There are a number of ways a person can be hard of hearing. Audiologists use an audiogram to chart the results of tests on a patient's hearing. Frequency ranges from the extremely low frequencies on the very left of the graph to the very high frequencies on the far right. Frequencies of 125 or 250 Hz are low tones like the bass notes on a piano. High frequencies of 8,000 Hz are high tones, like the treble notes on a piano.
Decibels describe the loudness of the sound.
Zero decibels is very soft while 110 dB is very loud. Normal speech is around 45 dB. The softest sounds that a person can hear 50 per cent of the time is considered their hearing threshold. These thresholds are measured and marked by an audiologist on the audiogram. Get into groups of four or five. Estimate how many Hz each would be.