Building Your Own Linux Based Audio Component

by: Bryn Dole ( dole @ atomicwidget . com )

Introduction

One day I decided I needed a Linux based stereo component to unify all my music. I NEEDED it you see. I'd been reading slashdot's occasional articles on music and MP3 devices. I've had discussions with friends and co-workers that all dream the same dream. I've heard and read about people building similar machines, but none just like I wanted. Is it possible to will such a device into being? Here is the chronicle of my project to build the ultimate Linux audio device.

Feature list

Every product needs a list of features:
  1. Linux based for stability, access to tools (grip, WinAmp for Linux, NFS, SAMBA, KDE, Konqueror, ssh, etc.)
  2. Play music: MP3, wav, Ogg, audio CDs, mp3 cds, streamed MP3s
  3. Rip music CD-ROMs
  4. Create music and/or MP3 CDs
  5. Network access - remote NFS and SAMBA mounting of disks with music, gnutella access
  6. Small cool looking case
  7. Quiet
  8. High fidelity sound card - RCA and optical out, very low signal to noise ratio ( > 90db)
  9. TV-Out so it can be integrated into my entertainment system without an extra monitor
  10. Wireless keyboard/mouse/remote
  11. Much Storage - enough for several hundred CDs of music with lossless compression, and additional MP3s, Ogg, from the net.
Pipe dream features: I passed on building the next generation TiVo. After all, I already have a DVD player and a TiVo. Both work great, and I don't NEED a Linux PVR/DVD-ripper (yet). That and the DVD-RW drive was going to add to the overall price. When the price drops, I'll swap out the CD-RW with a DVD-RW and add the necessary software. I may do this soon...

Components

My shopping list:
  1. High fidelity sound card [MidiMan Delta DiO $300]
  2. Decent CPU speed - enough for trip'n WinAmp visualizations [900 MHz Celeron $75]
  3. Graphics card w/ TV-out & Linux support - [NVIDIA GeForce2 MX-400 GPU $115]
  4. Memory - is cheap! [128MB SDRAM $25]
  5. Compact and Cool looking case [FIC Sabre 1815 $270]
  6. Baby ATX motherboard with onboard 100Mb Ethernet [ incuded with the FIC Sabre $0]
  7. Disk Drive [60GB $80]
  8. CD-RW [$90]
Total cost: $955
Prices are circa Dec 2001

Software

You have to have software. The less coding the better, so I stitched together a whole host of available software.
  1. Linux RedHat 7.2 8.0
  2. KDE/GNOME
  3. ssh
  4. nfs
  5. samba
  6. WinAmp for Linux XMMS w/ ALSA, flac, and crossfade plugins
  7. ALSA drivers for MidiMan sound card
My original plan was to use WinAmp for Linux displayed to the TV-Out as the primary UI. The thought of parties where my guests choose their own music, kick back, and watch the trippy WinAmp visualizations gets me tingly. I used to work with Keith Peters, the coding god, who did the Linux port of WinAmp 3. However, WinAmp 3 requires a dual processor 2.5GHz Xeon processor system to run its bloated GUI, so I'm going with XMMS instead. XMMS has matured since I started this project and the ALSA integration is much better now.

Sorting Out the Details

The first part I started looking for was the sound card. I've been listening to MP3s and CDs on computers for years and the one unifying element was that the audio sucked. The sound was awash with noise, hiss, buzz, pops, etc. My Sun Ultra2 was so bad you not only heard the disk drive through the headphone jack, you could actually hear the mouse move across the screen. As the framebuffer's contents changed the buzz in the headphones would buzz and pop as windows gained and lost focus. If I was going to hook this into my stereo there was going to be zero tollerence for noise. So I did my reaserch, I found this sound card comparison. I went through the list looking for a card that showed up on the ALSA soundcard compatibility list. I checked out the online specifications for some of the boards listed on the ALSA page and did extensive Googling for sound card reviews. I also discovered that optical digital out was available, which instantly got added to the "must have" feature list. In the end I narrowed my choices down to several MidiMan cards and one from RME.

Other contenders included several boards from Turtle Beach.

It was not until after I purchased my card that I found a good How-To guide on Linux Audio Quality. This site has good suggestions for fixing your current audio card and shopping for a good one. Most of the information is aimed at getting the most of of cheap audio cards.

