Casio Casiotone, 61-Key Portable Keyboard (CT-S1BK) The Graphite reinforcement rods provide

The Graphite reinforcement rods provide massive sustain and excellent stability

If that doesn't solve the problem and further troubleshooting is needed

or angled back to act as a personal monitor

silk-dome transducers (tweeters) provide superior stereo imaging from nearly any listening angle

If you were to begin with a vintage rhythm pickup

Casio Casiotone, 61-Key Portable Keyboard (CT-S1BK) The Graphite reinforcement rods provideCasio Casiotone, 61 Key Portable Keyboard (CT S1BK) About this item 61 full size key with touch response Stereo Grand Piano plus 60 other AiX powered tones Powerful bass reflex stereo speaker system with surround effect Class compliant USB MIDI connects to free Chordana Play app Optional WU BT1 Bluetooth MIDI Audio Adaper. Optional 6xAA battery power (AC Adapter and music rest included) Casiotone CT S1BK Portable Keyboard In 1980, the original