The bass should not overpower the guitars, thats not its purpose. But it should still be heard. Iron Maiden is a good example of what the level if bass should be, you can definetly hear it.. but it dosent over power the guitars, it just adds much needed low end because maiden uses strats. But as guitars start to tune lower it will be much harder for the bass to be heard.. thats why you do what Cryptopsy and Cannibal Corpse do.

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