SMP-300 Sub Amplifier

 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.
Features: 

• 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) 

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 ControlThe 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. Includes 
Class D Amp TechnologyThe 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.