This is my home made mp3 player that mounts under the passenger's seat. Inside the case is a Pentium 233, 64MB of memory, a 10GB hard drive, and a slimline cdrom drive. To fit under the seat, the passenger seat position lever was removed and the seat is now bolted into place. I have had a mp3 player in my car for over 4 years now, starting out as a motherboard laying on the floor and wires everywhere. Since then it has continually evolved into the player described on this page.
	The software is a minimal install of Slackware Linux, and XMMS. I wrote a small plugin for xmms that allows me to use my AST/Logitech remote control. To provide fast startup and shutdown, the system mounts the hard drive in read only mode and loads only the bare minimum drivers and software in order to run. Since the drive is read only, I can power off the computer without shutting down first.
	My display is a sharp 6 inch active matrix color LCD from eio.com for $100. Last I checked they were out of stock. The display came from them bare, so I had to build a power supply according to the directions given on their site. The screen accepts a NTSC (television) signal, so I use a Trident card in the computer with TV output to drive the display.
	My MP3 player now has network connectivity! Since the computer has no free PCI slots, I had to get a USB wireless network adapter. Thanks to the linux-wlan project, the Linksys WUSB11 Version 2.5 adapter is supported in Linux. It uses the Intersil Prism 2.5 chipset. The adapter is cheap (can be found for < $100) and for me has provided good performance. MP3s download to the car at about 525KB/sec. I use rsync to mirror the mp3 collection from the house to the car. I use this script to download all the new songs, and this script to rebuild XMMS's playlist.
	The sound card is a Zoltrix Nightingale digital sound card fed into a MidiMan Flying Calf external 24 bit professional digital to analog converter. The zoltrix card is cheap ($20) but provides bit-perfect digital output. Inside your computer there is too much interference for high quality audio, so the external flying calf was the perfect choice, there is absolutely no audible noise.
	After the digital audio signal is converted to analog by the flying calf, it passes through my AudioControl Master Volume Control. This is required because a true digital signal has no volume control. The MVC controls the volume from the trunk, a remote wire runs to the front of the car to a knob mounted next to my power switch to adjust it.
	From there the audio runs to the trunk and into my AudioControl EQX 13 band equalizer for fine tuning the overall frequency response. Next comes my Precision Power PC6600.2 amplifier which gives plenty of clean power to all the speakers from a single amp. All equipment in the trunk mounts in the spare tire well.
	Speakers are the most important piece of an audio system. I listened to dozens of models before I chose the Boston Acoustics Rally RC51 component speakers. The rear is filled with the Rally RX97 6x9 speakers at low volume to prevent destroying the imaging from the fronts. I used a signal generator and a dB meter to fine tune my EQ to ensure the best in-car frequency response I can get.
	To fill in the bottom of the frequency range I use an Image Dynamics IDQ 10 inch subwoofer. I have the dual 2 ohm model wired in series giving my amp the 4 ohms it requires bridged. This is a wonderful sub for the money, and it only requires a 1/2 qubic foot enclosure (which took me all day to build). When turned up, the headlights would dim to the bass, so a 1 farad Lightning Audio Bolt series capacitor was used to smooth out the car's voltage.
	The music styles I listen to is progressive metal and classic rock. Bands include Dream Theater, Symphony X, Ayreon, Spock's Beard, and many more. I find good CDs by downloading mp3s, if I like the music I purchase the CD and encode my own mp3s using cdparanoia and LAME, encoded at 192kbps. This way I can ensure high mp3 sound quality and the band gets the CD sale.