# audio_cleaner

Removes 60 Hz electrical hum (and harmonics) from WAV audio files
using a real FFT-based notch filter implemented in C.

## Requirements
macOS with Xcode Command Line Tools:
  xcode-select --install

## Build
  cc audio_cleaner.c -o audio_cleaner -lm

## Run
  ./audio_cleaner input.wav output.wav

## Input requirements
  - 16-bit mono PCM WAV, any sample rate

## Output
  - Filtered WAV at output path
  - "Done" printed to stdout

## How it works
  1. Read WAV → double[] samples
  2. Zero-pad to next power of 2
  3. FFT (Cooley-Tukey radix-2 DIT)
  4. Zero bins at 60/120/180/240/300 Hz ± 5 Hz
  5. IFFT → reconstruct time-domain signal
  6. Write output WAV