Suitcase Boombox

Filled under: Miscellaneous, Projects

Date posted: September 24, 2014

After a few odd but inspiring adventures a few friends and decided to dress up in animal onesies and dance around the Virginia Tech campus on weekends. In order to blast some sweet dancing tunes we needed a decently loud system. At first I connected a LiPo battery to my 150w computer speakers but they weren’t really all that loud outdoors. Next I tried a battery powered PA speaker, again, not really that loud. So after some research I decided to build my own boombox using decently priced car stereo equipment.

During researching the options to house the equipment I ran across some pictures of boombox suitcases, pretty sweet. After a few weeks visiting the local thrift shops I found a decently sized and decently appealing pleather suitcase and began design work and construction.

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The completed boombox with one 8″ subwoofer and four 4″ woofers with integrated tweeters.

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The suitcase came a bit worn with blemishes, but for $8 I’m very happy. Although I looked for a tweed hard suit case, they were rather expensive, over $50 easy.

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Enough space inside to hold the speakers and the electronics!

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Here are all the speakers and components ready to go. The important note is that the amplifier is a class D which is more efficient than class A and B amplifiers, which is crucial for the best battery longevity. The batter is a lead acid battery that provides enough peak amps and amp hours for our needs. I could of gone with LIPO batteries but the lead acid can handle more abuse.

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Before I found the suitcase I drew up some speaker layouts to help determine the required spacial specifications of the suitcase needed.

The above shows some ideas and the beginning design with the suitcase I found. The parts were designed in AutoCAD.

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Here’s a neat shot showing some of the design process. I frequently copy the design I am working on when testing out different layouts so I can revert to the original if needed. The different color vectors are the outlines of the amplifiers and battery.

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All the parts designed and ready to be cut.

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The back plane and other parts all cut and ready to go. I decided to bring my laser engraver with me during my stay at Virginia Tech, a great decision!

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All the parts are cut and ready for assembly. Cut from 3mm Baltic birch plywood.

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Speaker holes cut.

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And now the control area marked and ready to be cut. I mounted the subwoofer to anchor the back plate to ensure the control panel is in the correct position.

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The speakers mounted and the air boxes being glued into place.

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Starting to come together!

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I noticed some sagging of the back plate into the suitcase due to the weight of the speakers and subwoofer. Luckily the suitcase has a metal bar running along it’s frame. I added a stopper bar that prevents the back plate from falling into the suit case.

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The amplifier and battery mounted and the wiring process has begun.

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At the top shows the controls wired. A few on/off switches, a volume adjuster, aux cable socket, and a volt/amp meter.

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This picture shows the shunt for the amp meter. The unit did not really need an ammeter, but I since it was cheap, I thought it would be neat to see how many amps are drawn at full blast.

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The wiring complete. The look red wire is for the secondary amplifier for the rear speakers. I decided to hold off installing them for now because I want to make sure the boom box does what I want it to before the extra time is expended.

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suitcase-boombox-speaker-system-controls

Flipping the power switch for the first time is both exciting and terrifying. So many loud pops and puffs of smoke from my childhood. Here’s the control panel. The red switch is for main power, the green switch is power to the rear speaker system, and the blue switch is the for the Aux/Lighting to be install later. The volt/amp meter works rather well and is crucial for knowing when the battery is nearly out of power.

suitcase-boombox-speaker-system-handle

I did not manage to find a retractable handle until after a few weeks of using the boombox in the field. This picture shows about 3 semesters worth of of wear and tear. The handle is black anodized aluminum and shows the scratches from pulling up the boombox over street curbs. 

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The casters are separate from the handle and are of decent quality. You can really see that we used this boombox quite a bit. The boombox weights about 40LBS and rolling the boombox versus carrying it is a day and night difference.

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Update 2016

We dragged the boombox around campus for four semesters now and let me tell you, wow, I am very happy. The volume is very loud and I run it mostly at 1/2 volume. We dance for two to three hours a session and the battery life holds up just fine. At max volume I calculated the battery life to be around one hour, but since volume and power is logarithmic and we found about 1/2 volume to be sufficient, we see greater than expected battery life.

The sound quality is not the best, but for a cheap, loud, and portable system that fits our needs the sound quality is just fine.

I did not list the parts used because I wanted to test them out for a while first and being not an audiophile, so I did not want to recommend components. Non the less, if you have questions email me.