Removing high-frequency energy from a target impairs intelligibility up to 37 dB of attenuation

Evidence

SRTs increased linearly with a slope of 0.48 dB SRT/dB attenuation, but unlike the HP case, SRTs kept increasing until a floor value of 37-dB attenuation. Intelligibility remained at a SRT of about 10 dB for further attenuations. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3556