You Can DIY! Designing a Powerful Speech Compressor
This project describes a dynamic compressor circuit working in reverse. Instead of limiting the maximum volume level of an audio signal, it leaves loud parts alone and instead raises the volume when it’s too soft. The project uses a famous VCA circuit designed by David Blackmer of dbx fame, developed in the 1960s, whose patent expired long ago. The resulting original design is useful for transcribing conference meetings, court reporting, or any other situation where the volume level of recorded speech can vary by a large amount.