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This I'm leaning toward standardizing at 0 dB.

Good for you, I guess, but the industry does not use this except when mastering to CD where -0.1 dB is the goal. As Matt already posted:

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Right or wrong, I don’t ramp my songs up to 0 or in other words no headroom. I was taught that it is the same idea as giving a final mix to a mastering engineer; they need a bit of room to work

Although there is no hard industry standard, no one I know wants to see tracks submitted that exceed -3 dB, I include myself.

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