How do I connect my digital piano to my speakers?
Some smaller portables and digital pianos with onboard speakers don't have line outputs, so your only choice is the headphone jack. In this case, you need a cable that has the matching connector to your headphone jack with the mono 1/4-inch plug on the other end.
Do you need speakers for a digital piano?
If you're a beginner, you may not really need high-end tones and sounds at first. ... Speakers are also important to consider because they are the primary sound output of the digital piano. However, keep in mind the output will also depend on how you play. Just make sure that the speakers are of decent quality.