Two options that I know of to convert midi to wav with your choice of sounds are vst instruments (supported by cubase, for example), and soundfonts (don't remember which software I used).
So if you can find either a vst instrument or a soundfont that sounds like a PC speaker you can use those with a software that supports the format.
So if you can find either a vst instrument or a soundfont that sounds like a PC speaker you can use those with a software that supports the format.