Yeah the tweeter is aluminum. It may not be as refined as an audiophile grade tweeter, but I didn't notice any harshness. The 7004 treble did sound more refined than my tiny deftech ProCinema60s. There are a lot of deftech dealers around, shouldn't be hard to find. A little off topic, but I was surprised how much better the 7004 sounded than the new GoldenEar speakers which cost more I think (not bipole).
