The light bulb serves as a damper to prevent overheating of the voice coil. At high volume, the bulb begins to light, thus adding resistance. If you remove it, you will hear a bit more dynamic range at high volume, but you risk damaging the speaker. When I was manager of the repair department at a shop in Dallas that sold Norman Labs, customers would bring in speakers with burned out light bulbs, probably related to Emerson, Lake, and Palmer or Led Zeppelin. The Norman Labs 10 used a long-throw woofer. This allowed very low and strong bass response, exactly what a college kid wants.