For car audio enthusiasts, especially those interested in competing in SPL competitions, amplifier efficiency should be one of their primary concerns. In this first of three articles on efficiency, we take a close look at the Rockford Fosgate M5-1000X1 Class-D subwoofer amp and analyze how well it makes use of power at different output levels. […]

If you’ve been around the car audio scene for a few decades, then you’ll recall a time when almost all amplifiers doubled their output power when the load impedance was halved. For example, an amplifier might have been rated to produce 75 watts per channel into a 4-ohm load and 150 watts into a 2-ohm […]

Not long ago, we looked at how an increase in subwoofer voice coil temperature reduced the power delivered from your amplifier. With component temperatures easily exceeding the boiling point of water, the impedance of the voice coil can increase by more than 50%. Manufacturers that understand this go to great lengths to include technologies to […]

We can’t count the number of times we’ve heard people say that listening to music over Bluetooth A2DP doesn’t sound as good as if you played a WAV file directly from a USB memory stick. So we fired up the Sony XAV-AX7000 multimedia receiver that we reviewed in late 2020 and made a series of […]