Glossary
THD
Total Harmonic Distortion — the percentage of a reproduced audio signal that is unwanted harmonic content. Lower is better. Hi-Fi targets THD < 0.1%; cheap drivers run 1–5%.
When a driver receives a pure sine wave, an ideal speaker reproduces the same sine wave. A real speaker adds harmonics — distortion. THD quantifies that addition as a percentage of the signal.
What's audible
- < 0.1% — inaudible on transient material.
- 0.1–1% — audible only on tones, not music.
- 1–3% — adds warmth, often perceived as pleasant on tube-amp setups.
- > 5% — audible as harshness, especially at high SPL.
In the spec sheet
Manufacturers quote THD at 1 kHz at moderate SPL — the easy case. The honest number is across the frequency range and at near-max SPL. Quality reviews measure across the band.
Where this matters
Categories that use thd
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