Sound Ordnance B-8PTD

125-watt compact powered subwoofer

Item #: 777B8PTD

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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 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.

Sound Ordnance B-8PTD Reviews

Average Customer Review:

346 reviews
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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?)

I bought this subwoofer for my 89 S10 along with a new Kenwood Excelon receiver. All I can say is wow! This little speaker packs quite a punch and is a huge accomplishment to the existing speaker system. Before I had this there was just no bass in my system due to the small speaker size in the old trucks so this product made this thing sound AMAZING! Straight out of the box with factory settings it sounded incredible, quite punchy for an 8 inch. I recon as I mess with the equalizer on the receiver and play with the settings on the sub I can get it to sound even better. Installation was a breeze. I just have it resting on a rubber mat in the back of the cab. If your looking for nice low end frequencies to complete your system I 100 percent recommend this to anyone. Small, versatile, easy to hook up, and sounds amazing.

Pros: Quality, size, price, ease of installation, and sound.

Cons: Only thing I could negatively comment on is there is no bracket to mount the remote knob for the sub, it comes with an adhesive on the underside but an actual mounting bracket would be awesome. This did not hinder my overall experience with this product though.

Very happy

Written By Ron, South Carolina on Friday, December 26, 2014

Crutchfield Customer Review (What's this?)

Just installed this subwoofer in my son's 2006 Toyota Tundra along with new speakers and receiver. This subwoofer fit pretty good under the driver's seat. I am really impressed with this unit and the bass it provides. It isn't overpowering and adds the depth to the music we were looking for. I keep driving his truck just so I can listen to my music. Just need to remember to turn the volume down when I get out.

Pros: installation, sound quality, size

Cons: None at this point.

Great underseat subwoofer!

Written By QuocT, California on Tuesday, December 23, 2014

I was hesitant to purchase two of these for my car. I was very pleasantly surprised to hear and feel how well these subs worked. I installed them under the front seats of my Subaru Legacy and they provided great mid to low base that really helped bring "fullness" to my audio experience. I really liked them because they hid well, didn't take up any cargo space, and my passengers had a hard time noticing where the base came from since there was no subwoofer in back. I highly recommend these for anyone who wants compact strong subwoofers that want bass but don't have room for a 8"-10" woofer and box. I actually have an extra one for a future Mazda Miata project that I will slide under the driver seat.

Pros: Small, slim, clear bass, and built in amp.

Cons: Needs to come with some strap mounts or screw mounting tabs. The supplied velcro worked but I had an annoying time with my carpet adherence.

Sound Ordnance B-8PTD Subwofffer

Written By Roy B, Colorado on Saturday, December 20, 2014

Crutchfield Customer Review (What's this?)

Installed this in a 2001 Chev. Crew Cab for my great grandson. It fit behind the rear set on the back wall of the cab. It has a great sound and all the kids think it's great.


Written By Josh, Maryland on Wednesday, December 17, 2014

Crutchfield Customer Review (What's this?)

It works perfectly for a single cab pickup. I glued in a couple 1x4s behind the carpet on the back wall of my single cab 93 s10. I mounted it on the wall and i couldnt be happier

Awesome Little Sub

Written By Bigdogself, Winter Haven Fl on Monday, December 15, 2014

Crutchfield Customer Review (What's this?)

I installed this in my 2006 Jeep Wrangler Unlimited. Since I didn't want to loose any cargo room, I installed it in the center console where the factory subwoofer would go. This turned out to work very well, and I only lost space that I would throw small items into. This really made my system come to life. I am currently running Infinity Kappa's in the dash and overhead sound pods.

Pros: Small Size, Good Value

Cons: None

Sound Ordnance B-8PTD

Written By Cliff, Arizona on Monday, December 15, 2014

Crutchfield Customer Review (What's this?)

Wow, what an improvement for the stock radio. Love the bass, not to much, but just right.

Pros: Easy to install, found the right place behind the crew cab back seat. Great instructions and tech help over the phone.

Cons: Should have purchased one long ago. If that's a con ??

Nice sound

Written By erok, mineral, va on Monday, December 15, 2014

Crutchfield Customer Review (What's this?)

Nice sound. Gave me a nice rounded sound system. Not overwhelming bass but it gave me the thump I was missing

Pros: cost and size

Cons: none

Sound Ordnance B-8PTD

Written By Shawn, Hawaii on Thursday, December 11, 2014

Crutchfield Customer Review (What's this?)

Great sound, high quality, easy to install.

Pros: Takes up little space

Cons: None

Great to fill in the low end

Written By JoeM, Chandler, AZ on Monday, December 08, 2014

Crutchfield Customer Review (What's this?)

I purchased this to fill in the low end when doing minor upgrades to the audio system of my 2015 Forester. I kept the factory head unit, installed a set of Focal Polyglass 165VRs that I already had, an Alpine KTP-445U to power the components, and this powered sub.

The sub does great and helps fill in the low end that the component speaker setup is lacking. I am especially impressed considering it's small size and low price. I installed mine using the high level input by tapping into the front speaker wires coming from the back of the head unit harness. It fit perfectly under the driver's power seat after trimming the rear seat heater vent. I find the auto turn on using the high level input to be finicky so I ran a remote turn on lead to a switched +12V output. I removed the remote level control from it's housing and just the board fit great in a factory blank in my center console.

If you keep your expectations realistic and tune the sub correctly you will probably be happy with it. It's not going to have the sound quality or loudness of a high-end component sub in a larger box being fed by a high power amp. If you are looking for the type of bass you would experience in a club, look elsewhere. What it does do is fit in places where it is practically invisible and provide the low end that is missing in most systems without a sub. Tune it correctly and go easy on the bass boost and it will provide good, clean bass at reasonable volumes.

Pros: Small size that allows it to be installed under many seats. 0-180 degree phase adjustment to fine tune it. High level and low level inputs so it can be integrated into a system without low level outputs without needing a LOC. Easily accessible controls so it can be tuned with the car put back together. Good, clean sound at reasonable volume levels.

Cons: It is only 125W so it cannot keep up with high powered components at higher volume levels (my Focals are receiving 90W each). Auto turn on when using high level inputs is finicky. The housing and knob for the remote volume control are huge (the housing can be removed but the knob size can still limit placement in a dash or center console). Can be boomy if the gains are turned up too high and the volume is set high.