440 Hz and 432 Hz are frequencies of musical notes. One frequency can be tuned to another frequency (444 Hz to 600 Hz, 528 Hz to 900 Hz, etcetc) according to choice of taste in sound and style. 440 Hz is the current standard tuning frequency across the world. 432 Hz tends to sound a little bit deeper and very slightly more melancholic compared to 440 Hz if you have an ear for detail.