The Yamaha CS1x is a sample-based synthesizer released by the Yamaha Corporation in 1996. Aimed primarily at dance musicians, the CS1x features analogue synthesizer-style rotary controllers and monotimbral synth voices.^[1]
The CS1x was succeeded in 1999 by the CS2x synthesizer.

The CS1x uses the Yamaha Sample and Synthesis technology, as well as General MIDI and XG voices from the MU-50 module.^[1]

The CS1x employs various arpeggiator presets and effects such as reverb, chorus (including flanging and celeste) and "variation" (a combination of reverbs, delays, modulation effects and equalisation).^[1]

The Yamaha CS1x can be expanded with a small sequencer workstation module. The CS1x, CS2x and AN1x synthesizers all have a small lip on the right hand end of the front panel to accommodate a QY or SU sized module.