Comparison
Casio PX-S3100 vs Yamaha DGX-670
Both combine piano playing with accompaniment, but their practical differences are substantial. The Casio is shallower and lighter, has dedicated line outputs and can run on batteries. The Yamaha provides a 16-track MIDI recorder and USB computer audio; the Casio has a three-track MIDI recorder and records audio to a USB drive instead. Decide whether frequent carrying or a more elaborate home recording arrangement matters more. Both require time to learn their accompaniment controls. Published and owner impressions differ on touch and speakers, so compare a familiar song, a saved setup and a quiet headphone session. Neither sound count nor amplifier wattage establishes the better instrument.
Open this pair in the interactive comparison
| Feature | PX-S3100 | DGX-670 |
|---|---|---|
| Price reference | USD 999.99 observed price (checked 2026-10-29). Confirm current price and availability. Instrument only; finish, tax, accessories, delivery and assembly may affect the total. | USD 849.99 observed price (checked 2026-10-28). Confirm current price and availability. Instrument only; finish, tax, accessories, delivery and assembly may affect the total. |
| Best-fit buyer | Players carrying a piano between home, rehearsals and small performances; Songwriters who want accompaniment, layered sounds and sound shaping in one instrument; Buyers who want a slim Casio with more direct control than the PX-S1100 | Home players who want to arrange and record songs without starting with a computer; Pianists who enjoy accompaniment and a broad sound selection; Buyers who prefer a readable display for settings and practice |
| Keyboard action | Smart Scaled Hammer Action Keyboard | GHS (Graded Hammer Standard) |
| Key construction | Not verified | Not verified |
| Key surface | Simulated ebony and ivory textures | Matte black keytops |
| Escapement / let-off | Not verified | Not verified |
| Maximum polyphony | 192 | 256 |
| Piano sound technology | Multi-Dimensional Morphing AiR | Yamaha CFX with Virtual Resonance Modeling |
| Speakers | 16 x 8 cm oval x 2 | 12 cm x 2 + 5 cm x 2 |
| Amplification | 8 W x 2 | 6 W x 2 |
| Pedals | SP-3 supplied; SP-34 optional; separate expression/assignable pedal input | Footswitch supplied; optional FC3A and LP-1 pedal unit |
| Bluetooth audio | Via included WU-BT10 adapter | Yes |
| Bluetooth MIDI | Via included WU-BT10 adapter | Not verified |
| USB audio interface | No | Yes |
| USB MIDI | Yes | Yes |
| Line outputs | Yes | No |
| Headphones | Two 3.5 mm stereo sockets | One 6.35 mm stereo jack; shared external-audio output |
| Dimensions (mm) | 1322 W x 232 D x 102 H; music rest detached | 1397 W x 445 D x 151 H |
| Weight (kg) | 11.4 | 21.4 |
| Apps | Casio Music Space | Chord Tracker |
| Warranty | Not verified | U.S. limited three-year digital-piano warranty; terms apply |