Skip Navigation

Crank up the bass with Sony's affordable SA-WM40! Its potent 120-watt amp drives a 12" long-throw woofer to pump out deep, satisfying lows, and keep you on the edge of your seat with home theater thrills. The phase switch and crossover control let you easily match the subterranean sounds to your other speakers. An easy addition to any home theater or stereo system!


  • 120-watt amp
  • 12" long-throw woofer
  • frequency response 20-170 Hz
  • continuously variable 50-170 Hz low-pass crossover
  • speaker-level inputs
  • line-level input and output
  • signal-sensing power on/off
  • phase switch
  • black vinyl finish
  • 14-1/4"W x 16-7/8"H x 16-1/2"D
  • warranty: 1 year

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.

Sony SA-WM40 Reviews

Hands-on research

What's in the box?

Download owner's manual

  • 1 Black powered subwoofer
  • 6.5' Mono RCA cable
  • Two 8' lengths of speaker wire
  • Operating Instructions
  • Warranty sheet
  • Important Safeguards

Product Research

Inputs and Outputs


Advanced SAW Design: Combining a specialized speaker for deep bass with a built-in amplifier to provide power, this component features Sony's patented subwoofer design. In addition, this Super Acoustically Loaded product provides bass all the way down to the lowest musical frequencies (20 Hz) from a compact cabinet.

Woofer: The SA-WM40 has a 12" long-throw woofer for deep, accurate bass.

Amplifier: The 12" long-throw woofer is powered by a 120-watt amplifier.

Surround: For a smoother response and improved durability, the woofer uses a rubber surround.

Bass Port: There is a rear-firing bass port for improved bass response.

Auto Power On/Off: This feature turns the amplifier on when a signal is sensed and turns the amplifier off if no signal is received for a period of seven minutes.


Front Panel:

  • Power Button: Turns the subwoofer amplifier on or off.

Back Panel:

  • Level Control: Rotary subwoofer level control.
  • Cut Off Frequency: Variable low-pass crossover adjustable from 50-170Hz.
  • Phase Switch: Allows you to select normal or reverse for best bass.
  • Power Save Switch: Allows you to select Auto or Off. In the Auto position, the Auto Power On/Off feature is engaged. In the Off position, the Auto Power On/Off feature is disengaged.

Inputs and Outputs

Back Panel:

  • Line In/Line Out: RCA pre-amp level input and output
  • Speaker-Level Input/Speaker-Level Output: Spring clips for speaker-level input and output

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 verify what’s in the box, 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.