Sound Ordnance B-8PTD

125-watt compact powered subwoofer

Item #: 777B8PTD

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352 Reviews


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Fill your vehicle with bass, not equipment

Want to put some bass to your vehicle without a lot of fuss? Sound Ordnance's B-8PTD powered subwoofer is the latest version of the B-8PT, one of our all-time best-selling compact powered subwoofers. Sound Ordnance built this new version to perform even better than its predecessor, putting a cool-running 125-watt amp and a rugged aluminum 8" sub in an extremely compact, solid ABS plastic enclosure,so you get years of bass satisfaction. This all-in-one unit frees you from having to deal with a separate sub, amp, and enclosure, saves you cargo space, and simplifies your wiring requirements. Whether it's mounted under your car seat or in an out-of-the-way location in the cab of your truck, this little workhorse will surprise you with its impressive bass and its ability to mesh perfectly with the rest of your system.

Sound Ordnance B-8PTD powered sub

This compact sub delivers strong bass without taking up much space.

Big bass from this tough little sub

A 125-watt RMS Class D amplifier powers the sub and lives on a compact circuit board mounted inside the enclosure. The sub's stiff 8" aluminum cone holds its shape even when playing hard, helping to keep the lowest notes clean, and ensuring a long life for the sub. You can adjust the low-pass filter, variable phase control, and bass boost to get the B-8PTD sounding perfect in your vehicle. Preamp- and speaker-level inputs allow convenient connection to just about any system, even a factory stereo.

Sound Ordnance B-8PTD powered subwoofer

The molded ABS enclosure houses a 125-watt amp and a tough little 8" sub.

Good design helps

The B-8PTD's tough outer casing of molded ABS plastic serves as the sub's sealed enclosure and can withstand some pretty extreme internal pressure changes with no reverberating or buzzing. Sound Ordnance conveniently located the neat, clean, easy-to-understand controls on one side, opposite all the connections, so you won't get tangled in wires as you tune your bass. The control knobs and switches aren't recessed, so you can make adjustments by hand, without the need for a tiny screwdriver.

Product Highlights:

  • powered subwoofer with heavy-duty ABS plastic enclosure
  • 8" woofer with aluminum cone
  • built-in Class D amplifier (125 watts RMS/250 watts peak)
  • frequency response: 40-200 Hz
  • variable low-pass crossover (80-200 Hz)
  • variable phase control (0-180 degrees)
  • bass boost control (0dB to +10dB)
  • preamp- and speaker-level inputs
  • auto turn-on switch
  • wired remote control included
  • 8- or 10-gauge wiring (not included) recommended
  • dimensions: 9-1/8"W x 3-1/8"H x 13-5/8"D
  • warranty: 3 years
  • Our 60-day money-back guarantee

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.

Hands-on research

What's in the box?

Download owner's manual

  • Amplified subwoofer
  • Two 15A ATO fuses (1 installed)
  • Wired remote bass control
  • 14' Remote cable (RJ-14 plug on both ends)
  • 8" Speaker input harness
  • 2 Mounting clamps (4" x 1")
  • Two 6" x 3/4" Self-adhesive "Hook" strips (half of the Hook and Loop combination)
  • Seven 3/4" self-tapping screws (to secure mounting clamps and wired remote)
  • 4 Self-adhesive foam strips (two 3/16" wide and two 1/4" wide)
  • Owner's manual
  • Mounting feet instructions
  • Warranty information

Features and Specs

Enclosure Type Sealed
Finish Material Metal/plastic
Grille Metal
Connector Type RCA/Molex
Bi-amp Inputs No
Woofer Size (inches) 8
Woofer Material Aluminum
Passive Radiator ---
Width 9-1/8"
Height 3-1/8"
Depth 13-5/8"
Second Depth N/A
Parts Warranty 3 Years
Labor Warranty 3 Years
Frequency Response 40-200
Amplifier Power (RMS) 125 watts
Maximum Wattage 250 watts
Sensitivity 88 dB
Impedance N/A
Second Voice Coil Impedance N/A
Crossover Point 80-200

Product Research



Overview: The B-8PTD amplified subwoofer features a 125-watt RMS (250-watts max) amp and an 8" sub housed in a rugged, compact enclosure designed to fit in tight spaces.

Wired Remote Control: The wired remote puts control of your subwoofer output level within easy reach. The remote can be mounted using the attached double sided tape or the included self-tapping screw. The dimensions are:

  • Width: 1-3/16"
  • Height: 1-1/4"
  • Depth: 1-7/8" (2-1/2" including the knob)

Mounting: The subwoofer, with its height just over 3", can be mounted flat under a seat in the passenger compartment of many vehicles. Two mounting clamps are included to secure the subwoofer to a flat surface.


