Build a Portable Audio System! (Powerful!)





Introduction: Build a Portable Audio System! (Powerful!)

About: I enjoy building, modifying, and hacking anything! I have been building stuff with the help of my Dad and friends since I could pick up a screwdriver. I have knowledge in electronics, programming, woodworkin...

Looking for a powerful audio system to blast at a party?
Want high fidelity?


Easy to build and affordable?
This project is for you!

Thanks too billbob and his tutorial which helped me get the basics down for this project

billbob's project!

Step 1: What Is Required....

You could essentially get by without half of these parts and tools, but it could be done with many other tools and materials so no worries if you are missing a number of the parts and tools! This is just what I used.....

You will need basic electronic skills, moderate woodworking skills and access to tools, as well as some patience. My project total came out to $150 but it could be more or less depending on when you hit the sales and what parts you use. I am lucky and my Dad let me borrow a whole lot of his tools but you may need to improvise and borrow friends tools or hope that home depot or Menards or wherever you bought your wood will cut the pieces down to the size you need. Here are most of the tools recommended. (You could get by with half of these tools if you have too).
1. hand saw or table saw
2. power drill or dremel (something to make small holes with)
3. soldering iron
4. table you don't care about
5. paint brush
6. jig saw (something to create the large 8" or so holes)
7. vacuum cleaner
8. basic screw driver
9. heavy duty scissors

10. staple gun or nails.

parts required

  1. woofer
  2. tweeter
  3. crossover
  4. mdf
  5. screws
  6. glue
  7. amplifier
  8. power supply 12v
  9. wire
  10. heat shrink tubing
  11. electrical tape
  12. port
  13. cord for psu
  14. caulking
  15. paint
  16. staples for staple gun

Step 2: Find Your Drivers.

First thing to figure out is what drivers you use. I chose "Goldwood GW-8PC-4 8" Heavy Duty Woofer 4 Ohm" from
It only requires 0.85 ft.³ cabinet tuned to 44hz, which is nice. It produces excellent bass for the cabinet size and woofer size.

Lanzar - OPTIBT38 - Optidrive 400 Watt Heavy Duty Die Cast Aluminum Bullet Super Tweeter from Very powerful and highly efficient. I chose this crossover because it is very high quality and on sale at the time of writing. I chose a Lanzer car amplifier because it is powerful (200 watt rms) and small

"Lanzar HTG237 Heritage 1000 Watt 2-Channel Amplifier" from Lanzar HTG237 Heritage 1000 Watt 2-Channel Amplifier you can find this amplifier on $71 or you can find it on amazon for only $55 but you will have to pay for shipping on parts express items because it does not come out to the $100 free shipping mark. So either way it costs the same. I chose 10ga wire because low gauge wire is overrated when it comes to making short connections. I used a 2" port but given that you are probably not building this project the exact same as mine, I won't provide the details here (find all the details to my project at the end of the tutorial).

HP DPS 600PB This is for powering the amplifier. The car amplifier will require a power supply providing 12v. I chose a server power supply because they are very cheap to buy used on ebay (got mine for $15) and very reliable (they power servers) They provide plenty of power and very stable voltage with even smaller ripple.

Step 3: Cabinet Sizing

Once you have figured out which drivers you want to use, look up their space requirements. If you get your drivers from it normally tells you. If not, do a quick google search on it. My particular size is 0.85 ft.³. I am porting my speakers for more bass volume. The box is tuned to 44hz.

Also, some drivers sound better without porting. Once you have figured out what size cabinet you need, figure out the dimensions of the cabinet. Remember to include the width of the wood. Here is a handy calculator for figuring it out.

I used this calculator for figuring out port length.

