Open your audio file. Adjust its volume first, because you need to deal with the midrange clipping distortion.
Adjust it to only about one fifth of the original, then select the part you want to deal with, open the equalizer in the action menu, select 30 segments of graphic equalization, pull all low frequency and high frequency, leaving only the intermediate frequency part.
Handle it several times. You have to listen to the specific role before you know whether it is satisfied (in the process, you should always pay attention to the waveform of the volume and do not exceed the border).

The second method. Destructive processing of audio and mixing it into super compressed audio data for destructive distortion can also achieve a similar effect, but the bottom noise is very large. This method is not recommended.
The third way is to use the ozone plug-in in the recording software. Ozone has the option of telephone and radio function for the audio processing part, but there are a lot. You have to try one by one to know which one is.
Article source: Jiangmen recording production http://www.sjttv.com