If you're tired of the plain old white leds that provide the back light behind your dashboard, check out this project. It gives a quick look at how you can alter your stereo setup and replace the leds (blue leds look especially cool). It's a quick and easy job and likewise, the write-up is short and to the point.
This project is as intuitive as it is easy to build. Need some disco lazers? No problem! Just strap them onto some old blown speakers and watch the light show (there's a little more to it than that).
The LED Color Organ is another project that lights up LEDs in a new, cool & different way (using audio signals). The soldering job this guy did for space saving was just down-right crazy but it works. He has step by step photos, schematics and everything you'd need to build it.
Taking a bit of a break from the standard electronics DIY's, here is a cardboard and duct tape speaker box DIY. It's a seemingly pointless design, but a working design none-the-less. Give it a look for some light weekend reading.
Ever since hardware mp3 decoders became commercially available, DIY mp3 players have been seen sprouting up all over the place. This project write-up describes the processes of creating an mp3 player with a display using a standard microcontroller (a PIC).
The CMoy Pocket Amplifier has been famous for quite a while. For those of you who haven't heard of it, it is a little audio amplifier for headphones that fits inside a mint case. This project write-up is excellent if you want to build one for yourself.
Using a standard straight to USB (via EZ-USB) connector and re-wiring a keyboard a little bit, creates a nice MIDI input device. This project write-up details the process out and provides all hardware schematics & software needed.
This is a very, very informative write up on how to generate different types of sound using an Arduino. While it sounds like a simple thing to do, generating complex sound is a rather difficult task.
For all you guitar enthusiasts out there, here's a nice little setup for getting your own guitar effects going. It takes the audio input and throws it all onto a breadboard for you to manipulate. It's a cool little setup, check it out.
In a small change from the norm, here are a plethora of DIY guides for building speaker systems & boxes. So if you're an audiophile be sure to check out this page, you won't be disappointed!