Pitch Shift: Use the Pitch Shift control to select how much Hear Birds Again lowers the frequencies of high-pitched sounds. Select 1/2 to divide them by two, or equivalently to lower them by a musical interval of one octave. Select 1/3 to divide them by three, or lower them an octave and a fifth. Select 1/4 to divide them by four, or lower them by two octaves.
Start Frequency (kHz): Use the Start Frequency control to select the frequency above which Hear Birds Again shifts sounds down in pitch. The frequency chosen should mirror your hearing curve as revealed by your audiogram. For example, if your high frequency hearing loss becomes moderate to severe at 3 kHz (see audiogram below), then use the 3 kHz setting.
Output Level: The Output Level sound meter verifies that the app is receiving and processing an input signal. If the level is fairly high (near the top of the green section), then all is well. If the level is on the low side (restricted to the lower half of the green section), consider boosting volume using the additional settings available on the “More Controls” page.
iOS Audio Volume: The iOS Audio Volume slider controls the output volume of your iOS device. It functions just like the up/down volume control buttons found on the side of your mobile device … if the volume is raised or lowered using one control, the change will be mirrored in the other.
Start/Stop Button: The Start/Stop button is self-explanatory. Hit “Start” to enable the app processing so that you can hear pitch-shifted bird songs. Hit “Stop” to disable the app processing.
Will Hear Birds Again Help You?
Our app is aimed at birders and other nature-lovers who have high frequency hearing loss and are unable to hear the high-pitched songs of many birds and insects, yet still have reasonably good hearing in the lower range, such that they can converse with other people without the need of hearing aids. Go here for more information.
If you do not have a recent audiogram that shows your hearing sensitivity at different frequencies (preferably up to 8000Hz), we strongly encourage you to obtain one. In the meantime, you can do a preliminary test yourself using the following online resources:
1. Go Here to test your hearing using a great online hearing test provided by the University of New South Wales in Australia. If done correctly, this will yield useful information about your hearing sensitivity from low to high (up to 16,000 Hz!).
2. You can also learn a lot about your hearing by visiting Hear For Yourself on our website, where we provide numerous examples of pitch-shifted bird songs, along with the original field recordings. If you suffer from high frequency loss and set your playback volume to a very low level, you are likely not to hear many (if not all) of the high singers, while the pitch-lowered versions should be clearly audible.
The Optimal User:
Our pitch-lowering approach to bringing back the birds requires that the user still have reasonably good hearing in both ears up to around 2000 Hz (2 kHz). The audiogram for such an “optimal” user might look something like this:
NOTE: For potential users who have audiograms, feel free to contact us and request that we take a look. We can generally tell at a glance whether or not you are a good candidate for our pitch-shifting approach.