Step 4: Cutting Out Wood Pieces

Sooooo now that we have reached step # you are well on your way. I spent a whole month searching around for what would meet my needs (mostly looking for sales because I am cheap). Find (or buy :p )either 1/2 or 3/4" mdf. I found a 3/4" from a construction site that was discarded. It had cuts in it but I filled those in with wood filler. If you used the calculator I provided a link to in the previous step you can adjust the dimensions of the box until you like it. Then, mark out and cut your pieces. Remember to mark only what you are about to cut so that you don't have to include the thickness of the saw blade. ex. mark a 12" x 16" area out on the edge of the wood. Cut it, then mark out the next piece and cut it. Make sure to make all sides parallel to each other or you will have a ton of sanding and filling to do later. Then, measure out and draw the circles for the speaker holes. Double check, then drill a pilot hole larger than the blade on the jig saw. Cut around the markings and test fit your speakers. I didn't countersink the edge because it is a very small edge and barely noticed.

Step 5: Glueing Box Together

Now that you have your pieces ready to be glued and screwed; put one edge flush against a wood vice and put the corresponding piece to a right angle on the edge of the other piece. Put wood glue where the wood meets to help make the box more air-tight and stronger. Then clamp everything in place. drill pilot holes and countersink the screws so that they will be flush against the surface, if not a little bit under the surface. Do the same for all the sides that can be put in the vice. I did not use a vice to screw the pieces together, but now I wish I did as it is much easier to keep everything at 90 degrees. You may add bracing inside the box but I chose not to, and it is plenty strong. DO NOT GLUE THE BACK PANEL ON! If you do you will have a very hard time removing it once it has dried. Do drill holes for screws but don't screw the back on. The back will go on at the very end. You may add handles, but that adds complexities I did not feel like dealing with it and doesn't look nice aesthetically.

Step 6: Filling in and Priming.

This is when I realized I wanted to create a tutorial for others so I started taking more pictures :) Once your box has been constructed and dried, it is time to fill and sand the gaps. Once you have filled in any cracks and covered over the screw holes, it is time to prime it. I used a can of primer spray paint and put a light coat on. Then I sanded it down with 400 grit paper and used a damp paper towel and removed any paint particles. It is important to do that every time you sand down anything to do that from now on. Repeat the priming process, sand, prime again, and use a fine grit sandpaper on the final coat. Wipe off really well and let the water dry. Don't wipe the water off with a paper towel as the fibers in it may stick to the box if you care.

Step 7: Painting Time :)

Now we are going to add some actual color to it. Whatever your paint pattern is, make sure that you use oil based paint for a very durable finish. I really wanted to use acrylic based paint, but now I am glad I used oil because it will survive for a long time. I chose a black on yellow squares, but it is much easier and faster to paint everything one solid color. If you are doing squares, paint yellow in the general area that is going to be yellow. It is way better to go too far over than to not put enough as you can just sand down the extra paint later. Paint one surface, then let it dry for an hour or so. Then, very carefully so as not to touch the semi-wet paint, rotate the box to its upright position. Paint the top and let it sit for another hour or so. Then put down wood blocks or something so that the wet paint doesn't touch the surface of whatever it is sitting on. Here is a little trick: any surface that is parallel to the other side can just be flipped over 180 degrees and set down even though it has not sat a while because surface tension and gravity will make sure the paint doesn't drip or be uneven. Saves time and rinsing out paint brush a whole lot. I wipe my paint brush off on the inside of the box to remove the extra paint once I have finished painting for that time.

Step 8: Back Panel.

While the paint is drying, you can work on the back panel. I spray painted the back panel red. Figure out how you are going to position everything like amp, psu, hole for wires to come through, and control box. Drill pilot holes for everything. I used a coffee tin for the control box. I soldered a switch and 1/4" jack and 3.5 mm jack for the box. I drilled a hole for each component. Make sure to back the metal tin with something like wood so it does not rip the metal instead of making a clean hole. You can see a hole that I made the wrong size in the picture. I fixed it by adding a foam cover so that you cannot see it error. Screw the box in. Go at an angle so that you can hold it in more securely. ( mean so that you can attach screws farther in the box than if you went in at a shallow angle). Attach the amplifier and make sure that the sense wire (connected to the switch we added earlier so that you can turn it on and off) I permanently attached the connection because I wanted to turn off the power hungry psu, not the amp. Drill a 1/2" hole for the wires to pass through.

