Maximum SPL
Maximum SPL is the greatest sound pressure level a product is specified to produce under stated conditions.
The result depends on measurement distance, frequency range, duration and any distortion limit. Peak and sustained output should not be treated as interchangeable.
Maximum SPL — Loudspeaker
For a loudspeaker, maximum SPL describes output capability at the specified measurement position. A single-speaker result and a result for a pair or array have different conditions.
Compare ratings at the same distance and with comparable bandwidth and distortion criteria. A short peak figure does not establish sustained full-band output, and room reinforcement can change a measured result. Keep sensitivity, which describes output for a stated input, separate from maximum level.
Maximum SPL — Subwoofer
For a subwoofer, maximum SPL can vary substantially across the bass range. A figure at one frequency does not describe the output available at the lowest frequency the subwoofer can reproduce.
Compare frequency, distance, duration and distortion conditions together. A room-corner measurement is not directly equivalent to a free-field result, and peak output does not describe continuous operation. Use extension and output information together rather than assuming the deepest quoted response also occurs at maximum SPL.