HearLoss - Hearing Loss Demonstrator
HearLoss is an interactive Windows PC program for demonstrating to normally hearing people the effects of hearing loss. With HearLoss you can replay speech, music and noise under a variety of loudness, filtering and masking conditions typical of hearing impairments. Best of all you can interactively change the settings and demonstrate their consequences.
The HearLoss program plays back pre-recorded audio samples of some speech, some music and some typical background noise, either singly or in combination. As it replays, three sliders control a simulation of the effects of three common consequences of hearing loss: loss in amplitude sensitivity, reduction in frequency range, and loss in spectral detail. Changes in the amplitude sensitivity slider changes the loudness of the sound, changes to the frequency range slider changes the upper frequency limit of the sound, while changes to the spectral detail slider changes the amount of fine structure present in the spectrum.
Download & Installation
The program is only available for Windows PCs by anonymous FTP from
Program only [0.5Mb]:
Full installation including sound samples - German translation [5Mb]:
Program only - German translation [0.5Mb]:
To download the full installation, right click on the link above and choose "Save Target As". Save the file to your desktop or to a folder on your computer. Then run the file to install the program and to add an entry to your Start Programs menu. Once installed you can delete the downloaded file.
The full installation comes with three short audio samples in these files:
You can replace these with audio samples of your own. To make the audio files compatible with HearLoss, ensure that the files are saved with the format: "PCM 44.1kHz 16-bit Mono". The Windows Sound Recorder application can convert WAV files between formats.
To download the program alone, right click on the second link above and choose "Save Target As". Save the file to a new folder on your computer. You will then need to provide your own sound files as described above and put them in the same folder as the program.
Suggestions for Use
This is one way you might use the program to demonstrate the effects of hearing loss to normally-hearing people:
The three audio files are loaded into memory and scaled so that they can not overload the output when added together. When replay starts, the combined audio is processed in the frequency domain to remove frequency components above some limit set by the frequency range slider, and to smear energy across frequency according to the setting of the frequency selectivity slider. The spectral smearing is based on the technique described by Baer & Moore (1993). Amplitude sensitivity is changed partly through the Windows audio mixer volume control and partly by scaling the signal.
The graphic equaliser display is based on a number of auditory filter sized channels, each 1 bark wide. The graphic equaliser has a simple damping mechanism to reduce fine temporal fluctuations.
Approximate parameter settings for the sliders areas follows:
The bark scale is a measure of auditory filter width. When the frequency selectivity control is set to one bark then sound components that fall within one bark of one another interfere and so cannot be easily distinguished as separate elements of the sound. By definition, normal hearing has a frequency selectivity of one bark, so the program does not need to do any additional frequency smearing for the normal setting.
This program may not run correctly on PCs with a low processor speed which are unable to perform the frequency analysis and synthesis in real time. A processor speed of 1GHz or greater is recommended.
Please send suggestions for improvements and reports of program faults to SFS@phon.ucl.ac.uk.
HearLoss is not public domain software, its intellectual property is owned by Mark Huckvale, University College London. However HearLoss may be used and
copied without charge as long as the program remains unmodified and continues to carry this copyright notice. Please contact the author for other licensing arrangements. HearLoss carries no warranty of any kind, you use it at your own risk.
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