Here is the pair right out of the box:
Here they are after a 5 minute break-in @ 80Hz:
Here is factory claims:
Looks like both resonances are a bit lower in mine than advertised, but to be honest I think they both require a much more robust break-in before I can comment a whole lot further on the free air resonance differences. Look at them above 200Hz, they are almost identical. Since I plan on using these from ~350 and up, I am not sure I even give two shits about that difference.
If I get really inspired, I will run them on an extended break-in. I will say, though, at 80Hz these are not very clean drivers. I understand they have limited Xmax etc, and are essentially advertised as a midrange, so I will let it slide.
I remember seeing some off-axis measurements that DanN posted and if I recall correctly, the flat cone does offer some off-axis benefits so when I build what I will be building with these - I will be mating these to those big fucking Beston ribbons. (I am trying to browse the PE website - that piece of shit goes into R-Tard mode several times a day, anyone else notice that? I only visit a couple times a day, and it seems quite often it just refuses to load).
The comment about the PE main site holds true on my work computer as well as my mobile devices and my real computer at home. Sad. Then, a few minutes later it comes out of it. I wonder if Stahl is hosting it on a computer in his basement.
(with apologies to DanN for stealing his shit):
There is a small issue at 1500 that shows up off-axis, but it is a developing null not a bloom, so I will take it. It is still fairly directional to 2K, so throwing the Beston on top of it at 1500-1800 should work just fine.
Still deciding on a woofer. I have a lot of them around, but not sure if any of them fit the them here (over priced for what you get lol). Seriously though, probably the 8" Rival aluminum cone bad boy.
Sooooooo I am currently in the process of likely buying a home, which means I will be packing this project up and putting it into storage. The hope is buying a home is incentive to keep me home and doing projects instead of going to my favorite watering hole all the time. I will be keeping an eye on high end 8-10" drivers in the meantime as I believe the right woofer could anchor what very well could be a pretty world class monkey coffin. Maybe this one:https://www.parts-express.com/aurum-cantus-ac250-75c2c-10-woofer--296-454
Just kidding, although it would definitely fit with the "over priced for what you get" theme.
Anyways, for purposes of planning using this driver as a midrange, it appears to be more than OK. Dan's distortion measurement showed better than -60db above 200Hz, so effectively it is a non-issue as far as non-linear distortion goes. The Beston is an unknown, but that is ok. Ill leave the drivers out, maybe run an extended break-in tomorrow. Time for a beer.
I have a signature.