1U is Not 4ME

The next item on the list was a good looking case. My first impulse was to get a 1U case: rackable computing in your den. After researching 1U cases I realize several severe limitations of the 1U format. There is only space for at most one PCI card, which requires a L-shaped addapter so the card lays flat. I was probably going to need two cards: 1 sound and 1 video w/ TV-out. Other negatives were: cost, limited number of available motherboards, and while very flat, 1U cases are wide and long. Less than ideal for installing in my home entertainment center.

Small Packages

I ultimately decided to go with the mini-tower. I wasn't happy about this but I wanted to get started and a mini tower would have the space and flexability to allow me to install my PCI cards, find an inexpensive motherboard, and work out the kinks. So I headed to Fry's. That is when fate intervened. I discovered a small silver case, motherboard included in about the same form factor as a small VCR. The FIC Sabre 1812 had everything I needed right on the mainboard: Ethernet, AGP-VGA, Sound, and IDE. Things only got better after I got home and discovered that its BIOS allowed for netboot via the PXE protocol. The bootloader GRUB that comes with RedHat 7.x supports netboot using PXE, allowing me to turn my machine into a diskless terminal/device. If you don't like GRUB, I found another Linux bootloader called SYSLINUX.

The build quality on the Sabre blew me away. Tolerances were tight, very tight, and everything fit just right (except my oversized PCI video card, that forced my to kick out the drive and go diskless). The case came with specially cut/wrapped/shaped cables. I haven't seen a compact case fit together so well since I opened an old Sun IPX cube.

The downside to the Sabre is the BIOS. For some reason the power button is flaky, and seems to alternate between power-off and standby. It also seems to frequently boot-up without recognizing the PCI nVidia card I installed.

The FIC Sabre 1812 Case

Front View
Front View
Back View
Top View

The other case I considered was the Shuttle SV24 Barebones. The pros were built in S-video and composite video out, more space in the case and its aluminum exterior. The Cons were: only one PCI slot that requires a L-shaped adapter, unknown support for the TV-out under Linux, and it is the wrong shape to stack with my stereo, DVD player, and TiVo.

The other alternatives were custom built boxes like the GCT-ALLWELL. Anders Brownworth is already building just such a MP3 device using the GCT-AllWELL.

Motherboards

A small case necesitates a small motherboard. I needed as many features as possible on the motherboard because PCI and AGP cards take up space. ATX and baby ATX boards were the way to go. Thankfully with the popularity of 1U and 2U servers, there are plenty of feature packed motherboards to choose from. Ethernet was a must. Sound and video were nice to have. On board sound was never going to cut it for my quality requirements on the sound output, and finding onboard TV-out was pretty rare. Finding a TV-out with Linux support proved impossible.

My case selection (the FIC Sabre 1812) made my motherboard choice for me. The onboard AGP VGA, and sound were a waste for me. I was installing my high-end audio card and needed TV-Out, so I disabled the onboard sound and video via the BIOS. Other people might have different needs. I used the onboard VGA and sound during my initial installs. Both worked great without any hassles at all using the standard RedHat 7.2 install.

Side Note on RH 7.2

Not that RH7.2 didn't create problems, somehow my first install attempt left out rpm, as in the rpm binary! Upgrading was impossible, so I reinstalled with different packages and things got better. Why is lynx left out of the WWW/Mail RPM group? Why is mrtg installed into the /etc/crontab by default? What kind of crack are they smoking at RH these days. On top of that they foo'd up thier up2date system. <end rant>

CPU and Memory

Thanks to the ever plummeting cost and ever increasing speed of CPUs, this was an easy decision. I originally planned to get a 500MHz Celeron, but got talked into the 900MHz one by the sales guy at Fry's. So I shelled out a whopping $75 bucks instead of $45. The upside is the 900MHz Celeron uses a 100MHz frontside bus instead of 66MHz. Overkill for MP3, but allows for faster MP3/OGG encoding and possible future video capture.

Likewise for memory: $25 buys you a 128MB SDRAM PC100 DIMM. No reason to settle for less, or to need more.

Video

Because I don't want to be tethered to my computer to play music and I wanted my Linux Audio Component to be completely integrated into my entertainment center, I decided the system should display through the TV. While there are a number of video cards that now support TV-Out, as a discovered few support TV-Out using Linux Video drivers. In fact, I only found one such card, the nVidia GeForce2 MX series. Depending on the manufacturer (there are several that use the nVidia GeForce2 chip-set) and the model. The GeForce2 "MX DH" and "MX400" usually have TV-out.

