My initial goalI with this setup was to get it working nicely on a totally passive XO, and if you think about it, this is an incredibly powerful and efficient speaker system that could be run off any receiver or 100 watt amp and hit well over 110db or more. It's a very modular setup and very easy to set up and take down.
Next step was to make it fully active, which I did today. By going active I hoped to time align the horns, play with various XO slopes and flatten the frequency response.
I'm using an OpenDRC DA8 from miniDSP
If you're interested in this unit it's really nice for the $355 price, the only catch is it only has a digital coax input, which I was able to use an optical output on my Mac headphone jack and I used a simple converter to go from optical to coax.
An Adcom GFA-555II runs the 4 PA460, and a 4 channel Adcom GFA-2535 running each pair of horns.
XO slopes I've been playing with but are currently 48db between the high and midbass horns and 24db between the subs and midbasss. I ended up with 3-4 filters on each channel, quite minimal considering the flat response.
I ended up with 1.7ms of delay on the high freq horns, switching it on and off in hard pressed to hear a big difference, but it is slightly noticeable. I've played with time alignment a number of times and I'm led to believe a lot of people make a bigger deal of its importance than is reality.
All measurements are nearfield at one meter centered on the Seos24
Basic setup in minidsp
The PEQ filters on the high freq horn
Individual driver response and combined
Comparison to the passive setup, (disclaimer,I could have spent more time on the passive setup to improve the response no doubt), also note a subsonic filter at 30hz
Distortion is very low, less than 1% above 100 at 100db, less than 9% down to 20hz
Overall this configuration does sound better, it's more coherent and the flat freq response sounds better. Bass measures quite hot nearfield but is only about 3db hot in the listening position, plus I like bass .
If I haven't said this already, listening to powerful and dynamic music on these is a totally immersive experience, I find myself pausing the music to catch my breath at times, heart racing. They easily produce full spectrum response at 115db including bass, the entire house shakes and the walls rattle from the inside. Despite this the dual opposed configuration is vibration free, the horns never move a nanometer. I haven't stressed or maxed out the subs yet, with only "6mm" xmax these $95 subwoofers astound, with this much cone area bass is accurate and effortless. I really wish you could all come over and hear these =)