Sensation level expresses tone level relative to one individual’s own threshold

Evidence

Another reference level is the sensation level (SL), which defines the hearing threshold for a given individual. For example, if a person has a hearing threshold shift of +10 dB at a given frequency and is presented a pure tone with a level of 30 dB HL, the level of this tone can be expressed as 20 dB SL. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 2635

Categorization

• DEFINE: Distinguishes SL from HL/SPL reference frames, a foundational distinction for any applied audiometric work.
• corroborated: 2 independent passages support this claim — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 2635
• XREF: connects to: Auditory perception of the same physical sound varies between individuals