When I set my output to sub-woofer the shaker constantly made some strange noises, no idea why? Impedance issues maybe. But as headphones it seems fine.
Also found that the vibes faded out as a bike revved up and i'd like to feel them throughout, so I whacked up the treble. I can now hear sound from the shaker but I can just about feel the bike at higher revs, think the cushion on my chair is soaking this up a bit unfortunately. Maybe another shaker attached to my handle bars might work, hmmm...