AC40 Support
Welcome to the product training for AC40 audiometer. On this page you will find an overview of all the available training materials and support.
Available Training
Pediatric Noise
What is pediatric noise?
Pediatric noise is a special noise stimuli that can be used as an alternative for pure tones, warble tones and narrow band noise. The use of pediatric noise is useful during sound field testing and visual reinforcement audiometry (VRA) as it helps to avoid standing waves as well as maintain the child’s interest during testing. In additional it is useful in other assessments, which requires narrow band noise such as pitch matching and minimum masking level.
Pediatric noise addresses two problems related to the use of narrow band noise.
1. Pediatric noise is calibrated in dB HL
In comparison, the narrow band noise is calibrated for effective masking of tonal sounds of the same dial setting. Practically speaking it means that the narrow band noise is a few dB louder than what is required for threshold measurements.
2. The shape of pediatric noise makes it frequency specific
While the plateau of the pediatric noise and narrow band noise are of the same width, the pediatric noise has very steep slopes, 100dB/octave vs. 12dB/octave respectively. In case of sloping hearing losses, the use of pediatric noise will not result in off-frequency listening.
Below graph illustrates the shape of the pediatric noise at 1000Hz.
Required equipment
- Headphones, insert phones or free field setup (FF)
- AC40
How to select pediatric noise
Ped noise can be run ad stand-alone on the audiometer or via Diagnostic Suite.
- On the standalone device, press Tests and use the wheel to select PED: pediatric noise.
When in the PED test screen, the channel 1 Warble button will flash slowly, to indicate that the stimulus used is the pediatric noise. While using this protocol, the audiometer allows toggling from pediatric noise to tone, warble tone and back to pediatric noise.
Note: If operated through Diagnostic Suite, pediatric noise (PED) will be available from the main tone screen in the selection of input.
- Conduct threshold evaluation using the pediatric noise for the desired audiometric evaluation method.