Step 9: Lacquer Finish

Once you have painted you box, you may want to put a lacquer finish on it. I sanded my box down to a very smooth finish and then applied a high gloss spray finish to it. It looks really nice now and is even more durable. You just want to make sure you put a lot of light coats on instead of 3 heavy coats. It dries very fast so there is no reason to rush it. I put a slightly to heavy coat on one side and had to sand it down and re-coat it.

Step 10: Add Carpet Material.

Once your lacquer has dried for 24 hours, (12 if you use fast drying type) you can add carpet material or something to stop the sound from bouncing around a lot. I found old carpet material from when our house was being constructed. You may be able to find some from a dumpster or somewhere. I don't recommend taking it from your living room floor XD. Use a staple gun or hammer and nails to hold it down. Remember to cut the carpet smaller than necessary.

Step 11: Now That You Have Reached Step 11......

Well you work desk probably looks like this...... Measure the length of wires you need and then solder them to your crossover unit if required. Some speakers require that you sold the wires to it instead of being clamped in. Solder those wires now (not to the crossover unit) because it will be hard to do that once they are mounted in the box.

Attach the speakers, however they attach. Usually speakers come with mounting screws like mine did. Then measure your port to the proper length using this calculator....

and then cut it with a saw and remove the burrs with a knife, file, or something other than your teeth. I sealed around my speakers with some rubber double sided tape, but that was because they didn't make a nice, tight seal against the side due to the hole that I cut being too small.

Step 12: The Power Supply Modification

The amplifier requires 12v at around 20 amps. Unless you are only running this box off of your cars for tailgates and such, you will want to mod a power supply (very cheap, fairly easy) or buy (expensive and hard to mount). We will be using a HP DPS 600PB server power supply bought from ebay for $18. In comparison, a prebuilt one will cost about $70. You will also need to buy a power cord from Amazon or somewhere. Look at photos to see what I am doing in the below steps.

1. Remove the cover on the PSU to remove the lever on it. There are several philips head screws to remove. Try to only remove only the screws that you need too.
2. Use a drill bit about twice the size of the holes holding it in. Drill until it hits the shiny metal of the lever. Pry up the lever with a flat head. You might be able to just pry it off without drilling it, but you risk bending the cover.
3. Put the panel back on.
4. Use a flat head screwdriver and pry off the handle.
5. Find the small pins on the PSU. Orient the PSU with the fan on top of the pins.
6. Solder pin 8 to ground (see pictures). Solder pin 8 to pin 4. This will prevent PSU from sounding like a jet.
7. pins 6 and 10 connect to the power switch wires.
8. Tin the positive and negative leads.
9. Use 10 ga wire black wire and strip the last 1/2". Divide the wire strands into two groups. Twist the two different groups of wires. Tin the two sets of wires. Put the wires into the negative slot and solder in place. Slide heat shrink tubes over wires and apply heat.
10. Do the same for the positive (red) wires.
11. Test the PSU by switching the switch :P If it doesn't turn on, make sure you shorted pin 8 to ground (negative).
12. wrap electrical tape around all the wires so they are not exposed.

Step 13: Put Everything Together.

Attach the amplifier and switch box if you have not already done so. Since the PSU doesn't have any mounting holes for attaching to the back panel, we will create mounting holes in the back wood panel. As the pictures show, the PSU is held in place with zip-ties. The zip-ties are held in place by holes drilled in the wood just wider than the zip-tie. I drilled a 1/4" hole marked halfway between the 3/4" wood panel. I drilled it about 1/2" deeper than the psu is wide. Then I measured the length of the hole by putting a thin screw driver down the hole, putting tape where the driver sat when it reached the bottom, and measured how long it is. I then figured out where the hole's end is by measuring that distance out on the wood.

Then drill a corresponding hole down until you hit the sideways hole you just drilled. Remove all the sawdust and wood shavings from the hole. Thread a zip-tie through the hole you drilled just a second ago. It will not go in the other way (through the side of the wood) because the zip-tie has to bend to get around the corner. add another zip-tie to the other zip-tie because only one would not be long enough to wrap around the PSU.

