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SW-12-08 Servo Sub Woofer  SOLD OUT

The 8 ohm version has been phased out. In the future multiple woofer subs will be handled by multiple channel amps and the SW-12-04 woofer.

The SW-12-08 sub was specifically for the discerning audiophile looking for the ultimate in accuracy and sound quality. It is meant to be used with the Direct Servo plate amps. Direct Servo is a patented technology that is far more effective than any other servo control systems of the past. 

No other sub-woofer system on the market offers this level performance. With this sub-woofer system you will hear articulation and resolution in the low bass region far beyond standard passive systems regardless of how well the woofer is made. Distortion levels are also extremely low and well below other sub-woofer designs. 

The SW-12-08 gives new meaning to the terms fast bass. Fast bass has been a debatable term but really refers to a drivers ability to return back to a resting position. Any other sub must rely on the suspension alone to allow it to return back to a resting position. Any sub capable of playing down to the 20Hz range will also need a very heavy cone and a really low Fs. The heavy cone and its stored energy from the inertia of its movement make it difficult to quickly return to the resting position. The Direct Servo controlled sub can make use of a much lighter weight cone as the servo system will virtualize the parameters and add output as needed to maintain a flat response to below 20Hz even with a light weight cone that has a higher Fs. Not only does the light weight moving mass minimize the inertia but the Direct Servo control system effectively slams on the brakes electrically to much more quickly bring the woofer back to its resting position.

If you need or want more output levels than you can get from a single 12" woofer we don't necessarily recommend going to a larger and heavier (drawback) woofer just to displace more air. We recommend using more 12" woofers instead. They have a lighter weight moving mass for even better control. The smaller 12" woofers also help keep box volumes down to manageable levels.

The SW-12-08 is an 8 ohm woofer designed to be used in pairs (paralleled) on a single Direct Servo amplifier. So you can get double the output levels without the added expense of additional amplifiers. With two woofers sharing the load equally, higher SPL levels can be reached, while still maintaining moderate excursions keeping distortion even lower still.

Due to the electrical control of the Direct Servo system a larger than typical optimal box can be used to allow lower levels to be reached with less amplified gain. We recommend a sealed enclosure in the 1.5 cubic feet range (per woofer). Ported enclosures can also be used with the Direct Servo system for additional output levels.

 SW-12-08 parameters:

Mechanical Parameters:

  • Fs =  23.1 hertz
  • Qms = 4.04
  • Vas = 4.085 cu.ft or 115.67 liters
  • Cms = 0.059 in/Ib
  • Mms = 4.949 oz or 140 grams
  • Rms = 11.122 Ibs/sec
  • Xmax = 16 mm
  • Sd = 76 or Dia = 9.83 in or 250 mm

Electrical Parameters:

  • Qes = 0.370
  • Re = 6 ohms
  • Z = 8.0 ohms nominal
  • BL = 18.2
  • Pe = 200.0 watts (conservitive rating)

Combination Parameters:

  • Qts = 0.339
  • Sens = 87.7 dB (2.83 V)


Direct Servo amps are available right here.


Your Price: $149.00
Item Number: SW-12-08
Manufacturer: GR Research
Manufacturer Part No: SW-12-08

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