Power Mode:

  • Auto: amp turns on when a signal is present on the speaker-level input
  • Remote: amp turns on when 12 volts is applied to the remote terminal

Level: rotary dial to set the amplifier gain control

Bass EQ: bass boost; rotary knob, 0 to 10 dB

Phase: rotary dial to set the subwoofer phase; 0° to 180°

Frequency: rotary dial to control the low pass crossover frequency; 80 to 200 Hz


Power: power, ground, and remote inputs are on a screw terminal strip; each is 0.35" wide

Line Input: stereo RCA jacks

Speaker Input: Molex jack for the included harness

Remote: 4-pin RJ-14 jack for use with included remote cable

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 verify what’s in the box, 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.

Sound Ordnance B-8PTD Reviews

Average Customer Review:

352 reviews
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Xterra Install

Written By Craig S, Erie, PA on Saturday, February 28, 2015

Crutchfield Customer Review (What's this?)

Small and perfect for underseat install.

Great addition to my factory system

Written By PCW127, Austin TX on Wednesday, February 25, 2015

Crutchfield Customer Review (What's this?)

After upgrading my 2014 Mazda3 factory speakers to Polk DB651S I needed a small subwoofer that will round out my system. I chose this subwoofer because of its small footprint and ample power. The subwoofer fits under the front seats; however I did not want to loose any foot room for the backseat passengers so I installed it behind the 2nd row seat. The subwoofer fits perfectly and takes up very little room. After tinkering with the settings I was able to obtain good bass response for variety of music. The most impressive part is the amount of bass this subwoofer is capable of handling. This is an excellent subwoofer for rock, pop, jazz, classical and even trance/ techno but not so much for hip pop. If you need a small subwoofer that rounds out your factory system then this is the one to get.

Pros: Small footprint Powerful bass Easy to install Easy to calibrate

Cons: The bass notes can be tighter


Written By B. Rossman, MA on Sunday, February 22, 2015

Crutchfield Customer Review (What's this?)

I Bought 2 of these for under my rear seat and installed 1 temporarily till I could get to installing the other.. All I got to say is WOW.. What a difference it made.. If your looking to Blow your windows or you want people to hear your Bass a Block away than this sub isn't for you.. If you want to get some clean clear bass and keep your space, than I recomend this powered subb.. I debating on even installing other one..

Pros: Price, quality, and space saving..

Cons: Can't think of any cons.... Hmmm if I come across any I'll be sure to update.


Written By VixA, Illinois on Sunday, February 15, 2015

Crutchfield Customer Review (What's this?)

I like this product so much that I bought another one, thank you Crutchfield you have a great team of people working for you that helped me pick this item and the assistance I got too hook up my system for the sound that you get out of this product it is well worth your investment again thank you.

Pros: very easy to installed.

Cons: none to be found.

Great product

Written By Anonymous, Tucson, AZ on Sunday, February 08, 2015

Crutchfield Customer Review (What's this?)

Great little bass!!! Easy hook up sounds awesome.

Pros: Great for small space!!!

Cons: None so far


Written By Jared, Moyock, NC on Monday, February 02, 2015

Crutchfield Customer Review (What's this?)

Excellent bass to match factory system.

Pros: Not over bearing

Cons: None


Written By DAN, New York on Monday, January 19, 2015

Crutchfield Customer Review (What's this?)

Great sound from a small package..Installed this in my 04 Wrangler . Fit perfectly under the seat. Not earth shattering bass but more than fills in the bottom end. For my application I don't think you could find anything better.

Pros: small enough to be hidden under the seat. great price

Cons: none for me

Fantastic addition to my Silverado

Written By teague250, Greensboro, NC on Monday, January 12, 2015

Crutchfield Customer Review (What's this?)

I called Crutchfield for advice on increasing bass in my 08 Silverado extended cab without over powering the rest of my sound. I had already installed a JVC headunit and 4 Kicker 6 1/2 inch door speakers. Will, from Crutchfield, recommended this SO subwoofer. He nailed it!! Couldn't be more pleased!! I'm "fairly" handy and install was simple and took about an hour. Installed under the center of the rear seat firing upwards. Does exactly what I wanted, added good, clean bass. Like other folks have said, if you want quality listening music, this will work great. If your out to shake the neighbors......look another direction.

