I've noticed that my NHT SuperOnes subjectively sound better when i remove the grilles. Specifically, the off axis sound from the tweeter seems better. This is most noticeble if i'm sitting in between the speakers very close to the speaker wall (since the speaker drivers aren't pointing directly at me) The highs just sound clearer and brighter. Is this normal? Also, are speakers supposed to have the grilles on or is just for looks?