To make audio recording sound like a phone call you will need to use an equalizer. You will have to set your EQ settings to the following:
- Reduce frequencies at 500Hz and below by 15dB
- Reduce frequencies at 6,000Hz and above by 15dB
- Boost frequencies from 600Hz to 5,000Hz by 2dB
You may cut more at 0Hz-500Hz and 6,000Hz-20,000Hz and boost at 600Hz-5,000Hz if you want a more significant phone call effect.
Also, some DAWs may offer EQ presets designed to make your voice sound like on a phone, you might as well try using it.
This method is designed to replicate how phone calls sound.
500Hz-5,000Hz frequency range gives the most presence to your voice. Phone devices focus on this range to give your voice clarity which creates a specific phone call sound that is clear, but at the same time a bit harsh and tiny.
Use your phone
A second method to create phone call audio is by actually using a phone. Calling your phone and recording the conversation into the microphone will give an authentic phone call voice impression.