Today I received my personal shipment of some of the new MCM Select drivers. I purchased the 55-5670 8", 55-5665 6.5", 55-5655 4", and the 53-5165 1" tweeter. As JR has already done quite a bit of testing on the tweeter, I will simply refer to his evaluation. I will post my specs on those as well.
First let me say the build quality is outstanding. Plenty of cooling around the voice coil, through the magnet (save the 4"), under the spider. The tensile leads are well secured to the spider (however not woven into it). The cast frame looks to be well developed. I didn't notice any real issues with the casting at all. There is a nice gasket for mounting and the drivers have a simple, plain jain look and that is fine with me.
The specs track extremely well unit to unit and to the posted specs. I have done a little prelim modeling on them and once again, I am impressed so far. The 8s will do very well in just over 1 cube ported with an f3 in the upper 30s. The 6.5s look very good 20L with an f3 around 40.
The 4" (and I suspect its brothers the 3" and 5" based on their specs) is really a dedicated midrange/midbass driver. The specs are kind of odd in that they don't model well at all ported or sealed. But since these aren't going to be asked to play bass anyway, big deal! Give it a sealed chamber or even OB and let it play!
Here's the specs I took. Gentle massage of the suspension about 20 times in each direction. Vas was calculated using added mass. I am only posting for one of each driver but as I said they match each other very well.
Spec 55-5670 8" 55-5665 6.5" 55-5655 4"
Re 6.465 6.34 6.22
Fs 31.63 45.09 70.66
Le 0.88 0.923 0.477
Qes 0.4 0.519 1.193
Qms 1.253 1.655 3.025
Qts 0.303 0.39 0.866
Mms 24.31 14.41 3.559
Vas 59.86 17.85 11.16
SPL 89.14 87.37 87.32
I will post the DATS screen shots next.
Comments
I will echo Chucks commentary on their build quality and appearance - they have a classic, old timey look to them, very reminiscent of 70's and 80's stuff. This is a good thing.
Peering through the frame, there is significant voice coil winding visible, which leads me to believe the stated Xmax figure of 7.5mm is no lie.
I believe a pair of the 8" in parallel in a sealed, boosted alignment would make for a very nice powered subwoofer in addition to being a great candidate to anchor a traditional mid-sized tower.
I'm really thinking of using the 8s, 4, and tweet in a 70/80s type bookshelf, about 1 cube.