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Belva Sub Box 1SV12G (Gray)-open box

Single 12" Vented MDF Enclosure

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This item has been discontinued

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Belva Sub Box 1SV12G (Gray)-open box

Single 12" Vented MDF Enclosure


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Belva Sub Boxes are custom built to fit your application. Enclosures are made with only the highest quality materials, including 3/4” MDF, to ensure your subwoofer enclosures can handle the test of time and the thump of your new subs.

  • Single 12" Vented MDF Enclosure
  • Holds one 12" subwoofer
  • 3/4 MDF (Medium Density Fiberboard) Construction
  • Durable gray carpeting
  • Gold Terminals
  • Tuning Frequency: 36Hz
  • Internal Box Volume: 1.8 cubic ft.
  • Dimensions: 13-5/8"H x 17"D x 19-1/4"W
  • 30 Day return policy

Speaker Box / Enclosure Specifications

Subwoofer Size
Refers to the diameter of the subwoofer, measured in inches.
Subwoofer Cutout Shape
This is the shape of the enclosures cutout hole and defines the style of subwoofer that can be installed.
Round / Circle
Box Type
Represents the style of the enclosure. Be sure to purchase the appropriate enclosure type and internal volume that will be compatible with your subwoofer's recommendation.

Sealed - Sealed boxes are those that have no holes or vents in it. The only hole in a sealed box is where the subwoofer is installed. Smaller sealed boxes require more power than a larger sealed box. They provide a tight, accurate bass, while the larger sealed enclosures provide a "boomier" and louder bass.

Ported / Vented - Ported/Vented Enclosures provide an even boomier, louder bass, but less accurate then a small, sealed box. Ported enclosures typically require more airspace per sub and also less power output from an amplifier to perform correctly.

Bandpass - Bandpass enclosures make subwoofers perform efficiently, but loose. The bass is not as "boomy" as a ported enclosure nor as punchy as a sealed enclosure. Bandpass enclosures work well with lower to mid-level subwoofers.
Vented / Ported
Number of Subs/Speakers
This value represents the number of speakers or subwoofers that the enclosure accommodates.
Box Style/Shape
The box style or shape refers to the actual shape of the box. Square and rectangular boxes are straight-edged boxes on all sides, whereas hatchback and truck style enclosures feature an angled front or back design that allows for installation in places short on depth such as single cab pickup trucks. You can also use such enclosures in hatchback cars or other vehicles where space is a premium. Tube and cylinder shaped boxes were made popular by Bazooka and are a great option for those looking for a nice amount of bass without sacrificing lots of space. They may even fit in locations that slim truck boxes cannot fit in. If the enclosure is vehicle specific, we encourage you to read the product description to find out which vehicles the enclosure is made for.
Cutout Diameter or Length
The actual diameter of the hole in the subwoofer box. Length is the measured length per side of a square subwoofer or speaker opening.
Maximum Speaker Depth
Your subwoofer or speaker must not exceed this dimension in order to properly mount in this enclosure.
Total Box Volume
The internal volume measurement in cubic feet before subwoofer magnet displacement.
1.8 cubic feet
The height of the item, measured from top to bottom, in inches.
The width of the item from left to right (side-to-side) measured in inches.
The front-to-rear depth of the item, in inches. If the item is angled or slanted, this value is the bottom measurement.
Wood Thickness
The thickness of the wood the enclosure is made of, measured in inches.
Number of Terminals
The number of terminals the enclosure has. Each terminal represents 1 positive and 1 negative.
Terminal Type
Spring clip terminals work best with bare wire connections with small-gauge speaker wire, or pin-type connectors.

Binding post terminals are a sturdier, more versatile type of speaker terminal. Because binding post terminals are are threaded, you can tighten them down against the wire or connector for a tight, clean connection. The most popular style of binding post terminals is known as a "5-way binding post". This type can accept bare wire, or any of the common speaker wire connectors. Binding posts with the option to be used with banana clips are even more versatile

Spring posts are a hybrid of the two. Instead of using a thread and "screwing" them tight, they use a spring to allow the wire to fit and tighten against the terminal.

