restoring audio from gramophone records
Equalizer is an application designed to assist when capturing and restoring audio from gramophone records. The most common situation is that the record is a normal stereo 33 rpm (vinyl) record, and that it has been captured via an amplifier/preamplifier which performs RIAA equalization electronically. In this case, Equalizer is not required, nor even useful.
There are, however, many situations where the equipment used for audio capture does not match the equalization required for the original record. The ideal solution is to buy a special-purpose pre-amplifier. Another is to capture the record to an audio file using the equipment at hand, then substitute the inappropriate equalization with the correct equalization as a digital process. That is what the Equalizer application is designed to do.