How to Build a Stereo Cooler
I love to tube the river in the summer, but what’s a hot Texas day, beautiful countryside, and cold beer without good music? It’s possible to buy floating or waterproof radios, most of which double as coolers, but I have never found one that actually generates serious volume. Worse, central Texas rivers are often in deep canyons, with little or no radio reception. I had seen people on the river with what appeared to be standard chest coolers that had been custom fitted for audio, but I couldn’t find anyone online that made them or even any information about how to do it. So, I embarked on a project to make my own Stereo Cooler, and what follows may be the first Internet Guide on how to build one. As a standard disclaimer, if you try to modify a cooler using this information, you agree that I’m not responsible for any injury – use at your own risk! [Edit: Note also that contrary to what some links into this article suggets, this is not a free-floating cooler; you need to put it in a tube to take it on the river]
Things you will need:
- A medium to large size cooler with (very important) a latch on the lid – $30 from Walmart or Academy Sports
- Amplifier installation kit 8 or 10 gauge – $35 from Best Buy, or $20 online
- Waterproof Marine Speakers – $60 online
- 2 channel car amplifier – $50 for 400W Jensen online
- Medium sized 12 volt battery, e.g. for a riding mower – $20 at Home Depot (try to get a sealed one)
- Ratchet tie downs for roof rack – I bought Good Year Tie Downs at Sam’s Club for $20, but probably any kind will do
- RCA to headphone adaptor or cable – You can buy these at Radio Shack or Best Buy; they cost a couple of bucks and look like this
- An electric switch – $3 from Radio Shack or Fry’s, don’t worry overly about A/C vs. DC or the voltage, it’s for a signal line only
- Tools: Exacto knife or box cutter, wire stripper, screwdrivers, pliers, hack saw blade
Note that I built my cooler to support an iPod, so I bought an Otterbox Waterproof Case at Amazon for $40, but you might decide to go without this added protection. Total cost, assuming you already have tools is $200.
First, you need to set up your amplifier. There are a variety of marine amplifiers available, but they’re build to withstand salty air and are not really waterproof. I opted to go for a cheap car amplifier so that if it’s lost in the river it can be replaced cheaply. I’m not an expert on audio, but at the low end of audio you don’t really need to think overly hard about matching speakers omhs with amplifiers, etc. Audiophiles might look down their noses at the Jensen and Clarions I used, but they’re solid, cheap, and do the job. Believe me, they are a LOT louder than they appear for their size and price.
You can see the amp hookups below. +12V goes to the battery positive terminal, GND goes to negative. REM stands for REMote terminal, and typically connects to the “head unit” in your car that has the radio, CD player, controls etc. I chose not to use a head unit for this first project to keep things simple, but we need to be able to turn the amp on and off, so the way to do this is to connect the REM to +12V with a switch inbetween. My amplifier installation kit came with a thin REM wire, and the switch I bought has three settings, and I connected the REM wire to the middle position. This means that the amp is on when the switch is in the middle, but off when to either side, meaning that you don’t have to see the lights on the amp itself to know if it’s on or off. The skirt around the switch is just some heat shrink plastic, it’s probably optional. Note that you can click on the images to see more detail.
Once you have the amplifier hooked up and calibrated (read the amplifier instructions for this), it’s time to start cutting up the cooler. Conveniently, a CD works as a template. Draw the template and cut using a box cutter. It’s very important to not cut the holes too large, they don’t need to be very big we can adjust them later.
Scraping out the foam insulation is messy, so have a dust buster handy. Once you have it scraped clean, cut the inside holes. These can be smaller, and rougher since they won’t be seen. I finished it with sand paper for a smoother look.
Check the speakers for fit, and use a knife or pen to mark the cooler surface where the screw holes on the speakers line up.
The speakers should come with panel clips that will help to securely clamp the speakers to the thin surface of the cooler. Use the clips as a template to cut out rectangular notches large enough so that the hole in the clip lines up with the marks you made on the cooler.
Now you can fit the speakers and secure with the screws provided. The Clarion speakers I purchased have a sticky, waterproof seal on the back, but you could put caulk around the edges for additional water protection if necessary.
Now we turn to the guts of the stereo and the power supply. It’s very important that everything inside the cooler be secured, especially the battery which is very heavy. If the cooler tips over in the water, a loose battery would break the latch and rip everything out of the cooler, and even if the cooler stayed closed it would probably damage the other contents – don’t take a chance on this. I thought about a variety of ways to secure the battery, then came up with the idea of strapping it to the wall of the cooler using a ratchet. This way, it will be tight but can also be removed easily for recharging or replacement. Ratchet tie downs usually come in two pieces with hooks, so we’ll need to modify it into a single loop.
Cut the strap completely off the ratchet, cut off the hook from the other strap, and cut it down to a length that can wrap around the battery and still leave 10 or 12 inches.
Now we have to fix the strap to the ratchet, I used my wifes machine to sew it together, but you could probably use a strong glue or staples if you don’t have a machine.