Binding posts
Box Exterior Color
The color of the enclosure's exterior/outer finish.
Box Finish
The material used on the outside of the box. Most boxes are carpeted to prevent exterior scratches; however vinyl is popular as it can often be color-matched to a near exact look of your leather factory interior.
Tuning Frequency
36 Hz

Port Details

Number of Ports
The number of ports the enclosure has.
Tuning Frequency
36 Hz

Warranty and Return Policy

Parts Warranty Duration
Not warranted
Labor Warranty Duration
Not warranted
Warranty Provider
Sonic Electronix

Summary of Customer Ratings & Reviews

Rating Distribution

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Average Attribution Rating

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High-Performance Streetwires Speaker Wire

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Banana Clip Terminals

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12 oz. Can of Adhesive Spray

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Browse 7 questions and 42 answers
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Why did you choose this?
Sonic Electronix Store
I like this box
John S on Oct 21, 2016
Closest to the 2.5 sq ft I need for the JBL S31224 sub I purchased. I plan on using some polyfill to make up the extra space.
Guilbert E on Aug 3, 2016
This item had the right cutout for my sub! Most of the stats came really close to my sub specs.
Mark W on Oct 17, 2016
I needed a 12 in box that was vented and the car audio guy in my city said a vented box from him was $135 for the box and i knew the was way over priced so i came to you guys like usual.
Gavin H on Jun 12, 2016
how do I wire this box to the sub? those brackets look flimsy and there is not much space on the bolt from the outside connector
A shopper on Aug 10, 2014
Best Answer: i agree with david's answer..if its a single voice coil just go positive on the sub to positive on the terminal inside the box ,same with negative..if its dual check on the sonic website there are specific wiring diagrams for your sub provided you bought it from can also check on you tube for different ideas.
Reply · Report · Jose C on Sep 21, 2015
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can i put a 12 inch type r in this box. it says 1.5 & this looks like a 1.8?
A shopper on Nov 30, 2015
Best Answer: Iam not sure on the R but I put a Type S in my box. Fit like a glove and sounds amazing
Reply · Report · javier g on Nov 30, 2015
· Add Answer · I Have This Question Too (0)
Will my rockfordfosgate p3 fit this? I am running a 2ohm sub to a 2ohm mono amp can I just run both signal wires to both terminals without having to use the other side as well?
Chris on Mar 2, 2016
Belva 1SV12G
Belva 1SV12G
Rockford Fosgate P3D2-12
Rockford Fosgate P3D2-12
Rockford Fosgate R500X1D
Rockford Fosgate R500X1D
Best Answer: Hi Chris,

Fitment, Yes.

- I am running a 2ohm sub to a 2ohm mono amp can I just run both signal wires to both terminals without having to use the other side as well?

The Rockford Fosgate P3D2-12 is NOT a "2ohm sub" and the R500X1D is NOT a "2ohm amp" . The subwoofer is a DUAL-2ohm subwoofer and it is very important that you make that distinction. As for the amplifier, although it is Stable to as low at 2ohms that does NOT mean we call it a '2ohm amp'. As for the second part of your question, Absolutely Not! Doing so will deem the setup improper use and will void your warranty. We suggest the P3D4-12 if you want to run that amplifier.
Reply · Report · Rick MStaff on Mar 2, 2016
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Will Kicker Comp S sub fit in this box?
A shopper on Dec 30, 2014
Best Answer: Hello ,

Assuming you are referring to either the Kicker 40CWS124/2 ; Yes.
Reply · Report · Customer SStaff on Dec 30, 2014
· Add Answer · I Have This Question Too (0)
Can the polyfill be removed?
A shopper on Jul 30, 2014
Best Answer: Yeah, it sure can. Typically the polyfill is placed in the box with a light coat of spray adhesive to keep it in place.
Reply · Report · Seth WStaff on Jul 30, 2014
· Add Answer · I Have This Question Too (0)
Is this box good for the jbl-s2-1224 on a 200 watt amp? Would the jbl-s2-1224ss be a better choice even on just 200watts? THX
Tom W on Nov 28, 2015
Belva 1SV12G
Belva 1SV12G
JBL S2-1224
JBL S2-1224
JBL S2-1224SS
JBL S2-1224SS
· Add Answer · I Have This Question Too (0)

Product Summary


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Sonic Electronix Wiring Guide

Wiring Diagram Legend

Warning: The image depicted shows the resistance change when wiring multiple subwoofer terminals. Please refer to your subwoofer's owner's manual for the proper wiring of its terminals. Sonic Electronix, Inc. is not responsible for damage caused to your audio system or vehicle due to improper installation. Please call tech support at 1-877-289-7664 if you require additional assistance.

Product Name: Belva Sub Box 1SV12G (Gray)-open box