I get the noise on the left in my LS2 (although not as bad as you do by your description) so the comment about head shape is interesting. Might try some padding when it shrinks down a bit because it should get worse when that happens if that is the cause.
Bike shops that won't let you try/test would really benefit from test lids or a wee wind tunnel considering the price of some helmets, and how different we all are. But I guess with the cost involved with either option...
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