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Compact, and super-affordable, Sony's SA-WM20 is an easy way to add some extra bass to just about any home theater or music system. It features a built-in 50-watt amplifier and a 8" long-throw woofer for solid, punchy lows. A phase switch and crossover control let you easily match the SA-WM20's output to your other speakers. Nice features, great price!


  • 50-watt amp
  • 8" long-throw woofer
  • frequency response 28-200 Hz
  • continuously variable 50-200 Hz low-pass crossover
  • speaker-level inputs
  • line-level input
  • phase switch
  • black vinyl finish
  • 10-5/8"W x 12-3/4"H x 15-1/8"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-WM20 Reviews

Hands-on research

What's in the box?

Download owner's manual

  • 1 Powered subwoofer
  • One 6.5' Single RCA cable
  • Two 8' lengths of speaker wire
  • Operating Instructions
  • Warranty sheet
  • Important safeguards
  • Owner Registration Card

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 (28 Hz) from a compact cabinet.

Woofer: The SA-WM20 has a 8" long-throw woofer for deep, accurate bass.

Amplifier: The 8" long-throw woofer is powered by a 50-watt amplifier.

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

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


Front Panel:

  • Power Button: turns the subwoofer amplifier on or off
  • Level Control: rotary subwoofer level control
  • Cut Off Frequency: variable low-pass crossover adjustable from 50-200Hz
  • Phase Switch: allows you to select normal or reverse for best bass
  • Power Indicator: illuminates in green when the subwoofer is receiving power

Inputs and Outputs

Back Panel:

  • Line In: one RCA pre-amp level input 
  • 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.