I think it's about adjusting yr ears, yr sensibility, about adjustment. After listening to a Nakamura or Sachiko M no-input album all the way through (even more the case with Sachiko, whose sine tones tend to be 'purer', more protracted, more intense), the sound of yr own ears, the ringing of everyday life, comes thru in some different sheen, some eerie aural afterglow. It's 'machine-like' and 'inhuman' to some - it challenges easy reliance on cliches about 'self-expression' and 'emotion' in music, pushes boundaries, gives an experience, leaves one touched by something that slips just out of grasp.
This is one of the only things I haven't been able to listen to all the way through. It's interesting, I guess, but it's very hard to listen to. Kind of painful, at least "Dance Music" is. It sounds a lot like the high frequencies from an CRT TV.