There are many space-age materials much lighter than steel, but significantly stronger and more durable. The only reason the 9000 pro was made from steel is that steel is less expensive than graphite/boron composite materials. Strength was probably the last thing on Yamaha's mind when they manufactured that keyboard. Just because a keyboard is heavy does not mean it's a high-quality board. There are much heavier boards out there that sound awful.

Donny is right when it comes to lugging this stuff from one job to another, day in and day out. Lighter is better. Those 36.5 pound Barbetta Sona 32C's sound fantastic, and they don't provide the sweat and back pains my 95-pound Peavey SP5G's produced. I'll take lightweight over heavy as long as I get the same quality sound.

Cheers,

Gary