Attempt to include actual tone through elastic bands that can be tuned. There could be different settings, in which the cords would be automatically tuned differently (scales, triads..) to show different proportions/scales of information.
This is just an idea of moving the slider by pulling (in this case) a ring.
Another slider with analog sound by building it over a glockenspiel. The pellet, which slides over the plates of the glockenspiel, is connected to the slider through a spring. That way, the sound isn’t muffled by it.