Task: Convert a time domain function into a frequency domain function in C#

I'm looking for an experienced C# developer to convert my existing time domain code into frequency domain code. This project involves working primarily with audio signals. The primary purpose of this conversion is to enhance signal processing capabilities.

Essential Requirements:
- Proficiency in C# programming and MathNet.Numerics
- Experience with signal processing
- Familiarity with frequency domain transformations, particularly the Fourier Transform