If you’re wondering why your car headlights flicker when you’re listening to music, the simple answer is power. Your amplifier is using a lot of it, and your car’s charging system can’t keep up.

If it only happens when your car is idling, and only with really loud bass, then installing a car audio capacitor or reinforcement cap may be enough. If it happens more often, or if you notice that your headlights dim even when the engine is "running," then you need to address the problem.

Your powerful new amplifier is hungry, and what it wants is electricity. The good news is that most cars produce more of it than they need, and this allows your car to keep its battery charged even when you have accessories like headlights, wipers, or your car stereo running.

The bad news is that your alternator isn’t an endless smorgasbord of juice. There comes a point where the rubber meets the road, and that point is often the installation of an amplifier, especially a powerful, dedicated subwoofer amplifier.