An auiogram is a standard way of representing a person's hearing loss. Most audiograms cover the limited range 100Hz to 8000Hz (8kHz) 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 dBHL. 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).