I just acquired my new pair of M75 Scumback speakers this week and installed them into my closed back Mesa Boogie Stiletto Ace 2x12 combo. Let me tell you this: I have never been as impressed with a fresh-out-of-the-box speaker in my 29 years of playing guitar...and they're not even broken in yet! My amp is a Marshall-voiced circuit that runs 2 EL34s, 12ax7's, and is tube rectified. You know the recipe- flat out rock amp. I assume Boogie makes their speaker choices because they buy them by the megaton in bulk from Celestion, but the REAL tone of this amp is now coming to life with the Scumback M75's. Here's the deal- perfect representation of the Greenback sound and no upper-mid harsh spike that one can get with some Celestion models. Just that really nice 'grind' and 'crunch' when you hit that open E chord and hear the each note ring. For me, it's like Ace or Angus on a really good night in 1977. That's what I'm getting now. Can't wait till they're fully broken in. Man, I'm so happy with these speakers now and it's like I have a whole new amp! Nice, thick, raucous EL34 tone thanks to these Scumbacks. I finally have found my new favorite speaker! Next, I will have to make some YouTube clips as soon as I can make some time. If you're thinking about replacement speakers, I would recommend Scumbacks without reservation. Most of you current Scumback owners pushed me towards these speakers when I inquired several weeks back...and I thank you all for the recommendation! Cheers, Khan.