i got a power inverter in my car and it works great, no buzzing sound at all. only time you hear like a pop is when my system is on pretty loud and i turn the inverter off, but thats because i wired the inverter to another switch. for this carputer i might stick with this inverter or i might get an Opus Power Supply, just because you can wire it so that when you turn your car on, the carputer turns on, and when you turn your car off, the carputer turns off.