Dayton Audio Ultimax UM8-22

• 8" (20cm) subwoofer
• 16 mm XMAX makes this subwoofer one of the highest excursion 8-inch subwoofers on the market
• Thick, one-piece Nomex honeycomb cone with woven high-performance glass fiber
• Tall-Boy rubber surround for extra-long linear deflection without reducing the cone surface
• Two gear rings with linear stiffness limit distortion and rocking
• 300 watts RMS power handling
• Black anodized aluminum former and black pole improve heat dissipation
•   Dual 2-ohm, 2-layer copper voice coils

Product Details

• To increase power handling, improve thermal management and reduce power compression, Dayton Audio has equipped the Ultimax series with large, black anodized coil formers and vented pole pieces, under-spider ventilation and dual-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 the driver surface even during extreme excursions. The thick, one-piece Nomex honeycomb cone is covered with woven, heavy-duty glass fibers, creating an ultra-rigid surface that resists deformation.
• A large copper sleeve and copper pole cap in the motor reduce energy storage through inductance, with the side effect of lowering distortion for a "faster" response. Large, double-stacked, high-energy magnets do the heavy lifting, bringing the Qts to a level where Ultimax subwoofers can be used in vented or sealed enclosures.

housing recommendations

• Closed 10 liters, f3 of 49 Hz with a QTc of 0.8 Qtc
• bass reflex 21 liters  tuned to 30 Hz with a 25cm wide and 2.5cm high slot port, the  76.2cm long, which gives an f3 of 30 Hz

Characteristics

• woofer series: Ultimax Series
  
• Nominal diameter:  8"
  
• Load capacity (RMS): 300  watt
• Load capacity (max):  600 watt
• Impedance (Z) :  2+2 Ohm
• Sensitivity:  84.2 dB @ 2.83V/1m
• Frequency response:  30 - 800 Hz
• Voice coil diameter:  2"
• DC resistance (Re): 4.2  ohm
• Voice coil induction (Le) : 1.14 mH
• Resonance frequency (Fs):  31.6 Hz
• Mechanical quality (Qms): 2.51
• Electrical quality (Qes): 0.75
• Overall quality (Qts): 0.58
• Moving mass (Mms): 74.5g
• compliance of the suspension (Cms)  : 0.33 mm/N
• Membrane area (Sd): 211.2 cm²
• Displacement volume (Vd): 359.1 cm³  
• Strength factor (BL): 9.1 Tm
• Equivalent volume (Vas): 21.30  liter
• Maximum deflection (Xmax): 16.0 mm
• Membrane material: Nomex
• beading material:  rubber
• Voice coil wire material: copper
• Voice coil mold material: Aluminum
• Basket / frame material:  cast aluminum
• Magnet material: Ferrite
• Outer diameter: 21cm
• Total depth:  14.3cm
• Cutout diameter:  19.7cm
• Mounting holes:  8