Yamaha PSR Series PSRS950 61-Key Portable Keyboard Audio Styles: Audio Styles add recordings of professional drummers and percussionists from around the world. Yamaha's real-time, time stretch technology allows a wide range of tempo change without noticeable audio artifacts. Vocal Harmony 2: Instantly add three background singers with improved tracking, stability and realism. Powerful audio features: Use power audio features to cancel the center channel for quick and easy karaoke tracks. Setup repeat points within an audio file to let it loop, or change the tempo or pitch independently. Audio Link Multi-Pad: Trigger WAV files on USB flash drives from the Multi-Pads. Real Distortion effect: All-new guitar amplifier processing with effects.