Pros: Great improvement to bass, simple install, and reasonable pricepoint

Cons: None at this time

Love my purchase

Written By ChucksB, Florida on Sunday, January 11, 2015

Crutchfield Customer Review (What's this?)

I am very pleased with my purchase of this sub. You wont be able to start a block party from your trunk but this sub sounds great. I installed sub under the rear seat of my 2009 tundra. The sub does a great job filling the cabin with low end sound.

Pros: great price, very easy to install and good sound for tight spaces.

Cons: none

Sound Ordnance

Written By fsum242, Florida on Sunday, January 04, 2015

Crutchfield Customer Review (What's this?)

I ordered this thinking it would fill the lows not expecting any real bass. I kind of does but I wouldn't ever buy again. Just spend a few more $$$ and get what is needed. It only lasted 2 1/2 year before it crapped out b/c you have to turn it up at least 3/4 of the way to get anything noticeable - Crutchfield honored the warranty but no new warranty on the new one as it is still under the previous 3 yr warranty so it comes with a 6 month warranty. The new sub has a D class amp which I do not believe is even as decent as the last one but I am thankful to Crutchfield for a quality warranty but the sub is by far, below good level quality. I'll be selling it soon as I will upgrade.

Pros: compact

Cons: no real bass - just a filler

Bad Luck!

Written By Unit will not fit, Arizona on Saturday, January 03, 2015

Crutchfield Customer Review (What's this?)

Was really looking forward to adding this unit to our CR-V. The original sub was way too small and didn't deliver a solid low end. This unit is just a shade too tall and a hair too long with the wire lugs touching the seat structure. Not a problem for the gang at Crutchfield! I returned it and ordered upgraded door speakers that will widen the range and compensate for the factory sub, which I didn't reinstall. I have some room under the passenger seat for a future upgrade.

Sound Ordnance B-8PTD

Written By Anonymous, Kentucky on Friday, January 02, 2015

Crutchfield Customer Review (What's this?)

For its size it works for my purposes just fine. Setting the gain took a bit, but all in all, I like it

Great for small cars

Written By Troy, Redlands, CA on Friday, January 02, 2015

Crutchfield Customer Review (What's this?)

I bought this for my wife's small car. I can not believe the sound this little box has. It is a great value for the sub and the amp built in. I read some critical reviews on this but I was looking for something to fit inside of a small car that would be less work then hooking up a complete amp and sub system. This fit the bill and surpassed my expectations if this little box. I highly recommend this for anyone on a budget or someone whom does not want to take a long time to install a sub. I think this box works best in small spaces, such as small cars to regular cab trucks. Anything with a large volume of air space where the sub will be place should be installed with a bigger box a proper amp. But for my job this was perfect. I had reservations when I saw how small it is but it packs a big punch for its size.

Pros: Good value, easy installation. Big sound for a little box.

Cons: none yet


Written By Gil H, Lincoln,Ca. on Wednesday, December 31, 2014

Crutchfield Customer Review (What's this?)

I have looked at all options of tuning this 8" woofer and nothing has panned out. If you listen to your music semi low and adjust the bass all the way up you can begin to even out the sound yet the boom becomes thunderous and you can no longer hear the strum of a deep guitar string or a tight hit when the time calls. I am sending it back and trading it for a RockF 10" or 12" with an amp for the same price. I'll build a small sealed box and find what I was looking for.

Pros: Crutchfield is the only place to shop for hastle free great deals and astounding service.

Cons: This box is built great but doesn't hold the key to fine tunes.

Sound Ordnance B-8PTD review

Written By Alan, Sonoma County, CA on Tuesday, December 30, 2014

Crutchfield Customer Review (What's this?)

EAZsy and small but sounds large! Love it. Adds a thump to my Sienna's ride to town.

Pros: small and easy to install.

Cons: None:)

Not really a subwoofer

Written By nustada, Washington on Monday, December 29, 2014

Crutchfield Customer Review (What's this?)

This is more like a mid bass with poor range. This has a lower end frequency of 80hz. Most good speakers hit that easily. I ordered this mainly because I am short on room and was going to stick it under the passenger side seat. But even for that purpose, it does not help much my speakers overpower, and it fails to bring out low frequencies.

Crutchfield response on Tuesday, December 30, 2014 We forwarded this review to our Technical Support team for follow-up. Lifetime tech support comes with every Crutchfield purchase.


Written By Eric, Maryland on Saturday, December 27, 2014

Crutchfield Customer Review (What's this?)