Do amplifier manufacturers always rate power output at 0.1% THD or lower?

The assertion that manufacturers should rate power output at 0.1% Total Harmonic Distortion (THD) or lower is rooted in the idea that such a standard provides a clearer and more realistic representation of an amplifier's performance. This level of distortion is generally considered to deliver audio quality that is closer to what listeners desire, ensuring clarity and fidelity in sound reproduction. By providing power ratings at such low distortion levels, manufacturers can offer consumers a better benchmark to compare the true efficiency and quality of an amplifier.

Many manufacturers do not adhere to this practice across the board, often providing ratings at higher levels of distortion. This could result in consumers misjudging the audio fidelity or power delivery capabilities of less expensive models or even some mid-range products. Ideally, power output should be communicated under conditions that reflect real-world usage, which typically involves using lower THD percentages for accurate assessment. Therefore, while it is not mandatory for manufacturers to do so, the expectation is that they recognize the importance of such ratings for informed consumer choices.