There are other ways of attaching the PSU, that is the only way I had that did not require going to the store and buy a bracket or something else. Plus the zip ties hold it in very well! Put the PSU on the back panel with the power plug facing upwards; but not so far that you cannot remove the power plug in the future and that the wires on the bottom that you soldered on don't touch the ground. See pictures. Once the PSU is in it's final place, hammer a nail be the bottom of the back panel so that the PSU does not slide down. Bend the nail so that it is holding the PSU in place with some plyers.

Step 14: Wire Up the Amp

Attach the wires to the amp. I bridged my amplifier as you can see in the pics. The signal wire is always connected to 12V so it is always on when the PSU is turned on. Don't do this if it is powered from your car or other external 12v source. Parts-Express kindly included a small screw driver in my order so I attached in the the box so that I can adjust the gain and bass boost. I already had a cord for connecting into an ipod and I made a 50 foot cord from some wire I found that I don't use because it is too heavy duty for most projects.. If you don't, you can make one in the spirit of Instructables and makers or you can go buy one from the store or find one.

Step 15: Mount the Back Panel and Attach Feet.

If you want really nice sound quality, I recommend adding 1/8" tube foam insulation hot-glued to the box around the edges. That way it makes a nice air-tight seal when you attach it. You may have to add extra screws so that the back panel does not warp when you tighten the screws down. I think it would be fine if you skipped this step, I don't think there would be much of a difference noticed.

I also added feet to the bottom to keep it from sitting on the ground. I found them at Menards for $1.50. This also helps in case the box doesn't sit completely level.

Step 16: Test It!

Turn the gain on your amp all the way down. Check all your connections for shorts and plug it in. The fan should be barely audible. Flip the on switch and the amplifiers light should come on. plug in some music and turn up the gain till you can hear it well. I could not test what my proper gain should be before it starts to max out as everyone in the house would probably be deaf at worst, and at best, not happy with me. If it works, congrats! You built a very powerful system if you followed all my steps correctly. It it doesn't work, test with a multimeter if there is 12V coming out of the PSU. If there is, test the amplifier. If the green light comes on then there could be a problem with the speaker wiring. If the red light comes on, you definitely wired it incorrectly and need to check your connections starting from the speaker output. I will be posting a video soon on my project and would really like to read your opinion and if you built it, I would love to see pictures of your project!



    • Creative Misuse Contest

      Creative Misuse Contest
    • Water Contest

      Water Contest
    • Oil Contest

      Oil Contest

    20 Discussions

    I enjoyed reading your Instructable! Clever trick running the amp bridged to your x-over for a mono signal. Don't worry about the wattage because it's nice to have a little headroom so the amp doesn't strain, and the advertised wattage is probably for peak wattage running at 16V. My only concern is there may be a mid-range frequency gap between the woofer and tweeter exaggerated by the ported enclosure tuned at 44Hz. The only way to know for sure is to listen to the same song on another stereo and listen to the difference. I discovered that mistake with my first car stereo when listening to the same collection of songs on my parents Sansui Quadraphonic stereo (some things from the 70's were cool). I started hearing instruments and voices that I hadn't heard before. If that's the case, an easy fix would be to pair a full-range or coax speaker with your woofer. Don't sweat it if you like the sound as is.

    6 replies

    Thanks! Glad I picked the right amplifier! I could buy another port (it's cheap $2.00) and then tune it to a different frequency. I did that because thats what the goldwood recommendation was. I will listen in comparison to our home theater system to see if there is any difference. I picked the 8" instead of the 10" for that exact reason. I was afraid the 10" goldwood would have a large down spike in the 2500 hz section after looking at the frequency response chart. What do you think? Thanks, Squidyman

    Your're right and the 8" will not hit as deep as the 10", but I don't think either will extend up into the mid-range area. Maybe if they were full-range speakers. I built a system with a ported 8" in my truck that is compliented with full-range coax speakers, so the 8" just fills in the bottom-end. Either way, just compare same songs on different speakers to hear if there is any difference. You're still making music and don't sweat it if you're happy with the results. Honestly, this is a nice build and I wish I started at your age with the skills you have represented here.

