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With all of the interest in my cassette boombox audio mod I decided to write up a complementary tutorial - reusing computer speakers. Modifying a boombox for an audio input is great for portable applications, but reusing a pair of computer speakers is more suitable for more permanent installations and cases where you need some physical separation between the left and right channels.
Used powered computer speakers are extremely inexpensive. Theyíre generally sold at yard sales and thrift stores for $5 or less, including their "wall-wart" power supplies. These speakers generally have permanent audio input cables with a 3.5 mm stereo (mini) plug which plugs into your computerís line out port (typically color coded lime green).
These arenít fantastic state-of-the-art speakers youíd want to use for a high end home theater system, but theyíre decent, and certainly worth the price. Occasionally Iíll come across computer speakers with a subwoofer (a large speaker designed to replicate bass sounds) very inexpensively too. Theyíre called 2.1 (pronounced two dot one) because they have two main speakers plus one subwoofer.
There are many ways computers speakers can be reused - add stereo speakers to a DVD player, inexpensive amplified speakers for an MP3 player, a high quality speakerphone for your cell phone, and to add surround speakers to your computer to name just a few possibilities. Basically any piece of electronics with a standard 3.5 mm (mini) audio output jack can be used.
Step 1: How to hook up a DVD player
You can use a pair of speakers and an inexpensive adapter cable to upgrade your home video setup from mono to stereo.
Almost all DVD players, Blu-Ray players, and stereo VCRs have a trio of color-coded output jacks. Theyíre typically colored yellow, white, and red and correspond to Video, Left audio, and Right audio. The good news is different hardware and cable manufacturers all use the same color coding scheme. (It was much more challenging to hook up early VCRs and audio equipment before color coded standards became popular.) Red is also used on red/green/blue colored cables for component cable setups and yellow is also often used for digital audio (SPDIF) so youíve got to be careful not to confuse them. Other than that all you have to do is match colors to avoid confusion when hooking up cables.
An inexpensive Y-adapter cable with white and red RCA plugs on one side and a female 3.5 mm stereo plug on the other end is all you need to hook up most computer speakers to your DVD or Blu-Ray player or stereo VCR.
Some mini stereo plugs and jacks are color coded lime green, but this isnít always the case. In most cases, including most adapter cables, the 3.5 mm plug is the same color as the cable (beige, black, and white are common).
In a typical setup your TV set is hooked up to the DVD player with either a direct cable from the DVDís video out to the TVís video in jack or through an R-F modulator to the televisionís antenna jack. If a mono TV has input jacks they will be color coded yellow (video) and audio (white).
If the red and white audio out jacks on your DVD player are not in use then hook up the Y-adapter cable and plug in the speakers. Presto, youíve got the equivalent of a stereo TV and added a new dimension of experience to your DVD watching enjoyment.
Step 2: Mono and Stereo at the same time
If youíve already got an audio cable hooked up from the DVD player to the TV set youíve got a couple of choices. You can disconnect the audio cable from the DVD player to the TV and hook up your computer speakers (no sound will come out of the TVís speaker), or use a splitter so the mono audio still goes to the TV while the stereo audio goes to the speakers. An inexpensive RCA Male to two RCA Females splitter will do the job. (An adapter changes one type of connector to another while a splitter takes a signal and splits it into two identical signals.)
My preference is to use the splitter because it gives extra flexibility. If Iím just watching an ordinary DVD then Iíll just use the TVís built-in speakers and leave the speakers unpowered. But if itís an action movie with lots of audio effects or a musical Iíll turn on the external speakers.
The first photo shows a gray colored splitter cable plugged into the DVD playerís white (left/mono) audio jack. The white cable from the adapter is plugged into the splitter and the red cable on the adapter is plugged into the red audio output jack (hidden underneath the gray splitter cable in this photo). The speakers are connected to the other end of the adapter. The other half of the splitter sends the left audio channel to the television, along with the existing yellow (video) signal.
Hooking up external speakers to your DVD player has an added bonus; the DVD player can also be used as an audio CD player. Just leave the TV set powered off. Put an audio CD into your DVD player and you can listen to CDs through the stereo speakers.
Step 3: Other uses
Another use for computer speakers is amplified speakers for an MP3 player. Just plug the speakers into your MP3 player and youíre ready to listen to music without headphones.
My cell phone has a 3.5 mm audio jack. When itís plugged into speakers it can be used as a speaker phone or listen to a podcast. The phoneís built-in anti-echo circuit does a great job of eliminating feedback. If your cell phone doesnít have a mini jack you can probably obtain an adapter cable.
Step 4: Surround sound on your computer
Many high end computer sound circuits have the capability to hook up extra speakers for a surround sound setup. In some cases the jack is marked "Rear/Line In" or just "Line In" and that jack serves dual purposes. Depending on how your sound circuit is configured the jack can either take audio into your computer (Line In) or send out audio to a pair of rear speakers. In other cases thereís a separate jack marked "Rear", and possibly an additional jacks for Center/woofer and side speakers for a 5.1 or 7.1 audio setup. Check your sound cardís documentation for details.
This figure shows the jacks on my ASUS motherboard (unless youíve got a similar motherboard the jacks will probably have a different arrangement). Jacks 5, 6, 14 are the standard line in (light blue), line out (lime green), and mike (pink) jacks. Jacks 3, 4, and 15 correspond to the side, center/woofer, and rear speaker jacks. Since this motherboard also has digital audio outputs (17 and 18) it can hook up directly to a home theater system.
Step 5: Final thoughts
I pick up used speakers at yard sales whenever theyíre inexpensive enough because they are so versatile. Iíve paired them with MP3 players as presents, helped friends upgrade their DVD setups to stereo, and set up one unit in a laboratory so anybody could hook up an MP3 player if they wanted background music while they worked.