When playing hard rock or heavy metal music. You play a lot of 5th chords. Have you ever wondered how bands and guitarists like Slayer, Pantera, and Zach Wylde get that really low sound with their power chords? They drop the tuning of their low E string and tune it to a D. Go ahead and drop the tuning of your low E string to a D, crank up the distortion, and play an E5th chord and hear that nice low growl that accompanies that chord.
Heavier gauge strings can make a difference too. If you’re playing on 9 gauge strings, try going to a 10 or an 11 gauge. The difference isn’t a great deal and it may be a bit uncomfortable, but if you can adapt and make it work, it can help getting that low end growl just a little bit more.
Crank up the bass on your amp too.
That’s a simple thing that can make a notable difference.