I picked these up for $120/pr at Partsexpress with free shipping. They're very nice looking drivers, and the weight and feel of the mid is solid. I especially like the protective mesh grille and thick aluminum mounting flange.
What I didn't like however was the somewhat ordinary looking motor. Sorry folks, no copper rings or sleeves in this motor, unlike their larger cone mid/bass and tweeters. I would have also liked to see a larger, more solidly constructed rear chamber instead of the plastic used in the back. The wool/felt padding stuffed into the rear chamber was a nice addition however.
A quick semi-anechoic frequency response plot. Notice the dip centered at around 3.8khz.
And here's the distortion plot from 300hz to 6khz. This is at 2w or roughly 96db spl. Very loud, painful listening levels.
This unit is pretty good distortion wise, except for between 1khz and 2khz. This is pretty obvious if you've read the tutorial in the diy article forum. Third order distortion (blue line) is considered fairly offensive, and 1-2khz is the range of human hearing that is especially sensitive to small levels of distortion. I would consider nearly 2% third order distortion between 1-2khz to be pretty poor performance. You could also notice that the third harmonic of 1khz-2khz corresponds to the dip shown in the frequency response plot. Coincidence?
From 2khz and up however, this driver is exceptionally clean. Below 600hz is only average, but I wouldn't use this dome mid below that in any case. Not only does second order (green line) distortion increase, but the rear chamber is simply too small and made of plastic... which leads to an audible resonance and a sort of "echo" effect that muddies up the sound. I'd keep this driver highpassed at 600-800hz.
So how did it sound? Using the Usher demo discs I listened to several vocal and guitar tracks. When highpassed at 650hz second order (12db), this mid sounded great. Very smooth, natural, and open sounding. Detail is definitely up there with some of the best cone mids I've heard like Scan -Speaks Revelator or Seas Lotus reference/Excel. It's also a bit laid back in the upper frequencies, but that was fine with me as I noticed some tracks that usually (and should) sound peaky or forward were more listenable. I was surprised that the distortion between 1-2khz wasn't really that big of a deal. Perhaps the fact that there's a -5db dip centered around 3.8khz helps to mellow out the sound.
Sensitivity is also better than your average cone mid. I recorded close to 93dbwm. Dynamics don't seem to be a problem either, and is actually quite good provided you are highpassing the driver above 650hz.
I'd say for $120 these are a pretty good buy. I like the sound very much, and wouldn't hesitate to say that from 650hz-6khz that this is one of the best drivers I've heard. You can expect a sound that's overall light and open, natural and uncolored, but a bit on the mellow side.