pawsman I looked at the photos and I believe the tweeters are the same as those in the IMs that I had. You can look inside through the port with a flashlight and see the maker and number of the tweeters and I'll bet they are as kdude66 suggests, the SB tweeters. It is also interesting that you are really happy with your IMs and it just goes to show how the electronics and room, probably more the room, can influence the sound, to say nothing of the actual ears and brain doing the listening. Audio is fun. Music is great. My desert island disk is Jascha Heifetz playing Bruch and Vieuxtemps, recorded back in the early 60's. I've listened to hundreds of hours of live violin, so that is the sound I go after with my system.