What is the difference between spl and hl

Roeser, M. Hosford-Dunn Eds. Audiology: Diagnosis. Detection is simply the ability to determine if a sound is present or absent, whereas discrimination is the ability to determine the difference between two stimuli or sounds. For example, during speech audiometry patients are asked to repeat spondee words e.

Sometimes, an SRT cannot be measured and the audiologist is simply interested in measuring the level dB HL where the patient is aware that speech is present speech awareness threshold , or SAT.

Another common measure used by audiologists is the word recognition score WRS. The WRS is a speech discrimination measure in which the patient repeats a list of 50 common, one syllable monosyllabic words. The minimum audible angle MAA is the smallest change in the location azimuth of two sound sources that can be perceived by a listener.

Figure 1. From: Gelfand, S. Hearing: An introduction to psychological and physiological acoustics. The following diagram shows the most commonly used graph developed by D.

Robinson and R. Dadson in Each line corresponds to a equal loudness contour. Loudness is a human perception and is not the same as sound pressure. Note that the same loudness requires different sound pressure depending on the frequency. The lowest equal-loudness contour represents the quietest audible tone and is also known as the absolute threshold of hearing. In audiology, many different suffixes are appended to the unit of the dB.

This micropascal reference was selected because it was the quietest sound pressure level that a group of normal hearing test subjects could detect. Hearing levels are measured with pure tones at different frequencies and the hearing level of an individual will vary depending on the frequency chosen. The notation of nHL is a reference to the frequency-specific threshold of normal hearing subjects.

Looking for help? Visit the Support Center for additional downloads. Download and run TeamViewer for technical live assistance. All quick guides.