The software divides the signal spectrum into 14 bands and applies the type of compression dynamics in each band that the older analog ReSound hearing aids apply in two bands. This allows a more accurate representation of the hearing loss, and the digital signal processing allows more tricks to be played with the signals. The top of the line BTE has two microphones connected to the signal processor through filter and delay circuits to allow exact matching of the characteristics of the microphones. The microphones are adjusted to match each other to within 0.25 dB at the factory. The microphones can be software set by the audiologist to cardioid, hypercardioid, bi-directional, or omnidirectional, depending on the user's preference.
Different programs can have different microphone settings.
For example, you might want to use bi-directional in the car, to hear front and back, but not to the sides, or cardioid in a restaurant where all the people you want to hear are in front of you. You change programs by pushing a button on the hearing aid. The Hearing and Speech Center gives unlimited free, reprogrammings of your hearing aids, for as long as you own the aids. So you can change your mind, if your needs change. The ReSound feedback control is set for your ears at programming time in your audiologist's office.