pianoman0018 wrote:witch one of these keyboards has the best sounds overall (im interested about sound quality not anything else)
motif es, motif xs, motif xf,yamaha mox, yamaha mx, yamaha s90 xs
Are you asking about sounds or sound quality? I can tell you about the basic sounds (the "voices" as Yamaha calls them)... The Motif ES is the only one there with the pre-XS sound set. All the rest are very similar to each other, they are all based on the XS sound set. Motif XS directly replaced the ES (I'm not sure how many ES sounds are in the XS as well). Motif XF has all the same sounds as the Motif XS, plus a bunch more. MOX has exactly the same sounds as the stock XS, though the XS can also take a number optional extra downloadable sounds that are not available for the MOX. S90XS has exactly the same sounds as the MOX except that it also has an additional high quality piano sound. The MX isn't shipping yet... it has XS sounds, but it it as yet unclear as to whether it has all of them, or simply most of them. It has "over 1000," the full set would be 1217 (" 1,024 Normal Voices + 64 Drum Kits, GM: 128 Normal Voices + 1 Drum Kit")
Yamaha boards also contain "performances" which are combinations of the underlying voices, and those differ among the models... they need to because of other differences, like some boards are capable of more simultaneous voices or more simultaneous effects than others, for example. There are other differences of course... like the feel of the keyboard, whether the keys have aftertouch, what auxiliary controls are available (sliders, pedals, ribbon, etc.), total polyphony, screen... really, a whole lot of other things, apart from the sounds themselves.
In terms of the other thing you said, sound
quality, I don't know. I've read where some people feel that the same voice sounds better when played on, for example, an XF rather than a MOX... people have talked about the possibility of higher quality electronics, i.e. better quality DACs, etc., but I don't know about that for a fact.
One thing about the old Motif ES, though, is that it could take PLG expansion cards, which gave it some other sonic capabilities (virtual analog, acoustic instrument modeling, etc.) and those expansion cards are not compatible with the subsequent XS+ series.