As promised... here are some quick prototype pictures of our new driver. This was one of the prototypes that had a carbon fiber cone. We nixed this particular design choice due to FR problems (large dip centered on 1.2K) and the production model uses a treated paper cone. On my standard test box (PE 0.75ft^3 cabinet) it has one of the smoothest response curves I've ever measured. It beats out even the Seas CA18RNX that held that position formerly for smoothest frequency response from 200Hz-3.5K.
The motor design is pretty cool. Of course its XBL^2 for a large flat BL curve. This motor has about the same BL curve as the Extremis. The voice coil is a large 1.5" unit for killer power handling. The combination of perimeter cooling holes along with the phase plug (no dustcap) not only allows good venting, the design forces a steady flow of air through the gap across the former/voicecoil. Since about 90% of voicecoil cooling is via convective heat transfer we get absolutely superior power handling and significantly lower power compression with this type of design. No chuffing or noise problems at all, even during full free-air excursion this design is very very quiet.
I like this basket design. It comes with the foam backing so you don't have to fiddle with methods of sealing the cabinet. Notice the screw holes for mounting are off-set enough that the gasket gives a nice 360 degree seal without having to monkey around with gasket material. The venting around the perimeter is great with a nice open design for dipole use. The front of the basket has a nice profile that looks really slick. About the only basket design I like better (and only in some ways) is the Seas cast baskets.
Here it is next to the Parts Express RS-180. The RS-180 looks a lot bigger and it is... the motor and shielding cup make it look like a larger driver. The only thing larger though is the rear. The cone diameter is the same. We smoke the RS-180 in every measureable parameter (FR, distortion measurements, usable output, power compression/handling, etc, etc...). Of course we should, our cost on the EX-6.5 in volume is more expensive than the retail price of the RS-180! Performance wise we should offer almost twice the usable output of the RS-180 down low so the value proposition falls a little better into balance if you analyze the entire solution.
I know a lot of people are in love with the RS-180 due to the price/performance. If it didn't have the poor FR issues of the aluminum cone I'd agree. The poorly behaved cone causes you to have to use steep filters down low. This translates to an expensive crossover & tweeter needed. The crossover components alone can double the price of the solution and it no longer looks like such a great value when you factor in the total system cost. The EX-6.5 in contrast, works wonderfully with a 2nd order electrical solution crossed over at a more reasonable 2.5Khz. All of my designs with the RS-180 have been forced to either use a notch filter or crossover steep down around 1.5K.
Here is the EX-6.5 next to the Extremis. Size wise these look like a better match. The T/S parameters of the EX-6.5 are much closer to the RS-180 (which was our target) with a more traditional 88-89db sensitivity. Notice we use the gold plated push terminals which add a little cost but make for easy connection chores. The EX-6.5 also has about 5/16" less mounting depth. This allows it to fit in a 2x4 stud space (hint hint... in-wall designs). The small neo magnet takes up minimal cabinet volume, doesn't restrict the rear-wave for dipole applications (another hint hint) and is usable next to any CRT.
Here is a cone picture. Take this one with a grain of salt, the production unit uses a different cone/surround. The phase plug is the same. The surround in the production unit goes all the way out to the perimeter of the basket hiding the glue joint. This picture doesn't show it well but the basket looks VERY nice flush mounted in a cabinet. The slight bevel on the face gives it a little extra "coolness" factor.
Overall I'm stoked! Awaiting a late April delivery schedule for my first production run. Expect the X-Generation of Exodus loudspeaker kits to follow shortly thereafter.
