I had noticed this aggressive bass sound in many styles when played thru the onboard KB speakers but not so much on stage thru my PA systems..Then I read this post on the PSR Tutorial S950 forum..

"I have had around seven different Yamaha keyboards over the past twenty years and loved them all except this one. A great keyboard for gigging, and for anyone who is happy to have their eardrums bashed with the Bass. I have managed to reduce the noise a bit it it is far too thumpy for my tastes. I had thought about selling and going back to the 710 which was my over all favourite, but I would lose quite a lot of money and I would want a new one but they are no longer available. Eileen F"

Anyone else experiencing this with their S950?