There seem to be some confusion...SD1 keyboard is ketron, SG1 is SOLTON/Genesys.

Differences between SD1 & X1

1 - SD1: more power and more music for real musicians
2 - New semi-weighted keyboard design with 76 keys
3 - New sound generation with 48 Mbyte wavetable ROM
4 - 16 Mbyte of RAM Sounds for audio files (.wav, .mps, .ins)
5 - A more powerful Arranger for real band accompaniment
6 - New structure for the 6 Gbyte Hard Disk
7 - DSP and Vocalizer for attached microphone (XLR and Jack)
8 - Advanced MIDI file Player
9 - Built in "notebook" display for lyrics or text files
10 - Slick performance control with registration and performance memories
11 - New user interface for intuitive operation

Musically Yours UK