# OSD Audio SMP300 Mono Subwoofer Amplifier - 300W

Enhance your home audio experience with the OSD Audio SMP300, a powerful 500W mono-channel Class D subwoofer amplifier engineered to deliver deep, clean bass with outstanding efficiency.

Perfect for home cinema systems, custom installations, or high-end two-channel audio setups, this compact yet robust amplifier is tailored for audiophiles who want to power a passive subwoofer with precision and control.

With its rack-mountable design and advanced signal sensing, the SMP300 integrates seamlessly into AV systems.

Whether you're upgrading a home theatre or adding low-frequency impact to a multi-room setup, this amplifier offers versatile performance with intuitive controls and flexible inputs.

**FEATURES**

-   **High Power Output**: Delivers up to 500W peak and 300W RMS, driving even large passive subwoofers for room-filling bass.
-   **Class D Efficiency**: Class D digital amplification ensures cooler operation and reduced power consumption without compromising on performance.
-   **Variable Crossover & Phase Control**: Fine-tune your bass response to suit your room acoustics and speaker setup with adjustable crossover and 0–180° phase switch.
-   **Multiple Input Options**: Includes both line-level and speaker-level inputs, making it compatible with a wide range of audio systems.
-   **Auto-On Signal Sensing**: Automatically powers on when a signal is detected and shuts off after inactivity, improving energy efficiency and convenience.
-   **Rack-Mountable Design**: Fits neatly into standard AV racks with removable side brackets, perfect for professional or custom home installations.
-   **Subwoofer EQ Switch**: Enhances low-end performance with a tailored EQ setting for even deeper bass output.
-   **Heavy-Duty Build Quality**: Solid construction with reliable components ensures long-term durability and consistent performance.
-   **Quiet Fan Cooling**: Internal fan keeps the amp cool under load while maintaining quiet operation.
-   **Protection Circuitry**: Built-in safeguards protect against short circuits, overheating, and overloading, giving you peace of mind.

###### What You Get

-   1 x SMP300 Amplifier
-   1 x Power Cable

###### Specifications

-   **Amplifier Type:** Subwoofer
-   **Amplifier Class:** Digital Class D
-   **Channels:** 1
-   **Power Output:** 500 Watts @ 4 Ohm
-   **Power Handling:** 8 Ohm RMS Rating (Watts): 150 Watts
-   **Power Handling:** 4 Ohm RMS Rating (Watts): 250 Watts
-   **Frequency Response:** 20Hz-160Hz +/-1dB THD: 1%
-   **Variable Crossover:** 35Hz-180Hz
-   **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):** 413mm x 76mm x 235mm
-   **Weight:** 3.2kg
-   **Warranty:** 2 Years

## Details

- **Price:** 499.0 GBP
- **Vendor:** OSD Audio
- **Type:** Amplifiers
- **Tags:** BLACK5, SALE10

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 499.00 GBP | In stock |

## Images

- OSD Audio SMP300 Mono Subwoofer Amplifier - 300W - K&B Audio
- OSD Audio SMP300 Mono Subwoofer Amplifier - 300W - K&B Audio
- OSD Audio SMP300 Mono Subwoofer Amplifier - 300W - K&B Audio
- OSD Audio SMP300 Mono Subwoofer Amplifier - 300W - K&B Audio
- OSD Audio SMP300 Mono Subwoofer Amplifier - 300W - K&B Audio
- OSD Audio SMP300 Mono Subwoofer Amplifier - 300W - K&B Audio

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> Source: [K&B Audio](https://www.kbaudio.co.uk/products/osd-audio-smp300-mono-subwoofer-amplifier-300w)
> Updated: 2026-04-29