The sound restoration process deals with noise, crackles, scratches, clipping, hiss, hum and clicks removal, spectral repair, and advanced spectrogram restoration, and brings back some of the shine of the recording. If needed, warmth or harmonic enhancement will be done. The removal of the unwanted problems is done using RX Advanced Audio Restoration (Izotope), Sonnox Restoration suite, and Waves Restoration Bundle.
The next step is the harmonic enhancement of the material to get the best perception of the original sound. This is done through sophisticated hardware and software, and the result is quite spectacular. The harmonic enhancement is needed as the removal of noises, crackles, scratches, clicks, thumps does affect to a certain extent the audio part. EQ just doesn't do it in this case. Once the process is finished, the audio file is saved and prepared for delivery over internet, or memory sticks, or for burning on CD.