After hearing Notlos' wonderful demo, I decided to give the SD1 another try, so two days ago I went to the same store and played the keyboard for one hour. I will try to express my impressions in a cold way, hoping not to displease friendly people like Roel.
In my opinion the SD1 is a keyboard designed to impress; I don't know if Ketron engineers did that on purpose, but this keyboard has definitely a frequency response curve with a peak in the mid-range area. I didn't make any measurement (of course) but I like to fiddle with equalizers in my home studio and so, please, trust my word.
This mid-range emphasis has two effects: the first is that some instruments, like the trumpet and the acoustic guitars seem literally to "jump out" of the keyboard (remember the debate about the X1 "in your face" styles? Well, in the case of the SD1 we can rightly speak of "in your face" sounds). The second effect (at least in my case) is that this emphasis can lead to an earlier onset of the so called hearing fatigue and so I guess that if I owned an SD1 I would need a coffee break for every hour of playing, more or less. Don't get me wrong: some people could actually LOVE this kind of sound, but in my case the first time I played the SD1 (side by side with a VA76) I remember that every time I switched to the VA76 it was like breathing fresh air, because the sound was much more natural, but again I agree that this is an highly subjective issue. The same kind of midrange emphasis, on the other hand, makes that other sounds, like the acoustic piano, sound best in the mid-octaves: when I tried the piano multisample I noticed a decrease of sonic output from Bb4 to B4; I guess that this is due to the frequency response curve and, hopefully, not to an uneven multisample distribution, but still the piano doesn't sound so good in the top octaves.
One final word about the noise issue: I played a preset called "Pop organ" and heard a "sizzling" noise in the right channel; mind you, it's not the kind of noise that makes people turn around and say "What's going on?"; in a live situation you probably will never notice that, but in a studio situation (for recording purposes) it can be definitely annoying. I have tried to switch the effects off and the noise disappeared, so I guess that it was not due to the sample itself, but to the DSP instead and so hopefully Ketron will be able to fix this issue in the future.
Well, what can I say more? I am sure that the SD1 is not a keyboard that will leave people indifferent: some will love it, while others will never be able to accept its sonic quality and so in this case more than ever the advice is: "Try before you buy".
Friendly yours,
Andrea

[This message has been edited by Dreamer (edited 06-28-2001).]