Speed Accuracy
Speed accuracy states how closely average playback speed matches its nominal value.
It is usually expressed as a percentage deviation. A smaller permitted deviation means closer agreement under the stated conditions; this is separate from short-term wow and flutter.
Speed Accuracy — Turntable
For a turntable, the figure describes platter speed relative to the selected nominal rotation rate. A consistent speed error shifts musical pitch and playback duration.
Keep the tested speed and any upper-limit wording with the value. Do not treat a pitch-control range as an accuracy rating, and retain different stated results at different speeds rather than assuming they are identical.
Speed Accuracy — Reel-to-Reel
For a reel-to-reel deck, accuracy describes average tape transport speed relative to the selected nominal speed. An offset affects both pitch and the running time of a recording.
Compare the same speed and stated operating conditions, including any relevant reel or transport condition. A stable but incorrectly calibrated transport can have low wow and flutter while still having a steady speed error.