Watch "The Ultimate Test: 440 Hz vs 432 Hz" on YouTube
The Ultimate Test: 440 Hz vs 432 Hz
Here, the two different tunings, 440 vs 432, are compared. Listen carefully; one of the two is much more "rich" in harmonics. Perhaps our ears simply perceive it better?? (I don't know) The fact remains that if you have a trained ear, you cannot help but notice the difference.