Quality speaker replacements? Do-able?

[sk-1]

This might be a really obvious question...

... but is it possible to replace the thin, tinny speakers in Yamaha and Casio keyboards with something of better quality and range?  Usually, the quality of sound from the line-out is a good indication as to the quality of the amplifier built in to the keyboard itself.  Wouldn't it make sense then, to have the built-in speaker replaced with something of much higher quality and fidelity, while remaining the same size?  This would be a great solution to improving the sound while keeping the unit portable.

I'm pretty sure that this must be possible.  What would be the best way to go about doing this?

[Gordonjcp]

No, it's not really possible.  There's a good reason why speakers that sound good tend to be bigger, heavier and more expensive than a cheapy speaker in a plastic box.

The built-in speakers in my Roland HS-60 (Juno 106 with speakers) are quite substantial and mounted in big heavy chipboard boxes.  They still don't sound *that* great.