8. Volunteers initial evaluation - Gazwilde/EQ-Software-For-Mixing-Audio GitHub Wiki

All participants on the day of testing answered positively to the questions, with none of them stating they felt tiered or fatigued and have not been in a loud environment. Two of the participants were practicing drummers, one a practice drummer/ guitarist. One, a practicing guitarist. The other volunteers play guitar but have not playing in a live situation for a number of years.

Testing took place at each participant’s studio. Completing the tests in the right listening environment proved important for accurate results. Choosing the quietest part of the studio helped eliminate any external noise that could affect clarity of the results from the test. Beyerdynamic DT770 headphones were used for the test. They are of closed back construction, which helps eliminate any external noise that could effect the outcome of the test. The headphones have a frequency response of 5 to 35,000Hz (Beyerdynamic 2018). Calibration of the software was completed by the author for each individual participant before each test. This procedure entailed setting the software volume to 1% (out of 100% 1% being the lowest volume 100% being the highest volume) and playing a pure tone, then lowering the volume of the soundcard to the point that the pure tone could just be heard, as recommended by the software developer (Free Hearing Test Software 2018). The reason for the calibration being conducted by the author and not the individual participants, ensured each test was standardized. This procedure involves playing a pure sound wave tones at different frequencies, set by the operator. The software then plays the tone first tone frequency starting at 1% volume, it then increases the volume, as soon as the volunteer hers the tone, they press a button. This action stops the tone, resets the volume to zero and the software then plays the next tone in the sequence. If no tone is detected by the volunteer, the volume reaches 100% the software will automatically go to the next tone in the sequence

• How tired and fatigued they feel?

• Have they been listening to any music?

• If so how loud?

• Have they been in a noisy environment?

Testing Each participant placed the headphones on, ensuring corresponding left and right headphone speakers were fitted correctly. The participant then completed the tests. A number of tests were carried out on each participant to ensure enough data was recorded. It became apparent that if the steps between each frequency were too broad, some hearing loss would not be detected. So tests with shorter steps between frequencies were taken. The down side to this is that the tests take a lot longer. A report by NCBI recommends that hearing test tones should range from 250 to 8000 Hz (NCBI 2004).