free shipping at parts express

Home Subwoofer Project: The K-12

Project Category


Speaker Projects


Tactile Transducer Projects


Home Subwoofer Projects


Home Audio Projects


Amplifier Projects


Car Audio Projects


Other Projects


  Add Your Project

Create projects with your own descriptions, photos, design goals, material selection, schematics, and share with other audio enthusiasts.



Shop Parts Express

Ready-to-Assemble Speaker Kits

Speaker Building Components

Find the Right Woofer

The K-12

This sub woofer project was an attempt to make the absolute most of my old 150 watt JBL SUB-10 plate amp, and also to create the ultimate college dorm sub (which it was, and then some!)

The K-12

Designer: Scootch

Project Time8-20 hours
Project Complexityhobbyist
Project Cost$100-$500

Driver Selection

this sub has a total of five woofers in it: one 12 inch Kicker 2010 series comp, which is the powered driver, and four 8 inch Dayton Audio passive radiators. I was told repeatedly when i purchased the Kicker that it was a bad idea to use a car sub in home. For this driver however, I think it works better in home than in car. For a car sub, it has very high efficiency as well as extension and fidelity.

Enclosure Design

the enclosure itself was out of a vintage 10 inch 2-way speaker for which I accidentally blew the woofer to, so I decided to build a sub out of it. the dimensions are approximately (W,H,D) 14.5in, 25in, and 11.75in respectively. the enclosure has 3/4inch MDF on all sides except the front baffle where it is 1.5in thick. It is approximately 1.5 net cu. ft. internal volume, which is ideal for the Kicker in a sealed box.

Amplifier/Crossover Configuration

the amp's low pass filter in my system is set around 80 Hz or so, but this sub could be easily blended with most speakers, regardless of where the crossover is set.

Enclosure Assembly

This was (in my case) fairly easy as all I really had to do was reinforce the front of the enclosure, cut out all the holes for the amp, the Kicker, and the four passive radiators. The Kicker sits in the exact center of the front face while on the left and right sides, the passive radiators are centered 5 inches below the top and 5.5 inches behind the front baffle of the enclosure (for the top right and top left PRs). The lower two are centered 5 inches from the bottom and 5.5 inches from the front. It received a semi gloss black coat of paint on the front baffle and gold on the sides. There is also damping stuffing all inside the enclosure. The tune on the system is right around 30Hz or so with about 300 grams of weight added on each PR (total of 375 grams).


The result was astonishing to say the least. It is the best 150 watt sub i have ever heard by far. It rattled stuff over 100 feet away in my old dorms and even woke up my friend ten doors down the hall! It weighs in at around 65-70lbs, yet takes up just a little more than a square foot of floorspace. The K-12 hits triple digit dBs from 100Hz all the way down into the mid 20s with ease. At full power (in a large room) it will max out at around 110dB and wherever the room resonance is, it'll be more around 116 to 118dB! The K-12 also manages useable extension below 25Hz, as well as fantastic sound quality. output is almost perfectly linear from 110Hz down to around 28-27Hz. The sound isn't muddy or boomy at all. It's easily comparable to the Velodyne DLS-R 12 inch my uncle has in his home theater, and that costs at least double what this cost me. I have gotten nothing but complements from friends, but nothing but complaints from everyone else outside my room (guess why!)

About The Designer

I love speakers, especially sub woofers. I have had four audio systems over the last eleven years, three of them with subs. Ever since age 13 I have looked for ways to make the most of my old 10 inch JBL whether it be stuffing the old enclosure to drop the tuning frequency or by using passive radiators to increase the sound quality. When the ten inch in the original sub finally let go, I decided to build a new sub. I am now 19 and a Sophomore at CSU Chico still trying to modify the K-12 to squeeze out as much as that old amp can crank out, and thankfully, I finally can't.

Project Parts List

Dayton Audio SD215-PR 8" Passive Radiator


Start a discussion about the The K-12 project.


Next > Unique Parquet Subwoofer Table

Next > Unique Parquet Subwoofer Table




Parts Express FacebookParts Express TwitterParts Express YouTubeParts Express PinterestParts Express SpotifyParts Express Instagram
Live Chat Software