Absolute Threshold of Hearing

The simplest property to exploit is the ATH (Absolute Threshold of Hearing). We simply cannot hear sounds which are too weak. The ATH varies a lot with the frequency of the test sound, which can be seen in Fig. 2. The curve is approximated from experiments on a number of subjects (see [1]).

Figure 2: The absolute threshold of hearing. The numbers indicate the age of the test subjects.