The top of the line EP-2 series is the big brother to the smaller single woofer EP-4 series. They are the top of our line and designed to play louder than the 4 series and go lower down to 20Hz in the bass versus 26Hz on the 4 series. They are also 2 Db more efficient running from 96Db when single amped - 99Db when triamped. Both feature a 3-way 4-driver design. Both the EP-2.4 & EP-2.8 use two Emerald Physics 15" carbon fiber woofers that can extend to 20Hz when used with one of our bass extension equalizers. Both can be run with one amp and come with a 3-way full range crossover. Both use a 12" midrange and coincident tweeter for superb imaging. They are 51" high. They can be looked at as a EP-4 series with dual 15" woofers instead of one. The EP-2.4 and EP-4.4 are the same while the 2.4 has a second Carbon fiber 15" woofer. The EP-2.8 and EP-4.8 are the same with the addition of one woofer in the EP-2.8. Both the EP-2.4 and EP-2.8 use the same two Emerald Physics 15" Carbon Fiber woofers. The EP-2.4 uses a paper cone 12" midrange with our new upgraded Poly compression tweeter. The EP-2.8 steps up to our 12" Carbon Fiber midrange along with our top of the line Neo tweeter. The EP-2.8 also gets a step up crossover with upgraded parts. Both models extend to 35Hz with no equalization and 20Hz by adding our BOM or one of the two DSP crossover/equalizers. Both models can be run from a single amp and come with a full range crossover. They can also be biamped or triamped for even improved sonics. 2 series speakers compete with speakers selling for up to $30k and offer amazing sonics combined with fabulous dynamics and a "you are there" live sound rarely found in speakers at close to their Internet Direct prices.