I reported a while back I flipped a couple of M5s on top of each other and connected them in parallel. In my room, this sounded very good - better than the M100v4. I found the images created on some songs unnaturally large though so I experimented a little by moving them further apart and adding spacers (port plugs) between the cabinets. What do you know? They sound great! See link.https://drive.google.com/open?id=1-HTUof-ixrhav2AVhY0gi980WgAU2ZkR
I'm feeding them from an ADA-1500 and sitting 13 feet away. I can push them to 1350 peak Watts each...maybe more because I'm not sure I'm really capturing the peaks. This is at around +3 on my Onk. Even though the M5s are crossed at 80Hz to my 800v4, on bass-heavy songs the 1500/M5 combo gives in before my ears do on some well-recorded tunes. The songs that are shutting them down have some nice peaks in between some "quiescent" periods. These songs are "Drums of Thunderdome" by Estrella Boyer, the vintage version of St. Louis Blues by Wycliffe Gordon and a few others that are of similar acoustic signature. On Wycliffe Gordon, I can push each M5 to 1500W peak...LOL!
I'm surprised by how much power is really needed to get a visceral sense of well-recorded music. On these tunes, I could have used more power - a lot more. As I've said before, movies are a completely different story. I don't need an ADA and the Onk is just fine on BluRays at around -15.
Still, the ADA-1500 is a BEAST! Those M5s in parallel represent a load of around 3 Ohms which is a full Ohm below the rated load impedance of the 1500. That's 1300W to 1500W peak into 3 Ohms. That's 21 Amps of peak current into each pair of M5s!
If I replace the M5s with M100s, the ADA-1500 sources 2800W peak and the SPL is so high, I just can't take it even at 13 feet away.
I'm really looking forward to checking out the active M5s.