Blaupunkt GTb 8A

8" 75-watt powered subwoofer

  • Blaupunkt GTb 8A


Item #: 023GTB8A

Review Summary

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Our take on the Blaupunkt GTb 8A

by John Pollard

Who needs a powered subwoofer?

To produce bass, you need a sub, an enclosure, and an amplifier, and it can be little tricky to match them all up. A powered sub eliminates all the hassle, as the manufacturer designs the enclosure to house the sub and amp together. This all-in-one solution is especially useful in smaller vehicles, where there's no room to mount a separate amp, or in any vehicle where you need every bit of cargo space. Powered subs range from small, flat boxes that fit under your seat to larger boxes that go in your trunk.

Get ready to rock with Blaupunkt's GTb 8A powered subwoofer. You'll feel the bass you've been missing as the 8" spun-paper woofer pumps out the low-end thump. Its built-in 75-watt RMS amplifier keeps you from having to match up a separate amplifier — you just wire this sub up to your system and you're good to go. At under 11" deep, this compact sub will fit in some pretty tight places.

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  • powered subwoofer with 8" woofer
  • built-in 75 watt RMS amplifier (150 watts maximum)
  • frequency response: 30-200 Hz
  • dimensions: 10-1/2"W x 10-3/8"H x 11-5/8"D1 x 8-7/8"D2
  • warranty: none (Crutchfield's 60-day satisfaction guarantee applies)
  • Our 60-day money-back guarantee

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

Features and Specs
Enclosure Type Ported
Finish Material Carpet
Grille Metal Rods
Connector Type RCA/Molex
Bi-amp Inputs No
Woofer Size (inches) 8
Woofer Material Spun Paper
Passive Radiator ---
Width 10-1/2"
Height 10-3/8"
Depth 11-5/8"
Second Depth 8-7/8"
Parts Warranty 60 Days
Labor Warranty 60 Days
Frequency Response 30-200
Amplifier Power (RMS) 75 watts
Maximum Wattage 150 watts
Sensitivity N/A
Impedance N/A
Second Voice Coil Impedance N/A
Crossover Point 70-200
Product Research
What's in the box?

Download owner's manual

  • Subwoofer enclosure loaded with one 8" Woofer and built-in amplifier
  • 7.5 amp ATO fuses (installed)
  • Wiring harness (16.5' Power and speaker level input/ 3' Ground)
  • Instruction manual

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.


Overview: The GTb 8A amplified subwoofer features a 75-watt RMS (150-watts max) amp and an 8" subwoofer housed in a ported enclosure.

Auto Turn-on: The amplifier automatically turns on when it detects a signal on the line or speaker level inputs. After approximately 60 seconds with no input signal, the amplifier will turn off.


  • Level: rotary dial to set the amplifier input gain; variable from 300mV to 8V for the line level inputs and 700mV to 19V for the speaker level inputs
  • Frequency: rotary dial to set the low-pass crossover frequency; variable from 70 Hz to 200 Hz
  • Phase: rotary dial to set the subwoofer phase; variable from 0° to 180°


  • Power: the included harness has two 16.5' power and two 3' ground wires (all should be connected and the power wires should be fused at the battery)
  • Speaker Input: the included harness also has 16.5' left and right speaker level input wires
  • Line Input: stereo RCA jacks


  • Width: 10-1/2" (including 5/8" protrusion of the control knobs)
  • Height: 10-3/8"
  • Depth (bottom): 10-5/8" (the grille, two steel rods, adds approximately 1" to the depth)
  • Depth (top): 8-7/8"
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Blaupunkt GTb 8A Reviews

Average Customer Review:

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5 out of 5


Written By Bob, Lincoln, NE on Monday, December 24, 2012
Crutchfield Customer Review (What's this?)
I upgraded my auto stereo system with component front & rear speakers & equalizer yet was lacking the low bass and decided to try this sub. I primarily listen to lower volume settings and this sub is just right. Easy to install and provides the much needed "bottom end".
Decent price & easy install & great sub sound.
2 out of 2 people found this helpful
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5 out of 5

Great Product!

Written By Nick, Gloucester Va on Sunday, December 02, 2012
Crutchfield Customer Review (What's this?)
Sounds great! It isnt going to rattle windows. But, at 75 watts and a small enclosure i wasnt expecting much. It sound a lot stronger than its size suggests. I put this in a 81 Rabbit 1.6d and it left a a lot of room in the hatch area. This sounded good with : late 70s jazz, Obituary, Lamb of God, Slayer, Ganksta NIP, NWA, Getto Boys.
Small size, appealing construction, tuneability
Tuning switches are a target waiting to be hit. Should have been recessed.
2 out of 2 people found this helpful
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For a more in-depth review and enhanced detailed information on the Blaupunkt GTb 8A, please visit the Crutchfield website product page (/ISEO-rccbcspd/p_023GTB8A/Blaupunkt-GTb-8A.html ).