You’ve upgraded your car with new speakers, added a powerful amplifier, and maybe even picked out a subwoofer that could shake the mirrors loose. But wait—why does the sound still feel a bit... off? It’s not as clean or balanced as you expected. Welcome to one of the most overlooked dilemmas in car audio: integrating a factory head unit with aftermarket components. It might surprise you, but the key to unlocking crisp, balanced sound often lies in one device—the 4-channel line output converter. And if you're trying to power your audio upgrades without overwhelming your battery or causing voltage drops, there's another unsung hero: the remote battery terminal. Together, they form the backbone of any successful multi-channel audio setup