Cut two narrow slots in the side of the cooler, one above the other, and use a hacksaw blade or something similar to push the strap from the top to the bottom, making sure that the ratchet will be facing the right way up.
Pull it through the bottom slot with pliers, this is much easier than I thought it would be. Apply duct tape around the edges of the slots so that the thin wall of the cooler doesn’t tear.
Now position the battery and strap it in. If you’ve positioned the slots correctly, you shouldn’t have to worry about overtightening. This battery is going nowhere!
That’s the hard part done, now all we need to do it screw down the amplifier into the bottom of your cooler, or onto the side if you have a smaller cooler, and we’re pretty much done. Attach the amplifier switch to the side of the cooler using screws or strong tape and use plastic ties to tidy up the various cables.
The finished cooler. Maybe if I was doing it again I would get a different colored cooler or speaker covers to stand out a little, but its innocuous look belies the power that is inside. With the 400W Jensen and Clarions, the volume easily went so high as to be uncomfortable to the ears! I also found that the system had plenty of bass. It probably would be effective to use a 4-channel amp and add in a bridged sub-woofer, but something about the cavity of the cooler itself seems to generate a strong low end kick. It’s very noticable when closed vs. open.
The cooler is great for floating the river and outdoor parties, and although I’ve never had the battery run out on me yet I figure it has at least 8 hours of continuous play before needing a recharge – enough for a really long float! My only complaint about it is that the sound is very directional. If I were doing it again I’d maybe put one speaker on each side of the cooler, or perhaps even on the lid.
Finally and I hope I don’t even have to say this, but don’t put ice or liquids in the cooler! I’ll occassionally keep items that need to be kept dry in there, but the insides are not liquid-friendly so keep your drinks in a different cooler.
I hope you enjoyed this post, comments and questions are welcome!
Keith
July 5th, 2009 at 9:25 pm
Great instructions! Some of my friends are looking at building one….so does the rca headphone adapter that plugs into the amp were good. I thought I was needing to buy a receiver, if not that would be a plus!
Thanks again for the blog!
July 6th, 2009 at 12:31 pm
Wow… I have been searching for years to find something like this. Very cool. I intend to use an old headunit that I have but I needed the basic info you provided. Thanks!
July 6th, 2009 at 8:42 pm
The RCA works fine with an iPod for starters, but I’m actually planning to install a receiver/head unit at some point so that I can control the music from outside the case. The only issue with these units are that they are generally a lot less powerful than a separate amplifier. You can always try the receiver first and if you need more power add a separate amp.
July 17th, 2009 at 11:07 am
Nice how-to, great first time build on a radio cooler. I have built several of them (can find them on youtube by searching ‘radio cooler’). But I do think this may the first how-to online I have on a not forum website. I have a couple thread on forum site with build logs of my projects, wierd how they always seem to keep getting bigger/louder though, lol.
July 17th, 2009 at 2:02 pm
Great directions for this. I do a lot of river runs, and this would be the perfect accessory!
July 17th, 2009 at 2:20 pm
Instead of a head unit, you might try a bluetooth reciever/sender? If the ipod is waterproof you could wear it around your neck and control everything from right there…
July 17th, 2009 at 2:30 pm
So I wanted to post this on How to Build a Stereo Cooler Pt II, but the comments are closed. Just going from the intended purpose of the head unit you bought, my guess is that the Ignition Switch refers to the car’s ignition system, which will supply power to the unit when the key has been turned. I speculate that Memory B+’s constant power is used to keep the clock’s time and the radio presets stored in the unit’s memory.
July 17th, 2009 at 2:35 pm
[...] For a picture by picture walk through, detailed instructions, and a waterproof disclaimer, hit up How to Build a Stereo Cooler. [...]
July 17th, 2009 at 3:48 pm
Love floating the Guadalupe every summer, too bad it’s low as hell. The last cooler radio we did got a bit ridicilous but they are fun projects.
I found installing a wired remote to the outside works best and limits you from having to open the case, something like this
http://www.amazon.com/Pioneer-CDMR80D-Marine-Use-Control-Display/dp/B000VUMXXG
Also you are right, it works best with the speakers on the lid
July 17th, 2009 at 5:06 pm
Thanks Jacob F I think you’re right – I updated the Pt II post.
July 17th, 2009 at 6:25 pm
[...] For a picture by picture walk through, detailed instructions, and a waterproof disclaimer, hit up How to Build a Stereo Cooler. [...]
July 18th, 2009 at 12:21 am
[...] For a picture by picture walk through, detailed instructions, and a waterproof disclaimer, hit up How to Build a Stereo Cooler. [...]
July 18th, 2009 at 9:48 am
Great post. I designed one very similar to this one with an MP3 head unit. I used one of those powerwheel 12 volt batteries and had horrible battery life. I ended up changing it out with a normal small 12 volt automobile battery and it worked wonderfully. We’ve used it on at least 10 river runs and it’s still doing great.
http://www.flickr.com/photos/luisgarcia/135912040/in/photostream/
http://www.flickr.com/photos/luisgarcia/135912080/in/photostream/
Good luck folks.
