"The 6NM410B is a very high output, state-of-the-art midrange product for high quality professional use. The high level of sound quality has been achieved thanks to extensive research by Eighteen Sound engineers which focused on implementing mid frequencies intelligibility. The 6NM410B can be used as a midrange in both horn & direct radiation, closed or reflex enclosures, as small as 2 liters. The extremely powerful external neodymium magnet assembly assures high flux concentration, low power compression & excellent heat exchange. Consequently, the levels of force factor & power handling are at a top professional level w/an optimum power to weight ratio. A consistent heat transfer is guaranteed by the encapsulation of the magnetic structure in the interior of the basket, offering a large contact space between the back plate & the dissipating structure. The curvilinear cone-surround, has been created using computer aided vibrational modelling software to move all undesired bell modes out of the usable frequency range. The 45 mm edge-wound voice coil assembly & terminals have been designed to minimize the moving mass while reinforcing force transmission. The 3 threaded back plate holes give the final user the opportunity to insert an external customized heat sink, if further heat dissipation is required. A proprietary humidity-block cone treatment makes the transducer suitable for outdoor use in adverse weather conditions. In addition, a special coating applied to both the top & back plates makes the 6NM410B far more resistant to the corrosive effects of salts & oxidization. Shipping Weight: 4 pounds ""HIGHLIGHT || * High Output Midrange Transducer || * Nominal Diameter 152 Mm (6 In) || * Rated Impedance 80 || * Aes Power (1) 180 W || * Program Power (2) 240 W * Peak Power (3) 480 W || * Sensitivity (4) 101.5 Db || * Frequency Range (5) 150 + 6300 Hz || * Power Compression @-10 Db (6) (18w) 0.7 Db || * Power Compression @-3 Db (90w) 1.2 Db || * Power Compression @Full Power (180w) 1.6 Db || * Max Recomm. Frequency 5000 Hz || * Recomm. Enclosure Volume + 5 It. (0.04 + 0.18 Cu.F) || * Minimum Impedance 7.3 O At 25 Degrees || * Max Peak To Peak Excursion 8 Mm (0.31 In) || * Voice Coil Diameter 45 Mm (1.77 In) || * Voice Coil Winding Material Aluminum || * Suspension Progressive Double Roll, Polycotton || * Cone Curvilinear, Paper "