Building a Subwoofer Enclosure




About: I am currently an Electrical Engineering student in my professional career. Currently working at a electrical manufacturing site to get my way through college. Hobbies include custom audio solutions, going o...

Designing and building your own subwoofer can be a rewarding experience. Not only will it save you money, you will also get better performance than prebuilt subwoofers, and you can make the subwoofer to what your needs are. Building a subwoofer may seem like a daunting task, but with this procedure, I will show you how easy and fun it can be. To build a subwoofer one of the skills that you need are woodworking skills. The woodworking entails building a box, bracing the inside, and staining or painting the box. Any electrical and acoustic knowledge is not required but it could be helpful. To fully construct a subwoofer it can take a couple of days to a week depending on how fancy you want to design the box and how long it takes you to cut the wood.

Step 1: Parts and Tools

Parts that are required:
Circular saw
A computer
Long wood clamps (length depends on what size you are going to build the box)
Pencil or pen (to mark measurements)

Items that are optional but are highly recommended:
Sandpaper (to smooth surfaces)
woodscrews (to ensure a good tight bond)
Drill (to screw in the woodscrews)
A large ruler (to measure wood)
A helping Hand (if you need to move heavy objects)
Access to a truck (to move boards of wood around)
Router (this is used to cut the circles that the subwoofer will be sitting it, while getting a router is optional it is very helpfull to have one to get dimensions right)

Items you need to buy:
Suboofer of your choice
Speaker wire Terminals
Speaker Wire

Optional Items you can buy:
Subwoofer box feet (optional)
Paint or stain or box carpet (optional)
Insulation (optional, what insulation does is help dampen the box, this can give clear and deep sounding bass)
Speaker grills

Step 2: Choosing a Subwoofer and Type of Box

1) Choosing a subwoofer, in my opinion is the hardest step. Mainly because there are so many choices to choose from. Here are some sites that one can check out to choose a subwoofer.

Some things to consider when choosing a subwoofer are;
-What you want the subwoofer to do
-Frequency response
Here is a site that will help with understanding these and what you want to do with them.

2) There are many types of boxes that you can make. I will only go through the more common ones, but if you are curious of what choices there are, and what benefits they have just use google.

Sealed: provides a flat response, bass sounds tight, usually can handle more power

Vented: efficient, great bass response, has complications of port noise

Passive Radiator: Has good amplification at tuning frequency like vented, no port noise, great response, more expensive

Here is a site where you can read up if you want more information

In my build I have chosen the TC Sounds PRO 5100 (older generation) with a couple of VMP18 passive radiators as shown in my pictures.

Step 3: Designing the Box With WinISD

Now design the box.
1) Go to WinISD's main site,

2) Download WinISD PRO.
3) After download is complete run executable file.
4) Follow installation steps.
5) Once installation is done run the program.

A window will show up looking like the picture above.

6) Here is a tutorial on how to use winISD PRO.

     -If you are doing this for car audio, you usually want to tune your box around 25 to 35hz depending how flat you want your        frequency response to be. In home audio and Home theater set ups you usually want to tune the box from 16 to 24hz.
Note: To keep in mind is that this is a simulation software, the final product will not fully respond to what the program simulates. In the real world you will have room gain, meaning that the room that you set the subwoofer in will cause amplification and cancellation at certain frequencies.

Step 4: Sizing the Box

1) Once you have selected all the parameters of the subwoofer that you want using winISD. Now design the box that you want the subwoofer to be in. Here is a site that will help you with calculating volumes of boxes.

     -When designing the box you will have to brace all the sides of the box. The reason why is to prevent the box from rattling and falling apart. You will have to account for the volume that the bracing will take inside the box. Another thing to account for is how much volume that the subwoofer will take inside the box.  If you have decided to put a port inside your box remember to account for volume that it will take inside the box. One option that I did was to double and triple the box's walls.(which I did because I am going to be putting a piece of plexiglass on top of the box to look inside) This makes it so you don't have to brace the box extensively. 

Step 5: Buying Everything

1) Now buy all the tools, wood, and supplies that you need to build the box and set up the subwoofer.