July 18th, 2009 at 11:08 am
Craig your Radio Wagon is amazing! Great job!
http://www.youtube.com/user/youanimal
July 18th, 2009 at 4:56 pm
You can add to more speakers. That amp can handle 2 ohms and the speakers are 4 ohms.
July 18th, 2009 at 5:16 pm
Hook the speakers up in parallel. It will get your amp hotter but the amp will put out more power.
Oh the blue or green wire will turn on your amp.
July 18th, 2009 at 10:38 pm
[...] For a picture by picture walk through, detailed instructions, and a waterproof disclaimer, hit up How to Build a Stereo Cooler. [...]
July 20th, 2009 at 9:04 am
Solar Panels on the lid to help with charging….lol…just a thought
July 25th, 2009 at 12:25 pm
[...] For a picture by picture walk through, detailed instructions, and a waterproof disclaimer, hit up How to Build a Stereo Cooler. [...]
August 22nd, 2009 at 11:20 am
Keith, Thanks so much for the stereo cooler plans. I just finished my first stereo with 6 speakers installed. The only problem is that I am getting alot of vibration on some music. Did you stuff the speaker holes on the inside with anything? Also, you are showing something on your positive cable? Is this a surge protector for the fuse in the amp? Is this important? How is the stereo grounded? I bought a toggle switch with just on/off but it had 6 connections on the under side. I didn’t know how to hook it up but by trial error I figured out that 1 wire from remote or positive goes to one of the middle connectors on the toggle switch and the other wire from either remote or positive on your amp has to go on the connector on the on side of the toggle switch but also on the same side as the wire you just connected to the middle
connector of the toggle switch. I hope this isn’t confusing! Anyway, I am going to keep messing with my cooler until it sounds right! Probably have to put in better speakers! If anyone needs any info or would like to see pictures of my stereo cooler, e-mail me at michaelc@murray-ky.net Thanks again Keith.
August 22nd, 2009 at 1:35 pm
Mike,
The vibration is probably from the cooler lid or some other loose part of the system. You can test this by holding different parts firm while music is playing and see what dampens the vibration. Once you find what it causing it, fix it with glue or some sticky backed foam bung between surfaces as appropriate.
The box on my positive cable contains a fuse, it came like that in the amp wiring set I purchased, but isn’t necessary I guess if your amp already has a fuse.
The amp is already grounded to the negative terminal of the battery. In automotive audio installation, grounding usually involves attaching to the steel frame of the car, which acts like a wire and is connected to the negative terminal of the battery. It’s not grounding in the sense that high voltage home electrical is, for safety, but is actually part of the circuit.
September 1st, 2009 at 2:52 am
[...] For a picture by picture walk through, detailed instructions, and a waterproof disclaimer, hit up How to Build a Stereo Cooler. [...]
January 5th, 2010 at 11:09 pm
You said you couldn’t find a website that builds them professionally, but I in fact am the owner of a company who does. My website is http://www.tubintunes.com. I have made my products to where it is actually cheaper to buy them through me rather than build them yourself. My background as an installer and inventor has helped me perfect the art of build radio coolers. I even have one that floats by itself down the river. Take a look at the site and let me know what you think about my products. I can be contacted at Delray@brushfireconcepts.com with any comment or questions. Thank you so much.
January 24th, 2010 at 11:32 pm
Hi Keith,
When you hooked your receiver up can it still play from your ipod?
January 24th, 2010 at 11:52 pm
Also Keith if you decide to use 4 speakers, would you need any additional appliances?
January 30th, 2010 at 10:59 am
For four speakers, you would need to buy a 4-channel amp. They’re not much more expensive. On your iPod question, yes you can still connect it by switching connections from the receiver. Alternatively, you can buy a higher end receiver that has iPod integration.
February 12th, 2010 at 5:29 pm
I would put the battery in a battery box and vent it outside to reduce corrosion proplems to your equipment and reduce any chance of explosion.
February 13th, 2010 at 9:42 am
Keith,
Building a stereo cooler for the baseball park while attending my son’s games. It’s definitely going to be cool having it at the ballpark, however, I’m a pure novice when it comes to hooking up stereo equipment. I’ve followed the instructions to a tee but somehow can’t get any power to my amp. I’m using a 10 gauge install kit, a 12V mower battery, a 600W JVC amp and switch from radioshack. I have everything connected exactly like you have it in your amp photo. Fuses are good. I’ve even tried taking the switch out of the loop. Just can’t get the amp to power up. Any suggestions?
February 13th, 2010 at 11:23 am
It sounds like you have everything set up right, but check to make sure that you have the hookups the right way round, +12V to battery + and GND to battery -. Also, I think the amp itself might have a small inconspicuous power switch you need to turn on. Failing that, you probably need to start testing the individual components with a multi-meter (these cost as little as $15). Touch the multi-meter pins to the terminals on +12V and GND on the amp while everything is connected. If you get a voltage, then it’s probably the amp that is DOA. If you don’t get a voltage test the battery terminals to determine whether the battery is flat or the cables are bad. Good luck!