I have a Ketron SD60 with built in studio quality speakers. They are only 20w but deliver more power than these). I have always found Yamaha speakers to be over-priced and below standard sound quality for over 30 years and these continue in the same sorry vein. I purchased M-Audio BX4 4.5" Studio Monitors 9 months ago and they are more powerful, have better clarity and bass kick these MS01's lack; and the M-Audio's do not have a sub woofer like these. If you have them as part of a bundle making them under £100, they will do 'a' job, but for under £100 you can get far better sounding and better quality speakers. Unfortunately, Yamaha are losing market shares to Korg and Ketron and instead of creating a better qualioty item to compete, they are using cheaper components (everyone agrees the keybeds of the Genos1 & 2 and other 'higher models are so poor, forcing many to purchase a master keyboard to run them through (I use a Fatar master on my G1)). They are also increasing prices to try and get the same profits from lower sales. An example is the CVP range. CVP-809PE to GP price difference was £2,000. The price now is an extra £5,000. When you consider the Kawai DG 30 is under £4,000 with a smaller body but the casing is just as nice as the yamaha. I have used Yamaha gear when gigging since 1992 but feel they are more interested in profit than quality these days.