Rob Scallon, musician and Youtube personality, just released this video where he plays the same riff over and over again but everytime down-tuning one step further. The goal here is to see whether or not playing in lower tuning affects the “heaviness” of your song.
Spoiler alert!: it does not.
In the end, those who are down-tuning to sound heavier are only being silly. However, playing in super low tunings, like 8- or 9- string guitar tunings (and even lower!) can get you an interesting sound, which is definitely different than “normal” 6-string guitar tunings.
Don’t tune down your guitar to be heavier; tune it down for aesthetics – the tone it gives.