I replaced my DGX 640’s bad speakers with PHILIPS 5.5 inch, 3 way car speakers. I never liked the DGX’s sound. They are dull and too mellow. Oh. man! Now, after replacing the onboard speakers, they sound crisp. I realized that Yamaha is not my parents. They need to earn profit, pay salaries. So, obviously, like all consumer products,m they are not well built. The speakers in those keyboards are not exceptions. They are cheaply made.