@ Gustavo
you are right; the M50 and the SV1 have the same sound generation, the Korg EDS (Enhanced Definition Synthesis). The Kronos has 9 sound engine (for electric piano sounds it use the EP-1-MDS sound engine).
The SV1 can have a richer and warmer sound (using the Vox Valve Reactor technology) compared to M50. The Kronos (in my opinion) has the best electric piano sounds (through a new sound generation technology).
@ Elecpiano
that you say is the RX component of a sound in the SV1 engine.
Korg’s RX noise technology, RX being short for Real eXperience. RX noise is the mechanical noise created by some, but not all, instruments. In the case of a piano, for example, the mechanical noise would include the sound of the key being released, the hammer returning to its rest position, and the damper resonance of the strings. This all goes to make the instrument sound more authentic.
The RX noise level can be adjusted by pressing the Function button and then using the Bass control in the EQ section to adjust the level.
It's like a sound with two layer (the sound itself and the RX component). You can control the RX in real time building the sound you like (and store it in a memory location for future use).
Also
everyones Rhodes sounds different therefore everyones perception of what a rhodes should be is different. The RX level can adjust the SV1 rhodes sound to your tastes; the amp simulation and the effects allow you to find the sound you looking for too.
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but, in your opinion, why Clavia don't make new ep sounds? this is the question in this topic...
is it a hardware limitation? (in the management of samples that need many layers to be expressive and real. nobody knows how many layers can manage the Nord Piano Library.)
only marketing choice? (with new Nord Piano 3, it makes sense to have a set of acoustic piano that covering every musical genre)