Hi all I have just acquired a pair of Acoustic Research AR18s speakers which sound a bit flat so opened them up to find the positive and negative wired incorrectly inside the speaker. With hope that this would change the lower end sound but unfortunately although better it wasn’t as good as expected! I am now wondering if the mid/bass speaker has been replaced with an inferior speaker although all the serial numbers look like they match original parts listing but I was led to believe that most of not all the speakers had the square magnet design whereas the ones installed in the speakers I have are round? If anyone could confirm this that would be great as if the case is that the speakers are incorrect then I will try to source the originals and replace them and give the speakers another go.