Sound activated light

So I was thinking that I need a tachometer on my system. Looking for a spl activated light. Perhaps first one comes on at 80db and another one at 5db steps. That way I would have a visual db meter and know if I have been too exuberant with the volume.
Download a spl meter to your phone, use that to mark the increment levels at your volume control when playing music. It will vary some, but get you close.