    Thanks! I have almost no speaker fuzz at all because I have my gain turned all the way down. I might have been better off with a 6" mid-woofer and a 12" sub but that would blow my budget and be way too large. Same with using a mid range. I decided that I would have to compromise so I went for the 8" Would I have been better off getting the 10"? I am happy with how it turned out, just curious to what someone with more experiance would have done.

    You've got to be carefull with headroom still, to much and you can easily blow your speakers or psu.

    Agreed, blowing speakers is a potential hazard but over-driving an amp into distortion can blow speakers too. For this situation (a lot of power) just set the amp's gain at a level where the speakers can take the power but are a little shy of distorting. Then you don't have to worry about someone else cranking the volume and blowing speakers.

    Hope that helps.

    Yes, I will definitely not blow my PSU (rated at 600 watts), but I am still not sure about my speaker.......

    'could> couldn't'

    I could see your raspberry comment on the site. I might make I'tbl but progress wil probably be slow, I have a bussy schedule coming up so don't expect it anytime soon. Living room will be wired, the all in one might get wifi or maybe I'll extend my powerline.

    weird...on the site not al reactions are visible... if your 12v powerline exceeds the fuse demand of your psu you should be good. The raspberry is going to replace an old popcorn a-100, and I'm going to see if I can build an all in one media centre with it using an old 19" flatscreen monitor.

    1 reply

    what do you mean by "on the site not al reactions are visible"? Is there a problem? I am re-writing the opening statement to be more attractive.

    Cool! Will you be posing a instructable on how to build that?

    And a note on the Rasb. Don't buy that really cheap wifi adapter.... no range at all. Buy one with a nice, long antenna.

    Got a feeling your amp is way to big...those watts from your speakers are max watts and are rarely reached. Look on youtube at some of those coolerbox soundboxes, you will see they often have a small amp. I myself build a small case with a 4x100W carradio and 2 300watt 3-way speakers and thats more than just loud. Those speakers can't get more than a 1/3 of their max watts but are stil loud. Splitting it up will suffice, timeline is diverend for everybody due to work etc.

    3 replies

    What do you mean by "splitting it up"?
    I agree that the amp is too large. I would need a filter to pass the low frequencies to a subwoofer because the woofer would distort any bass at such high power. That would cost another $80 that I don't really need to spend. What amp do you recommend that is around the RMS of the woofer (165 watts) and can be bridged or is mono?

    splitting it up: your time on the separate parts.

    Id's say google is your best friend, do some research figuring it out and add it to your I'ble. Learn us a thing or to, I'm not a audio expert so i would need to do my research too and having a car needing a MOT and a raspberry Pi on its can do.

    It's surprising how much you can do if you do your research and set your mind to it.

    I would add a fuse in the powerline to your amp to protect your PSU btw.

    Okay, will do. I spent an entire month on researching parts before buying (for instance deciding between the 8" and 10" woofer) I can give recommendations on compatible speakers and other parts so they can differ from what I did for more flexiblity. Funny, I am incorporating a Raspberry pi into my design now as well for wireless playback!

    true paint and finishes take time, then again you don't watch how it dry's. I'd split it up in sections and wait time. So time for building the box, wiring it up and paint & finish. Also makes it easier for others to adapt for their abilities and changes to your design.

    1 reply

    Will do! I will also add a time line so it is more easily understandable. I also may clarify some details I left out like figuring out how to pick your drivers and amplifier if they don't choose the ones I used. It might be useful I think. What do you think?

    not in a weekend ok....but 2 whole weeks? Than you're just being lazy. I'd say a weekend for the box and preping your wiring and another for finishing it up. It al depends on the experience you have. Nice box and clear instructable anyways!

    2 replies

    I changed it to a week. Does that sound better? :)

    No, you have to let the paint dry for at least a day before it can be sanded. There are 4 sides that cannot all be painted at the same time. Say if you only did one solid color and used acrylics it could be completed in a couple days. And my PSU got lost in the mail so that didn't help. Maybe I'll change it for the "average" person :) Thanks for the kudos!