Cambridge Audio SX-120

Powered subwoofer

  • Cambridge Audio SX-120


  • Cambridge Audio SX-120

    Angled front view with grille

  • Cambridge Audio SX-120


  • Cambridge Audio SX-120

    Direct front view with grille

  • Cambridge Audio SX-120

    Direct front view without grille

Item #: 779SX120
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Our take on the Cambridge Audio SX-120

by Dave Bar
Cambridge Audio

Why add a powered subwoofer?

A powered subwoofer gives you bass you can feel as well as hear. Our customers love the depth and impact their subs add to music and movies. We hear comments like "it brings out sounds I didn't know existed in discs I've watched a million times." Powered subwoofers aren't just for big bass that rattles your picture frames; they can also deliver tight, accurate lows. If you haven't shopped for a powered sub in a while, you might be surprised at how small they get. Look for an ultra-compact model if you want to tuck your sub away under an end table or in a corner.

Give your sound system a deep foundation

The SX-120 may be compact, but it can certainly pack a punch when needed. A built-in 70-watt amplifier helps it deliver some serious low bass performance all the way down to 34Hz. It's a perfect match for Cambridge's SX Series speaker line, and works great when used in a stereo music setup or home theater system along with the SX-50 or SX-60 bookshelf speakers.

Designed and engineered with passion

All of Cambridge Audio's SX Series speakers are carefully designed and tested at their London facility by a team of engineers fueled by their passion for incredible sound. The SX-120 uses an 8" forward-firing woofer and dual rear ports to create full-bodied, dynamic bass for all your favorite music, movies, and video games. The rigid cabinet comes with spiked feet to help keep the bass tight and well-controlled. It means you'll hear clean, detailed lows, even when you crank up the volume.

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  • bass reflex (ported) enclosure
  • 8" long-throw woofer with treated paper cone for smooth and even frequency response
  • built-in 70-watt RMS amplifier
  • frequency response 34-150 Hz
  • continuously variable low-pass 50-150 Hz crossover
  • phase switch
  • auto on/off
  • line-level/LFE (mono) input for use with home theater receiver's subwoofer output
  • matte black finish
  • 11-13/16"W x 11-13/16"H x 12-1/4"D
  • warranty: 5 years woofer, 3 years amplifier
  • Our 60-day money-back guarantee

Hands-on research from the Crutchfield Labs (what are the Labs?)

Features and Specs
Bass Reflex
Video Shielded
Woofer Size (inches)
Woofer Composition
Treated Paper
Firing Direction
Preamp-Level Inputs
Speaker-Level Inputs
Speaker-Level Outputs
Low-Pass Crossover Freq
High-Pass Crossover Freq
Phase Switch
Amplifier Output (watts)
Frequency Response
34-150 Hz
Height (inches)
Width (inches)
Depth (inches)
17 lbs
Speaker Parts Warranty
5 Years
Speaker Labor Warranty
5 years
Amplifier Parts Warranty
3 Years
Amplifier Labor Warranty
3 Years
Product Research
What's in the box?

Download owner's manual

  • Powered subwoofer
  • 6' AC power cord
  • Detachable grille
  • 4 Spiked feet
  • Installation Guide
  • Important Safety Instructions

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team — they open the box, verify contents, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.


8" Long-Throw Woofer: The Cambridge Audio SX-120 powered sub employs a custom designed 8" long-throw woofer with treated paper cone for a smooth and even frequency response.

70W Amplifier: The SX-120 powered sub use a 70W (RMS) amplifier for dynamic bass response.

Rigid  Bass Reflex Enclosure: The Cambridge Audio powered sub features a rigid MDF cabinet, expert designed to minimize standing waves and deliver deeper, tighter bass response. The enclosure features two rear-firing ports for improved efficiency and bigger bass output.

RCA/LFE Input: The powered sub has gold plated left & right RCA line-level inputs for use with receivers having a subwoofer or stereo preamp output that do not contain their own low-pass crossover. The left channel RCA input doubles as the LFE input, if your receiver has an LFE output and a built-in low-pass crossover.

Controls: The Cambridge Audio SX-120 features individual controls to tailor volume, crossover frequency. and phase adjustment.

  • Volume Control: The SX-120 powered subwoofer has a rear-panel rotary volume control to adjust the volume of the subwoofer relative to the other speakers in the system.
  • Crossover Frequency: The SX-120 offers a continuously variable low-pass filter, adjustable from 50-150 Hz.
  • Phase Adjustment: The subwoofer's phase adjustment allows you to adjust the subwoofer's phase between 0° or 180°. If the bass sounds muddy or unclear, adjusting the phase control can sometimes strengthen the bass performance.

Auto On/Off: The SX-120's Auto On/Off feature will switch the powered subwoofer On and Off automatically by signal detection. The powered sub will enter "standby" mode when there has been signal activity for 30 minutes or more.

Applications: The SX-120 is ideally suited to complement Cambridge Audio's SX series speaker line-up and other brands of speakers, adding deep and rich bass extension to your movies and music soundtracks.

Placement Options: The powered subwoofer can be placed almost anywhere in the room as bass sound is largely non-directional. For best results, place the subwoofer on the same side of the room as your front speakers. Corner placement will increase the powered subwoofer's output.

Spiked Feet: The Cambridge Audio SX-120 powered subwoofer includes four spiked feet for added stability on your carpeted floors. The spiked feet are adjustable, in case you have uneven floors. The spiked feet add 1.25" to the height of the powered sub. The powered subwoofer can be used with or without the four spiked feet, in case you have tile or hardwood floors.

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For a more in-depth review and enhanced detailed information on the Cambridge Audio SX-120, please visit the Crutchfield website product page (/ISEO-rccbcspd/p_779SX120/Cambridge-Audio-SX-120.html ).