MB Quart RLP-304

300W 12" Reference Series Dual 4 ohm Low-Profile Subwoofer

MB Quart
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Product videos

• 600W Peak
• 300W RMS
• Injection Molded Polypropylene Cone
• Foam Surround
• Recommended for Sealed Enclosures

Learn more about the rlp304

We apologize

This item has been discontinued

Product Highlights

• 600W Peak
• 300W RMS
• Injection Molded Polypropylene Cone
• Foam Surround
• Recommended for Sealed Enclosures


MB Quart

Authorized dealer

  • 12" Dual 4 Ohm Reference Series Shallow Mount Subwoofer
  • Power Handling:
    • Peak: 600 watts
    • RMS: 300 watts
  • Impedance: Dual 4 Ohm
  • Injection molded polypropylene cone woofer
  • Foam surround
  • Shallow mount for small and compact installations
  • Recommended use in sealed enclosures
  • Dual voice coils
  • Frequency response: 25-160 Hz
  • Sensitivity: 86 dB
  • 1-year Manufacturer's Warranty

Subwoofer Wiring Guide

Wiring Guide to Wire 1 MB Quart RLP-304 Subwoofer

Mono Amp

2 Channel Amp - Bridged

Wiring Guide to Wire 2 MB Quart RLP-304 Subwoofers

Mono Amp

Mono Amp - Option 1

2 Channel Amp

2 Channel Amp - Bridged

4 Channel Amp - Bridged

Wiring Guide to Wire 3 MB Quart RLP-304 Subwoofers

Mono Amp

4 Channel Amp

Wiring Guide to Wire 4 MB Quart RLP-304 Subwoofers

Mono Amp

2 Channel Amp

2 Channel Amp - Bridged

4 Channel Amp

Specifications & Details

Subwoofer Specifications
Low Profile Reference Series
Subwoofer Size
Peak Power Handling
600 watts
RMS Power Handling
300 watts
Voice Coil(s)
Impedance (Per Voice Coil)
4 ohms
Voice Coil Material
Frequency Response
25 - 160 Hz
86 dB
Xmax (millimeters)
9 mm
Subwoofer Design
Round / Circle
Main Cone Color
Woofer Composition
Injection Molded Polypropylene - IMPP
Woofer Surround
Magnet weight
Magnet Type
Subwoofer Grille
Re-Cone Kit Available
CTA-2031 Compliant
Recommended Enclosure Specifications
Recommended Enclosure Type
Minimum Sealed Box Volume
0.5 cubic feet
Maximum Sealed Box Volume
0.75 cubic feet
Top-Mount Depth (Mounting Depth)
Cutout Diameter
Shallow Mount Installation
What is in the box?
WITB: Subwoofers
Other Accessory #1
Other Accessory #2
Other Accessory #3
Other Accessory #4
Other Accessory #5
Other Accessory #6
Warranty and Return Policy
Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider

Item Details


Model Number:




Internal SKU:


Internal Product ID:


Product and How-to Videos

  • Shallow Mount MB Quart Reference Subwoofers are your answer to BIG BASS in a tight space!
  • MB Quart Low-Profile Reference Series Subwoofers
  • Car Subwoofer Size Buying Guide | What Size of Sub Should I Get?

Customer Ratings & Reviews

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Solid Product and Great Base

I wanted a slimline sub with some kick to fit behind the seat of my Boxster. This was one of the few that would fit. It has been thumping hard ever since i installed it.

By rdttfc on January 25, 2011


found this helpful.

Shallow Mount, not shallow sound

Great driver. DVC is wired at 2 ohms, and pushing 300W to it. Made a custom box @ 0.45 cu ft. (interior volume) stuffed with polyfill per MB Quart's recommendation. For a 12 inch shallow that mounts under my passenger seat, it does a fine job on its own. Solid lows, no fatigue in sound and punchy kick drums. Bass guitars sound like bass guitars, not boomy nonsense.

Does it shake my neighbor's house? Only if I'm parked next to it, but that doesn't change the insanity inside my car's cabin that it can create without distortion/clipping. Great addition to my system.

By Boomstick on September 17, 2013


found this helpful.

MB Quart RLP 304

Great sound, excellent speakers.

By Scott on January 16, 2012


found this helpful.

MB Quart wins

This is a really great sub that fit my purpose exactly. Its an awesome unit that delivers punchy bass, has a great look yet slim enough to be easily hidden.

By Brett on April 4, 2011


found this helpful.

I love these subs!

I have an extended cab F-250. As some are probably aware, there isn't a ton of room in these trucks.

I built a box to MB Quart's spec..... and these subs do not disappoint in small sealed boxes.

By Jeff G on September 29, 2011


found this helpful.

Great space saver and gets the job done!

This subwoofer is the best if you don't have a lot space. Rich deep bass and can handle a good amount of power!

By Big Wash on July 19, 2012


found this helpful.

Good value but not the best of speakers

Having the volume air space to fit subs in my truck is a big problem. I custom built the largest sealed enclosure that I could possibly stuff under the back seat and got 0.68 cu. ft. This subwoofer's specs lined up exactly with what I needed and the price is right. I purchased the DVC 2ohm version.

Qualtiy of Construction:
I am not impressed with the materials and quality of the subwoofer but it is not terrible. There was nothing wrong with it but it just feels cheap. I suppose that is why it is so inexpensive.

The subwoofer's cone really has to be moving for much sound to be generated. The speaker must be driven hard and it really never gets as loud as it should. Perhaps that is a product of its design for small enclosures at the fact it is a shallow mount type. So, it is better than nothing, but it does not compare to a real, deep mounted 12" subwoofer in low frequency tones.

Buy again?
Maybe but probably not. There really is not another choice with the same features that I could find. I was looking for a shallow mount, DVC, 2 ohm, 12" sub that worked with a tiny box and this is pretty much the only one that I could find for a reasonable cost.

By Spike on December 31, 2009


found this helpful.

These subs bump!!

I ordered 4 of these 12in mb quarts which will be going in my 2008 dodge ram pick up. These subs bump, have them wired at 2ohms at 400watts. Surprisingly the hit lows pretty good and the high notes sound awesome. Definitely worth the money and sound better then the alpine type r's I had in my truck. FOR THE LOW PRICE YOU MIGHT AS WELL TRY THEM!

By Cody on September 24, 2013


found this helpful.

small box - big sound

This sub is designed to work in a small closed box and comes through with flying colors! I needed a small box for my boat and did not want to go smaller than 12" . I had a 3/4cuft box made for the sub. Stuffed the box with fiber and had the outside bedlinered.
Sub sounds great!

By silvrtongdvl on July 31, 2013


found this helpful.

Great Shallow mount!!

This product is GREAT. I have a SINGLE cab '87 Ford Ranger, custom built box and it fits. The box has bout .7cu ft and i have it wired at 2 ohms, pushing 550 watts to it. This subwoofer SLAMS. People are amazed by how loud it is, especially for ONE 12in SHALLOW mount. I hit the lows very easily and the highs will impress you. A very good unit to purchase!!

By J.T. on May 5, 2012


found this helpful.


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