In stockFree Shipping



If you're looking to add a little (or a LOT) of bass to your backyard, then this subwoofer kit is just what you're looking for! We have paired the 500 watt GLS8 in-ground subwoofer with the 500 watt SMP300 class D subwoofer amplifier to help you bring that bold, deep bass and full-range audio to backyards of any size. The GLS8 is a passive subwoofer that needs a dedicated subwoofer amplifier, but we took the guesswork out of the equations for you and paired it up with the 500 watt Class D SMP300 subwoofer amplifier which provides continuous, stable power but measures only 3” high so it can fit inside any equipment rack or cabinet. 

About the Subwoofer:

Get ready to rumble
Bring your landscape to life with our powerful GLS8 In-Ground Subwoofer. To immerse yourself in music’s lowest tones while enjoying your outdoor retreat, OSD Audio offers the GLS8 In-Ground Subwoofer. Since the bulk of the subwoofer is buried underground, only the port needs to appear to the outside world. But just because you can’t see it doesn’t mean you won’t know it’s there. The subterranean design brings bold, deep bass and full-range audio to backyards of any size.

• Buried subwoofer cabinet disappears into the landscape.
• Exposed vent can be primed and painted to blend into its surroundings.
• At less than 20 inches long, you can enjoy big sound with a small footprint.

Installation Tips:
• For the best quality sound place the subwoofer within 20 feet of the general listing area.
• Ensure the hooded output vent is away from the direct spray of sprinklers.
• Before burying the sub, put gravel at the bottom of the hole for drainage and levelin

About the Amplfier: 

OSD Audio’s SMP300 is a Class D digital mono subwoofer that delivers up to 500W of peak power to beef up the bass in your home theater or audio sound system. Designed for use with passive subwoofers such as in-wall subs that require external power, the SMP300 provides continuous, stable power but measures only 3” high so it can fit inside any equipment rack or cabinet. Moderately priced with high-end features, this compact sub amp enhances the low frequency sound effects on music and movie soundtracks so you’ll experience highly accurate bass and a more intense surround sound experience. The SMP300 includes variable low pass filter control for balanced and seamless sound quality as well as variable phase control for additional fine tuning. Multiple connection options include LFE input, line-level and speaker-level inputs to cover newer and old school source equipment.

Variable Low Pass Filter
A front-panel variable low pass filter allows you to adjust the upper frequency limit of the subwoofer to control the overlap of the subwoofer’s upper frequencies and the main speakers’ lower frequencies. This results in bass that complements the sound from the main speakers rather than overpowers.

Variable Phase Control
The SMP300 also includes a front-panel variable phase control knob that operates over a range from 0 degrees to 180 degrees and allows you to match the arrival times of the sound waves from the subwoofer and the main speakers. This fine-tuning results in bass that is less muddy or thumpy but rather smooth and detailed. Many amp subwoofers in this price range include a variable phase switch that does not offer the same amount of audio precision. <br >

Includes Class D Amp Technology
The SMP300 uses Class D digital amplifier technology that combines the best qualities of both Class A and B amp protocols into a highly efficient compact chassis that is ideal for budget-minded users who want a feature-rich digital sub amp that does not run hot or take up a lot of space.


  • A compact and powerful digital subwoofer amplifier for home theater applications
  • Efficient Class D digital technology runs cool under demanding loads
  • Rated at 500W peak power and 250W continuous RMS
  • Includes front-panel variable low-pass filter for balanced and accurate bass
  • Additional front panel controls include phase and volume
  • Multiple input options for older and newer receivers and pre-amps
  • Auto sensing feature turns off amp when signal is undetected
  • Dual voltage switchable (120V/230V)


Tech Specs
More Information
OSD Audio OSD Audio
Color White/ Bone/ Ivory

Subwoofer Specifications:

  • Speaker Type: 8" Burial Rated In-Ground Outdoor Subwoofer
  • Woofer: 8" Polypropylene Cone with Rubber Surround
  • Frequency Response: 28Hz-200Hz
  • Power Handling: 500 Watts
  • Sensitivity: 84 dB
  • Impedance: 8 Ohms
  • 360° Omni-directional
  • Weatherproof Impact Resistant Cabinetry
  • Exposed Vent can be Primed and Painted to Blend into its Surroundings
  • Sold as Single or Pair? Single
  • Unit Dimensions: (L x H x D) 19.75" x 28" x 15.5"
  • Weight: 32 lbs
  • Warranty: 2 Years

Subwoofer Amplifier Specifications:

  • Amplifier Type: Subwoofer
  • Amplifier Class: Digital Class D
  • Channels: 1
  • Power Handling: 60W(RMS)/ 120W(MAX) Per Channel @ 8 Ohm
  • Power Handling: 100W(RMS)/ 200W(MAX) Per Channel @ 4 Ohm
  • Frequency Response: 20Hz-160Hz +/-1 dB THD: 1%
  • Variable Crossover: 35Hz-160Hz
  • Variable Phase Switch: 0 to 180 Degrees
  • Impedance: 8 Ohm and 4 Ohm Stable
  • Signal to Noise Ratio: 95 dB
  • 12V Trigger Mode
  • Inputs: Speaker (High) Level / Signal (Low) Level RCA
  • Rack Mountable: 1U Rack Space Style / Mounts Included
  • Dimensions (L x H x D): 8.5" x 1.75" x 9.8"
  • Weight: 4 lbs
  • Warranty: 2 Years
California's Proposition 65