i dont think the tone really matthers, if you want to know wheter your kit is 'tuned' right the drum must sound the same on every point at the edge of the skin.
im bored so ill draw you an example:

drumskin + sound:

___poink______
I I
poink: I I
I I pooonk <------this one needs tuning
I I
I____________I
poink


when they all sound POINK your skin is tuned.

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