Q-Logic QB-115.3

Single 15-inch bandpass subwoofer box

  • Q-Logic QB-115.3


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Item #: 044QB1153

Review Summary

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Our take on the Q-Logic QB-115.3

by Steven Johnson

Why choose a Q-Logic enclosure? For their musical performance and their unbeatable construction. Thanks to reliable locking-joint construction and exceptionally strong adhesive, these boxes are virtually indestructible.

Q-Logic's QB-115.3 bandpass subwoofer box is designed to house a single compatible 15" woofer. It's made from 5/8" medium density fiberboard for strength and is impeccably upholstered with durable grey carpet. You can watch your subwoofer work through the large Plexiglas window. Screws are included for your subwoofer. The box comes with wires for the internal connections (with quick-slides attached) and a terminal cup with gold-plated binding posts.

The port tubes are pre-installed. In most cases, you will need to cut the port tubes to length to tune the box to the subwoofer you've selected; detailed instructions are included to help you determine the proper lengths. This box will fit in trunks, hatchback spaces, and the rear area of most SUVs and vans.

Key Specifications:

  • houses one 15" subwoofer
  • 5/8" medium density fiberboard
  • spring post terminals
  • 2.09 cubic feet internal volume (ported section), 2.06 cubic feet internal volume (sealed section)
  • box dimensions:
    • height: 18-1/4"
    • width: 30"
    • top depth: 18-1/8"
    • bottom depth: 18-1/4"
  • warranty: 1 year
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Hands-on research from the Crutchfield Labs (what are the Labs?)

Features and Specs
Number of Speakers 1
Speaker Size 15
Cutout Diameter or Length (inches) 13 11/16
Maximum Speaker Depth (inches) 9-11/16
Box Volume (cubic feet) 4.15
Height (inches) 18-1/2
Width (inches) 17-15/16
Depth (inches) 28-5/8
Second Depth (inches) 28-5/8
Wood Thickness (inches) 5/8
Speaker Wire Connectors Spring Post
Box Color Dark Gray
Box Finish Carpet
Parts Warranty 1 Year
Labor Warranty 1 Year
Port Measurements
Number of Ports 3
Diameter (inches) 4
Length (inches) 12
Product Research
What's in the box?

Download owner's manual

  • Single bandpass enclosure
  • One 16-1/4" Square Plexiglas window (0.386" thick)
  • One 29" length of speaker wire (has 0.205" female quick-slides on both ends)
  • Three 12" cardboard port tubes (each tube has a 4" diameter)
  • 3 Silver plastic port flanges
  • 33 Self-tapping screws
  • Installation Instructions (has port tuning chart)

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.


Materials: The box is constructed of 5/8" MDF (medium-density fiberboard). MDF resists flexing and has anti-resonant qualities. The 0.386" thick Plexiglas window is 16-1/4" square and is held in place with 16 screws (only 5 screws secure the Plexiglas when received). Three 4" diameter cardboard port tubes (length=12") are included, and should be trimmed according to the supplied Port Tuning Chart. The supplied silver plastic port flanges mount to the top of the woofer box.

Note: Due to the position of the port tubes in the enclosure, the mounting depth can be limited for a top-mounted woofer with a large magnet. If the tubes are shortened (according to the tuning chart), it is possible that the available woofer mounting depth may increase.

Design: The enclosure consists of a 2.09 cu/ft ported chamber, and a 2.06 cu/ft sealed chamber. The edges of the front, back, top and bottom use mitered joints, so there's 50% more surface area for the special glue that bonds them. For strength, the woofer mounting panel and the Plexiglas mounting panel are mounted using a full dado groove. The enclosure is covered with durable gray carpet.

Spring Post Terminals: This enclosure has a pair of spring post terminals located on the rear of the enclosure. The spring posts will accept bare wire, pin connectors, banana plugs or dual banana plugs. The terminal cup is recessed so the spring posts do not protrude from the back panel.

Brackets: Brackets (not included) are recommended for more secure mounting.

Warranty Note: The Plexiglas window is not covered under warranty.

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Q-Logic QB-115.3 Reviews

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4 out of 5

Good box

Written By pw91686, Mobile, AL on Monday, February 07, 2005
Crutchfield Customer Review (What's this?)
This is a very good box. I have an Audiobahn 15" Immortal Series sub in it and it works really well. If you don't have the time to make your own box, I would recommend this one. Make sure it fits in the trunk though, it barely fit in mine. But the sound is really good. Very easy to put together. A little pricy, but you get what you pay for...
112 out of 149 people found this helpful
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For a more in-depth review and enhanced detailed information on the Q-Logic QB-115.3, please visit the Crutchfield website product page (/ISEO-rccbcspd/p_044QB1153/Q-Logic-QB-115-3.html ).