     -There are many varieties of wood out there to choose from, I personally like hardwood, birch, and mdf.
      Avoid thin wood because the subwoofer will cause major amounts of compression and decompression inside the box.
      Don't go with super expensive wire and other snake oil products.

Step 6: Cutting Wood

Once you have received all of your supplies now its time to get into the dirty work.
1) Lay the boards on a flat surface
2) Measure and mark the boards to the dimensions that you have previously planned when designing the box.
3) After all measurements and markings have been done move the boards to a surface where you can start cutting.
4) Start cutting where you have marked the measurements.

    -When cutting the wood and making the box, one needs to remember all safety steps. Remember to wear safety glasses, gloves,         good clothing, and other safety tips and requirements.

    -Measure twice cut once,

    -Be in an open and ventilated area, don't breath in sawdust.

Step 7: Assembly

Now its time to assemble the subwoofer.
1) Assemble the cut boards according to your design
      -Make sure that you dont miss any parts when assembling. Nothing is worse then seeing that you missed putting in a brace when the subwoofer is finished.
      -When assembling make sure that you clamp everything to ensure a good bond. You can also use wood screws to help keep a tight bond.
      -If you notice any open cracks make sure to fill it with glue or some other filling material. You want this subwoofer to be air tight otherwise you will hear high whistling from the sub when it is playing.

Step 8: Aesthetics

This step is completely up to you. This is where you take hold of your creative imagination and make this subwoofer look like a subwoofer from your dreams.

On my build, I decided to install a plexiglass sheet on the top so I can see inside the subwoofer. On the corners of the box I decided to cut 45 degree angles into the wood giving it a nice clean look. The reason why I can do this is because I didn't brace that much inside and to compensate I made the walls 1.5 and 2.25 inches thick. I also decided to stain my box and coat it in several coats of liquid glass to give it a shine.

Here are some progress pictures shown above.

Step 9: Installing Accessories

After our subwoofer aesthetics are done, now install accessories.
Accessores can include but are not limited to:
subwoofer feet
speaker terminals
speaker grills
insulation inside the box

Step 10: Move the Box

1) After the subwoofer box is completely finished move the subwoofer to the place where you are going to be leaving it.

      -The subwoofer box can be extremely heavy and awkward to carry, get some helping hands if you need to.

2) Once the box has been moved install the speakers.

      -Be careful when setting the speakers inside the box to not pinch your fingers and damage the subwoofer. Remember to wire the subwoofer before you mount it on the box.

3) Wire subwoofer to main amplifier.

Shown above are pics of where I am putting my subwoofer. 

Step 11: Conclusion

Congratulations you have finished building a subwoofer. Remember to have fun and to not annoy your neighbors from loud bass.



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    24 Discussions


    6 years ago on Step 11

    If you have a question feel free to ask and I will try to answer it.

    1 reply

    Reply 5 years ago

    buddy I already have one but I need to amplify the base and tuning sounds I need to add 2 more speakers and one bass speaker too can u help me out


    2 years ago


    The plexiglass really adds the charm.


    2 years ago

    Can you pls tell me about the wiring required inside the subwoofer cause you just breezed over it.Thankyou.


    Reply 3 years ago

    No, because the electricity is just going to one component, unless you're building a speaker with a tweeter or mid range woofer.


    4 years ago

    Which amplifier to use with 400w sub...and I want to power 2 subs.?


    4 years ago on Introduction

    i have yung sd 100 with dayton sda 270A 88 driver, i want to make small box with low response at least 25 fb, kindly advice


    5 years ago on Introduction

    Hi, thanks for the instructable!

    I'm planning on building a subwoofer capable of infrasound frequencies (I'm an artist newly interested in exploring the effects on the human body by such low freq.s as standing waves in specific environments) but unfortunately my knowledge of acoustics/subwoofers is currently pretty minimal... Do you know how I might best go about achieving this?

    I'd like to generate freq.s as low as 18hz, much lower if possible. So far my plan - based on another instructable - is to use a 21 inch woofer (Pyle-Pro PDW21250) with a 1000 watt amp and build the enclosure myself, around 106 x 106 x 30cm - or whatever is best for projecting the sound forwards. Do you think that would work? I'm also unsure about what frequency to tune the box to when working with such low frequencies.

    Any help would be greatly appreciated!

