I set out yesterday to do a couple measurements then flip the MBMs over to see if the response was any different with the woofer closer to the ground. But I got sidetracked with tuning and Audyssey and other stuff.
Anyway, first up, here's the raw un-EQ'd response of both MBMs together with a 200Hz LPF. I've been running them bridged off one sub out from the receiver so I haven't bothered taking independent left/right measurements yet. All graphs are 1/24 octave resolution, no smoothing, 50 averages around the MLP.
And here's about as flat as I can get them using the iNuke DSP (couple tweaks from previous post):
Here's both full towers with subs. Manual graphic EQ on the 893's, iNuke DSP on the MBMs, no EQ on the subs (with a little bit of tweaking of the sub phase knobs which helped the dip at 70Hz a little):
After that I decided to see what Audyssey XT32 would do with it instead of switching up the orientation of the MBMs. One thing to note, if you plan on running MBMs off a sub out, you'll likely need to set a LPF via an amplifier prior to calibrating. I had just been using the internal crossover of the Denon with no LPF on the amp since I didn't see the need to stack crossovers. But obviously that's all off when calibrating, and I think it confused Audyssey when it heard such a wide range signal coming from the sub. Due to the efficiency of the Magnum 12 higher in the frequency spectrum, Audyssey probably measured the -3 dB point to be at like 100Hz. So I kept getting an ambient noise too high or signal too low error. After setting a LPF in the amp, everything worked fine.
It did a pretty nice job. After doing a couple tweaks in the iNuke software post calibration, here's the MBM + sub response:
And the whole system:
Sounds good too. It boosted the top end quite a bit compared to my manual tune. It's now pretty flat to 17KHz whereas before there was a somewhat gradual roll off starting around 6KHz. Low end is obviously much smoother.
Some gee whiz facts. Audyssey would generally set the levels of my old Jamo S606 towers to +2.5 dB. It set the 893's to -7.5 dB. The Jamos were rated at 89db/2.83V at 6 ohms, so I was expecting about 5dB difference in levels. 10dB certainly surprised me. So that's pretty cool. Also, it chose a 120Hz crossover for the 893s. Obviously not an issue since I'm crossing them at 200Hz to the MBMs, but would have been annoying if I was trying to cross them to a sub at 60-80Hz.