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  GR Research Drivers
12" servo-enabled subwoofer driver

We now sell three GR Research subwoofer drivers which have been designed to work with our Direct Servo technology. These drivers have a custom sensing coil which allows them to be used with custom designed Direct Servo amplifiers.

While these three drivers are identical in appearance, details of the motor are different to cater to different applications.

GR SW-12-04
Designed for a sealed box with 1.5 cu ft volume

GR SW-12-08FR
Designed for a open baffle and infinite baffle applications. 8ohm nominal impedance. Recommended for running a pair with HX300-12OB configuration

GR SW-12-16FR (reference only)
Designed for a open baffle and infinite baffle applications. 16ohm nominal impedance.

Single and double driver options

The first two GR drivers are designed for a sealed box with 1.5 cu ft of volume per driver. GR SW-12-08 is designed to run two drivers on the one amp. Each driver has a nominal 8 ohm impedance, and are intended to be connected by a parallel connection, resulting in a 4 ohm load to the amplifier. The dual driver option will have additional output as well as lower distortion for a given output level. A 3 dB gain in efficiency is gained, thereby yielding a 3 dB increase in continuous maximum output. For short burst transients, 6 dB increase can be achieved.

Open baffle and infinite baffle options

To achieve higher output in an infinite baffle or dipole configuration, SW-12-16FR has been designed so that 2 or 3 drivers can be connected to a single amplifier. The higher 16 ohm impedance allows a parallel connection. With 2 or 3 drivers, high output can be achieved even with an open baffle.

Conventionally, drivers with a high Qts are used in these applications to achieve the desired frequency response. With Direct Servo, a much higher degree of control of the cone is maintained than with a conventional non servo driver.

Driver comparison

The GR drivers use a lower mass paper cone, which has a slightly better transient response. The result is slightly better dynamics. At higher output, due to less cone stiffness, the sound may become softer due to the pressure placed on the cone.

The GR drivers also have a more extended response, allowing a higher crossover point if desired.

The performance can be described as "different" rather than superior or inferior.

Thiele/Small Parameters
Model GR SW-12-04 GR SW-12-08FR GR SW-12-16FR (reference only)
Enclosure size 1.5 cu ft sealed Infinite baffle / open baffle Infinite baffle / open baffle
fs 25 Hz 27.4 Hz 28.3 Hz
BL 13.7 11.2 14.7
Mms 138 g 112 g 108 g
VAS 100 L 100 L 100 L
Qms 4.308 3.201 2.80
Qts 0.321 0.747 0.875
Sd 490 cm2 490 cm2 490 cm2
Re 3 ohms 6.2 ohms 14 ohms
Xmax 16 mm 16 mm 16 mm

These drivers are available for purchase separately to use in a non servo configuration with the intent to upgrade to a servo sub with the purchase of our servo amplifiers in the future. This will suit those who already have an amplifier and crossover. If you are starting from scratch and don't already have an amplifier and crossover, then we recommend that you purchase one of our Direct Servo kits.

  Description: GR drivers Price  
  GR SW-12-04 - 4 0hm - 12" driver $229 buy it now
  GR SW-12-08FR - 8 0hm - 12" driver (IB/dipole) $229 buy it now