    2 replies

    Reply 5 years ago on Introduction

    Using the Pyle-Pro PDW21250 could be challenging to get what you need, but its possible. First I would suggest making the box as big as you can. Modeling the Pyle subwoofer with your current box size it would get about 105db(at 18hz and at max power) tuned to 15hz. But that would be pushing the mechanical limits of the subwoofer itself and you will probably never be able to reach that.
    Personally I would suggest a different subwoofer. When you want subsonic sounds you usually choose a speaker that has a high motor strength, low fs, and a high excursion limit.

    What type of output are you thinking you will need? If you need something above 100db I would suggest getting a different subwoofer. If you are going to be using the Pyle Pro I would suggest tuning it around 15hz, but watch out for mechanical limitations on the driver.


    Reply 5 years ago on Introduction

    Thanks for your reply, this is a great help. In light of this I think I'll probably make the enclosure 1.2 to 1.5 metres square faced and 30/35 deep... Do you think it's essential I use a 21 inch driver? If you could recommend one or point me in the right direction I would be very grateful!!! I'm on quite a tight budget and the cheapest I've found is this ( but it says its operating range is 30-200hz, which I presume means it's incapable of infrabass...


    5 years ago

    Have you ever dealt with car audio at all, particularly subwoofer boxes for car's etc. You did an awesome job on the home audio box with the foam trick making the sound larger then it is etc. If you have dealt with car sub boxes and have any tips secrets other people may not know you should download a Instructable on it, I'd be interested to see what you may come up with that myself & others haven't thought up etc. Great Instructable. Phil

    1 reply

    Reply 5 years ago on Introduction

    Car audio is relatively the same as home audio. One of the first decisions to make in car audio is how much room you want to use in your car and what box will fit in that area. Next you need to decide how much power you can send to the subwoofer. If you are running a stock alternator and battery I would stay around or below 1000Watts RMS(Note: most amplifiers that you buy are rated at peak power, this really doesn't tell you much about what the amp will really send out since that rating is usually abused and overrated) With all of the previous information you go out looking for a subwoofer that you want, if you can afford it go with good name brands like FI audio, Mach 5, DC sounds, TC sounds, RE audio...
    When you are building the box(lets say you chose a ported box since that is really common) You need to figure out what tune you want to make the box. If you got a very reputable sub and amp(spent a big chunk of change on it) and like sound quality more then loudness I would tune it around 25 to 28 hz otherwise go 30 to 38 hz(the higher you tune it the louder it will be, but you will sound really boomy and wont hit low notes very well)
    The box design is basic, just make it as strong as you possibly can without violating any acoustic laws that will distort the sound.
    This is just a very basic summary of car audio, there is a lot more into it then what I have said here. If you want you can find forums and ask questions there, or I can try to answer some here.
    Currently I sit around 140db flat to about 17hz inside my car, in a 8ft3 box tuned to 27 hz pushing about 1600wattsRMS. Personally 130db to 140db is the loudest i would go, anything above and it starts to sound the same and damages your ears faster. Currently I am fine on hearing but I am still young and RARELY blast it out. So a word of precaution, be careful with high sound levels, even though it may be fun now, its not worth the tinnitus later on in life.
    Thanks for the comment, and I may do an instructable on car audio later on, currently in college(3rd year electrical engineer) so I doubt I will have the time to do it soon....But if you have any questions I would be glad to try and answer!


    5 years ago

    Nice!! Well I gotta say it is amazing, good job.


    5 years ago

    How many hertz does the box tune the subs to?

    1 reply

    Reply 5 years ago on Introduction

    Currently I have it tuned to 18hz for home theater use. The nice thing about passive radiators is that I can change the tuning of the box by taking weight or adding weight to the passive radiators. That way when i want to listen to music for a long time i tune it to 20hz and if I really want to show off the subsonic range of my theater I go to 16hz.


    6 years ago

    this is awesome. is that needed to use that petterned thing covering inside the box? what does it do?

    1 reply

    That covering is just a bedding insulation that i had lying around. What it does is that it dampens the sound inside the box, this eliminates standing waves and essentially makes the box sound bigger then it actually is. Later on I am going to be replacing that insulation with black insulation and change the LED's to either red or blue.