Here it is The results for the final subwoofer out of the 5 commercial subs I tested early in the spring of this year. The Epik Empire!
Let me go ahead and say that this one was saved for last due to there being quite a bit of extra effort and work involved with reviewing it. Most of this due to it being a dual opposed subwoofer. I wanted to make sure it was right. Not soon after I mentioned that I would be testing one I received a pm from Chad the founder of Epik wishing to speak with me about what would be taking place. He was justifiably concerned about it getting a fair shake in the tests due to the dual opposed design of the subwoofer. I already had some concerns about this myself and had been talking with some notable subwoofer designers about how to handle it.
At this point let me explain the issue simply. A dual opposed subwoofer will always have one or both of the drivers further away from the microphone than a regular subwoofer which usually has a single driver and maybe a port or 2 radiating from a single surface. If you take 2 drivers and mount both on a single face of the subwoofer you can then aim that face at the microphone and the drivers end up roughly 2 meters (In our case) away from the microphone. Now take the same 2 drivers and place one of them facing the other direction on the back of the enclosure and about 20 behind the other. Its contribution at the microphone will be somewhat diminished. Even though you have the same 2 drivers, amplifier, and enclosure volume and alignment the SPL delivered to the single measurement point will be less than the subwoofer that is allowed to aim all or at least most of it's radiation at the microphone. If you have both drivers side firing so that they are equidistant from the microphone you will have the same issue still with advantage maintained by the subwoofer that can aim most of its radiation directly at the microphone. Now this holds true, if you take a single point measurement. However if you take many measurements at various points around the subwoofer the results will even back out as the dual opposed subwoofer will have more uniform 360deg power distribution. Unfortunately there is simply no feasible way for me to do a full polar response work up on every sub I test. It would be ideal but will simply be way too much work. Any subwoofer with radiation from multiple faces is subject to this issue. However ports or passive radiators contribute most of their output over a fairly narrow range, while a dual opposed sub has all radiation from both points covering the entire useful range of the device, so this is a much larger concern in that case. After quite a few emails back and forth with various people I decided on a course of action to investigate the issue and if need be develop a compensation factor for the Empire and other dual opposed subwoofers. What followed was a large amount of work that eventually lead to me becoming convinced of the necessity of and the development of a compensation file for the Empire in order for it to get a fair shake in the output testing. That effort is far too involved to go into here. It will end up being an article unto itself that I will put together in a few days time and will end up hosted on Data-Bass.
One other thing that delayed things a bit was that the first Empire that I purchased ended up developing a buzz or rattle somewhere along the line that was excited by frequencies near 90hz at loud output levels. I determined that it was not the drivers, a driver dust cap, a loose mounting screw or 2, or anything to do with the amplifier. Nor was it some internal wiring or other part making contact with the back of the cones. It appeared to be the enclosure itself although I found it to be very inert and solid feeling and I could not find any obvious issue with any bad seams or anything loose inside. Thankfully Chad sent a replacement under warranty, which technically he did not have to do since I had disassembled it while looking for the problem. (I never did hear what it was.) The second unit was without issue. Kudos to Epik for standing behind their product and honoring the warranty. Thanks.
Alright with that out of the way let's get down to the tests and review.
The Epik Empire is a sealed subwoofer design utilizing 2 long throw 15 drivers in a dual opposed configuration that places one driver on each side of the enclosure. Epik calls this Parallel Drive. Both drivers operate in phase with each other and cover the full useful frequency range of the subwoofer. This type of driver configuration has one large benefit in that the opposing forces of the 2 drivers on the enclosure cancel out each other which results in an almost vibration free subwoofer even when the subwoofer is working very hard. The amplifier is an efficient class D design rated at 600w rms and 1500w short term. It features the usual controls: On/off/auto switch, adjustable crossover 50-150hz, a crossover bypassed LFE input, a phase control and input gain adjustment. It also features balanced XLR inputs which I particularly like and even offers both 120v and 240v operation. It does not however have onboard user adjustable EQ or room compensation. Many subwoofers rely on today's advanced software built into a receiver to take care of that though. The enclosure is 1 thick material as are the cloth covered detachable grills. Both sport a nice looking 1 radius edge. The finish is a simple black laminate. The whole deal weighs in at a hefty 120lbs or so and the external dimensions are 22H x 18W x 24 D. It is not a comfortable 1 man dead lift and carry for most due to not only the weight, but also the size and large smoothly rounded over corners. There is a user applicable Epik logo that comes with the subwoofer and it is listed as designed and assembled in the good old US of A. Epik lists the response as 20-300hz +/-3.5db The price is $799 in singles or you can get a solid discount if you buy in multiples. My cost to my door with freight shipping came in at $799 plus $139 shipping for a grand total of $938. The subwoofer is delivered by freight truck and the packaging is very thorough, with little likelihood of damage occurring in transit, barring some catastrophic event or pure negligence by the shipper.
The overall build quality of the cabinet and the amplifier were very good. The amplifier in particular had a solid and high quality look and feel. The cabinet is heavy and inert. The drivers I examined and they appear to be of good quality as well. They are not particularly flashy with modest foam half roll surrounds, black Kevlar impregnated paper cones, a stiff inverted dust cap, and a stamped steel frame, but the motors are fairly hefty and of large diameter. There is what appears to be a 2 diameter voice coil and a single moderate sized spider. There is no pole vent since the drivers are virtually back to back once mounted in the cabinet. These are cost effective drivers but it seems that the money in them was spent where it counts, a strong motor with plenty of force and the cone and suspension system. Of course the other thing to note here is that there are 2 of the drivers in the cabinet. Multiple drivers can many times outgun a single much more expensive and heavy duty driver simply because the sharing of the load reduces the demands on each tremendously.
Overall the first impression I got from this subwoofer upon receiving it was that it was a solidly built and engineered product, using quality components, with the money spent where it counts most.
Please excuse my photography skills or lack thereof everyone....