Preferred listening levels for bands of speech in relation to hearing aid selection

The Most Comfortable Loudness Level (MCL) was measured for 24 normal-hearing subjects, using narrow bands of speech having centre frequencies of 0.25, 0.5, 1.2 and 4kHz. MCL's were equivalent for octave band and one-third octave band stimuli. The sensation levels (SL) for various frequencies closely matched the SL of the 60 phon equal loudness contour for pure tones. It was concluded, for levels around MCL, sounds which are equally comfortable are equally loud and that equal loudness contours for pure tones are also applicable to narrow bands of speech. Some implications for hearing aid selection are discussed. However, this investigation was primarily a preliminary to other studies more directly related to hearing aid selection issues.