Pure Audio Project open baffle speakers

Doug:

I know its been quite a while since your last post to this string but here is my update to your suggestions. I tried the horn again and lowered the XO point to 400 Hz. Still was not that satisfied as there appears to be something missing at the very top end. Sold them (the PAP horns) and the new buyer confirmed the same observation. Many have added a "super tweeter" to the horn to fix this, but since that requires yet another XO point, I decided not to pursue this complexity as my current active XO is two way only. My in room pink noise measurements confirmed a drop off in frequency for the horns at about 10-11K Hz so this explains a lot. The Voxativ AC 1.5 reaches up to 15-16KHz in the same setup. The Voxativ is nice and flat with the main speaker chassis pointed straight ahead (as the off axis response is flat). They have a slight peak at 10KHz on axis, so I listen to them straight on (an not towed in as with the horns).
One additional advantage I have found with my active XO. I can tune the upper frequency response (to the Voxativ) by 0.5 dB increments and this really helps in tweaking certain recordings. I also built in an old school Yamaha (80's era) high frequency "tilt" control which tilts the HF response by variable degrees ( 1 through about 6 dB at 20KHz; hinged at 800 Hz). Don't really care for this much as the fixed shelving response works better for me.

One additional addendum. Looking to perhaps upgrade to the Voxativ PiFe. This is the driver similar to the AC 1.5, but with wood cones and phase plug. Cannot find any comparisons between these two drivers, except from Ines at Voxativ, who claims the wood makes the driver smoother and more detailed. Comes at quite a cost as these are about $5K a pair. 
It would be a plug and play replacement for the AC 1.5 as far as the XO goes, which makes life simple. Another suggested tweak is to replace the Al metal phase plugs in the 1.5 with a wood version from the upper end drivers, but I'll be d'mned if I cannot get a grip on those plugs to remove them.

I have heard the trios and the quintets.
IMO not a good speaker. Can be loud? yes. Are they heavy? yes, very.
Do they sound good? No. 
Very low definition. Can't play them at low volume.
I would not buy them. I would not take them if someone offered them to me for free.