nothing should surprise you :-), it's always nice to find out more than you knew before. test tones are the same sound just redirected through different channels, so if you have the gains adjusted properly you would ideally hear that same sound on each speaker (that is identical) directly in front of the speaker. however we all know that nothing is ideal, and a center channel in the same series is not identical to a main in that series, if it were it would be a main and not a center. lots of things impact sound, more than just specs and materials...