It's quite evident for me since there's no perfect tweeter.
I've done experiments with different tweeters from different speakers(yes, driving only tweeters with my almost perfect musical hearing as a former musician) and lemme tell ya that every tweeter is dirty as hell and needs correction one way or another.
In terms of wave propagation to the listening position tweeter bellow the woofer DOES make sence since it compresses the tweeter's imperfections and makes on the cetrain distance a clear and nice natural sound believe it or not.
I've done experiments with different tweeters from different speakers(yes, driving only tweeters with my almost perfect musical hearing as a former musician) and lemme tell ya that every tweeter is dirty as hell and needs correction one way or another.
In terms of wave propagation to the listening position tweeter bellow the woofer DOES make sence since it compresses the tweeter's imperfections and makes on the cetrain distance a clear and nice natural sound believe it or not.