For powered systems like subwoofers and powered speakers, maximum continuous SPL output (measured using standards like CA20 ground plane measurements) should be a more important specification metric than power rating, since SPL better reflects real-world performance.

The 1% THD+N distortion threshold specified in the 2024 rule is a sensible and fair standard for solid-state electronics, and audioholics uses the same metric (along with 0.1% THD+N and full bandwidth sweeps) in their own amplifier power measurements.

A full power sine wave sweep for 5 minutes' duration is not realistically representative of how most amplifiers are actually used, since real program content does not run a single continuous tone for five minutes and only tests two channels of multi-channel amplifiers.

Audioholics has written a detailed, complex article on their homepage explaining the issues with the 2024 FTC rule, which they will link in the video description and supplementary materials.