JBL GTO Series GT120

12" 4-ohm Subwoofer

  • JBL GTO Series GT120


  • JBL GTO Series GT120


  • JBL GTO Series GT120

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Item #: 109GT120

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Our take on the JBL GTO Series GT120

by Steven Johnson

What's a component sub and why would I want one?

A component sub is simply a speaker that's designed to reproduce bass once it's installed in a compatible enclosure. Think about the impact of a movie soundtrack in a big theater or even in your own home HDTV setup. A component sub can add the same kind of power to the music in your car. And a car sub is not all about the boom that you hear on a street corner (although that's cool too) - you can pair a component sub with your choice of enclosure to get bass just the way you like it, from tight and punchy to fat and loose. And once you experience music in your car with a well-tuned subwoofer, you'll never go back.

JBL knows that everybody has different tastes in bass — that's why they designed GTO Series subwoofers to work great in sealed, vented, or bandpass enclosures. JBL packed over a half century of speaker-building experience into creating these GTO subs, so you can hear bass the way you like it!

The GT120 12" subwoofer boasts a polypropylene cone that's lightweight and ultra-efficient, so you won't need as much power to drive your low notes. But if you like to crank it up, the butyl rubber surround, dual 40-ounce magnets, and progressive spider ensure that this woofer won't bottom out when the going gets tough.


  • polypropylene cone with butyl rubber surround
  • dual 40-ounce magnets
  • power range 55-250 watts RMS
  • peak power 1,000 watts
  • frequency range 23-450 Hz
  • sensitivity 93 dB SPL
  • impedance 4 ohms
  • top mount depth 6"
  • sealed box volume 1.0 cubic feet
  • ported box volume 2.25 cubic feet
  • Recommended Q-Logic Box Type: 1
  • 1-year warranty

Priced per speaker

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

Features and Specs
12 -inch
4 ohms
Cone Material
Surround Material
Butyl rubber
Ideal Sealed Box Volume (cubic feet)
Ideal Ported Box Volume (cubic feet)
Port diameter (inches)
Port length (inches)
Dual Voice Coil
93 dB at 2.83 watts
Frequency Response
23 - 450 Hz
RMS Power Range (Watts)
Peak Power Handling (Watts)
Top Mount Depth (inches)
Bottom Mount Depth (inches)
6 1/2
Cutout Diameter or Length (inches)
11 5/16
Vas (liters)
Fs (Hz)
Xmax (millimeters)
Parts Warranty
1 Year
Labor Warranty
1 Year
Product Research
What's in the box?

Download owner's manual

  • One 12" woofer
  • Owner's Manual
  • Technical Data sheet
  • Warranty card
  • "JBL" sticker

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.

Enclosure Compatibility


Polypropylene Woofer Cone: The woofer cone is made with polypropylene for exceptional transient attack. The cone is light, but strong enough to maintain its shape at high output levels.

Butyl Rubber Surround: A butyl rubber surround is used to guarantee long-term reliability by rejecting moisture and ultraviolet contamination.

Progressive Spider: This woofer is made with a progressive spider. A progressive spider is used because it provides better control than a linear spider at the woofer's excursion limits.

High SPL: A long Xmax (cone excursion limit) and dual 40 oz. magnets make this woofer ideal for high output applications.

Enclosure Compatibility

Recommended Sealed Box Volume: JBL recommends a 1.0 cu/ft sealed enclosure.

Recommended Ported Box Volume: JBL recommends a ported box with an internal volume of 2.25 cu/ft. One 4" diameter x 13.31" long port should be used with a 2.25 cu/ft enclosure.

Recommended Sealed Bandpass Box Volume: JBL recommends a bandpass box with an internal volume of 3.5 cu/ft. The 3.5 cu/ft enclosure should have a sealed chamber volume of 1.5 cu/ft and a ported chamber volume of 2.0 cu/ft. One 6" diameter x 10.57" long port should be used in the ported chamber.

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JBL GTO Series GT120 Reviews

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4 out of 5

jbl g120

Written By k1, boston ma on Friday, December 27, 2013
these subs are a great buy for the price, the sound quality is great, I have it running off a 2 channel amp with 250 rms to each sub. the subs have a lot of punch and are still capable of reaching very low notes. definatly a great buy to b the loudest kid in the neihbourhood but not at a competition. I gave it a 4 because for the price and value its a lot of quality bass and durability. jbl stands up to there name in there line of competition subs. can def. give u a great massage but not capable of making u sick like my p1222's , great buy
functions great, lots of quality bass and excursion when powered properly! always give alteast 70% rms power to ure sub to prevent clipping and ruining ure subwoofers ppl! works great easy to wire and install.
not the strongest sub u can get on the market and these are sumwhat outdated but wrth the money.
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"Coolness Factor"
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