Dayton Audio - UM8-22 - 8" Ultimax DVC Subwoofer 2 Ohms Per Coil

Dayton Audio's Ultimax Series DVC subwoofers are purpose-built to move air and create clean, articulate, fast bass. Optimized for small enclosures and with over 1-1/4" of throw, the UM8-22 8" subwoofer is perfect for providing deep bass without taking up much space. Experience the apex of subwoofer design. Key Features  
16 mm Xmax makes this one of the highest excursion 8" subwoofers on the market Thick, one-piece Nomex honeycomb covered cone with woven heavy-duty glass-fiber Tall-boy rubber surround for extra-long linear excursion without reducing cone surface area Dual linear stiffness spiders limit distortion and rocking modes 300 watts RMS power handling Black anodized aluminum former and black pole improves heat dissipation Dual 2 ohm, 2-layer copper voice coils  
If you want outrageous amounts of bass, you gotta move some air The Ultimax Series of dual voice coil subwoofers, from Dayton Audio, are not for the faint of heart. Built using the latest in subwoofer technology, Ultimax subwoofers are the pinnacle of low frequency driver design. An Ultimax subwoofer tests the strength of your foundation with fast, articulate, gut-wrenching bass.  
 
The versatility you need for mobile, home, or pro subwoofer excellence Dual 2 ohm voice coils allow for stereo 2 ohm and mono 1 ohm wiring configurations when connecting to high current car audio and professional audio amplifiers to extract maximum power. For home audio applications, simply wire the voice coils in series for a benign 4 ohm load for greater amplifier compatibility.  
 
Built to produce massive low frequency output and keep on doing it To improve power handling, increase thermal management, and reduce power compression, Dayton Audio designed the Ultimax Series with large black anodized formers and vented pole pieces, under-spider ventilation, and two-layer copper voice coils.  
Over 1-1/4" of travel (.67" Xmax) is kept completely linear through the use of dual spiders that also limit distortion and rocking modes. "Tall-boy" rubber surrounds with integrated gaskets maintain driver surface area during extreme excursion moments. The thick, one-piece Nomex honeycomb cone is covered with woven, heavy-duty glass fibers creating an ultra-stiff surface that resists deformation.  
 
A strong motor takes you to wherever you want to be A large copper sleeve and copper pole cap in the motor reduce energy storage from inductance, with the side benefit of lowering distortion for "faster" response. Large dual-stacked, high-energy magnets handle the heavy lifting and bring Qts down to a level where Ultimax subwoofers can be used in vented or sealed cabinets and enclosures.  
Cabinet recommendations: • Sealed 0.35 cubic ft. (net internal), f3 of 49 Hz with a 0.8 Qtc alignment • Vented 0.75 cubic ft. (net internal, not including driver or port volume) tuned to 30 Hz with a 10" wide by 1" high slot port that is 30" long, which yields an f3 of 30 Hz  
Product Specifications Nominal Diameter   8" Bolt Circle Diameter   7.75 Moving Mass Of Diaphragm (Mmd)   74.5 Power Handling (RMS)   300 Watts Power Handling (MAX)   600 Watts Impedance   4Ω Frequency Response   30 to 800Hz Sensitivity   84.2dB 2.83V/1m Voice Coil Diameter   2" Thiele-Small Parameters Resonant Frequency (Fs)   31.6Hz DC Resistance (Re)   4.2Ω Voice Coil Inductance (Le)   1.14mH Mechanical Q (Qms)   2.51 Electromagnetic Q (Qes)   0.75 Total Q (Qts)   0.58 Compliance Equivalent Volume (Vas)   0.75ft³ Mechanical Compliance of Suspension (Cms)   0.33mm/N BL Product (BL)   9.1T·m Maximum Linear Excursion (Xmax)   16mm Surface Area of Cone (Sd)   211.2cm² Materials of Construction Cone Material   Nomex / Glass Fiber Surround Material   Rubber Voice Coil Wire Material   Copper Voice Coil Former   Aluminum Basket / Frame Material   Cast Aluminum Magnet Material   Ferrite Mounting Information Overall Outside Diameter   8.27" Baffle Cutout Diameter   7.44" Depth   5.65" # Mounting Holes   8 Optimum Cabinet Size (determined using BassBox 6 Pro High Fidelity suggestion) Sealed Volume   0.35ft³ Sealed F3   49Hz Vented Volume   0.75ft³ Vented F3   30Hz