Marty is correct. My experience with ATC is they are quite flat but have rolled off treble above 12K. So actually their soft dome tweeters are polite compared to other metal dome tweeters that extend higher.
The main thing with ATC is that the mid range has no dip or scoop. This means distortion and compression in modern pop rock can sound harsh on an ATC compared to the usual scooped midrange of the vast majority of speakers (B&W is prototypical). This translates to a more forward sound (close to the stage) than most smiley EQ speakers with a scoop.
Perhaps this is what Dave means by bright. I think Dave has the ATC 40 which is mid range in ATC domestic range. The larger ATCs actually have even more massive drivers - the 3 inch mid range “super” model is heavy (20 lbs).
The main thing with ATC is that the mid range has no dip or scoop. This means distortion and compression in modern pop rock can sound harsh on an ATC compared to the usual scooped midrange of the vast majority of speakers (B&W is prototypical). This translates to a more forward sound (close to the stage) than most smiley EQ speakers with a scoop.
Perhaps this is what Dave means by bright. I think Dave has the ATC 40 which is mid range in ATC domestic range. The larger ATCs actually have even more massive drivers - the 3 inch mid range “super” model is heavy (20 lbs).