I am trying to use the speakers on my midi keyboard as the default output device for Windows 7.

[BigBear]

I am trying to use the speakers on my midi keyboard as the default output device for Windows 7. I have a Casio CTK-3000 midi keyboard and want all sound to come out of the two speakers on the keyboard.

[ecookman]

I couldn't find much, but I hope this helps:
It appears that there is a AUX jack of some sort that allows you to do just this. You would just need a male/male 3.5mm audio cable to go from the audio output from you computer to the input on the keyboard. If you have separate sound software there *should* be an option to choose default output devices [with the IDT HD audio panel I can at least]. I am not certain if you can change the default audio device via win 7, my computer automatically detects if anything is attached and then switches to that for all sound so Ive never had to look.....

If you have the keyboard connected to your computer through a MIDI interface and trying to playback on the keyboard, I believe that this can not be done, my friend and I have tried in the past when his speakers blew.... and couldn't find a way to do just that.

I wasn't quite sure on what you are having difficulties with but I hope that helps.