An audiogram is a standard way of representing a person's hearing loss http://www. phonak. co. uk/ccuk/consumer/hearing/audiogram. htm. Most audiograms cover the limited range 100 Hz to 8000 Hz (8 kHz) which is most important for clear understanding of speech, and they plot the threshold of hearing relative to a standardised curve that represents 'normal' hearing, in dB(HL). They are not the same as equal-loudness contours, which are a set of curves representing equal loudness at different levels, as well as at the threshold of hearing, in absolute terms measured in dB SPL (sound pressure level)...