you received doesn't surprise me. The problem is that it could be the exact same sample, and it could still sound different due to different parts in each keyboard. The preamp could be different. Even the sampling rate or bit depth could be different.

I'm a big Roland fan. And under full-disclosure, I even do some work for them from time to time. But I wouldn't necessarily assume that these two patches sound identical. They may be based on the same sample, and thus are close enough to satisfy 99% of their customers. If that's true, then great -- buy the cheaper one!!! But again, I have no specific knowledgge or experience with these two keyboards. I'm just telling you my experience in the past (which may or may not apply here).

That has more to do with the controller's velocity curve and MIDI implementation than the module. I once tested a very expensive Yamaha Disklavier concert grand and found out that its maximum velocity output was 110 (instead of 127). That's a pretty huge limitation for such an expensive instrument!!!

I know what you mean. At least Yamaha is open enough to say that the P250 sound engine has more clarity than the P120 sound engine even though it uses the same samples, 22MB compressed for it's three layer Grand Piano 1 in both models.

And yes, the controller's velocity curve and MIDI implementation is the variable.