Hi all, greetings from Australia. I am a first time poster & long time lurker. Could more knowledgeable members assist me in identifying 2 x Altec diaphragms. This 2 came out of my Altec 291-16a compression drivers during a routine cleaning of the magnet assembly. To my surprise both look different & sounded different in individual output. I included pics of the drivers, front & back. Thank you all.