I found the right nVidia card the Asus V7100 PRO/T 32MB MX-400 PCI Video Card w/TV-Out at Googlegear.com for $99. This card is a half-height card and fits into the third half-height slot in the Sabre's case. It is also shorter than the ATI all-in-wonder, leaving room to reinstall the hard drive if I so choose. I haven't decided whether to re-install the HD or not, the net-boot is fast and reduces the noise and heat.
GeForce2 MX 400 Installed
I tried for aver a week to get the nVidia supplied drivers to install and work under RedHat 7.2. The prepackaged RPMs that nVidia supplied were all broken, it looks like they compiled with the wrong kernel source tree. I downloaded the nVidia source and got that to install, after the usual headaches. However, TV-out was Dead on Arrival. If I tried to start X with TV-out enabled, the whole system would freeze. Not just X, the kernel would give itself a big wedgie, without so much as an error message. Maybe because I'm using PCI and not AGP, or maybe because nVidia's Linux drivers just suck.

I was about to give up on TV-out when I discovered a stand alone tool that will set the TV-out mode on nVidia drivers. The nVidia TV-out control can be found at http://sourceforge.net/projects/nv-tv-out/. You can even run the application from the command line and include it in the init scripts. There is full support for NTSC, NTSC-J, PAL, etc. I've only tested the NTSC mode. While the display isn't perfect (hey its TV after all), the main problem is finding a mode that maximizes pixels and minimizes the wasted space around the edge of the X windows screen. For some reason the unused regions above and below the video is hot pink.

How NOT to get TV-out working

Failed method 1

My first attempt at TV-out under Linux was with a very expensive ATI Radeon All-in-Wonder card. I've been pretty loyal to ATI after a long string of ATI cards working in the last three Linux boxes I built. However, while it worked great as a graphics card, I could get not TV signal. As soon as Linux started booting, poof, the screen would get all jangly. After more extensive Googling, I found ATI's Linux driver page. The ATI FAQ says it all:

Is TV Out support available for ATI products under Linux?
ATI is investigating the possibility of supporting TV Out under Linux. Please refer back to this web page to keep up to date on developments regarding TV Out support.

Failed method 2

I'm including this information in hopes that one day nVidia will fix its drivers and this may be of help to someone. For now, use the nvtv application I mention above.

Here is the nVidia TV-out How-To from Linuxhardware.org. This How-To is slightly out of date. For the latest information consult the official documentation on how to install the nVidia drivers from the nVidia web site. Here is the Linux text documentation and the pdf documentation from nVidia.

Audio Drivers

Choosing the MidiMan Delta DiO 2496 meant that I no longer had pre-compiled/pre-configured sound support in the kernel. I was going to need to install the ALSA sound drivers and OSS emulation libraries. The "e;stable"e; version of the ALSA drivers is at 0.5.x, but this code is ancient, most of the support for the ICE1712 chip (in the MidiMan cards) only appears in the 0.9.0beta10 drivers. Don't bother with the old 0.5 version, and use the 0.9.x version.

Building ALSA is pretty easy. Its the standard: ./configure; make; make install process. Documentation is scarce and most has not been re-written since the 0.5 version of the divers. The best resource for installing ALSA is at: Planet CCRMA at Stanford university. I found this site too late, but this site has already documented most of the pitfalls that I had to work through the hard way.

Update: The ALSA 0.9 branch is now the official stable release! Here is a good link for getting ALSA installed: Installing and configuring ALSA, JACK, & Ardour I found the best way was to download the source packages yourself and make and install them.

Barely Documented ALSA

There are several fixes you need to implement to run ALSA and the ALSA OSS emulation smoothly. For instance you'll want to load the ALSA devices and modules automatically at boot time. So you'll need to install the /etc/init.d/alsasound script into /etc/rc.d/rc5.d/ and made the modifications mentioned in this patch message. Another item is to edit your /etc/rc.d/rc.sysinit file and remove the standard sndconfig call that might munge some of you sound settings. Comment out the following lines: 

if [ -n "$PNP" -a  -f /proc/isapnp -a -x /sbin/sndconfig ]; then
    /sbin/sndconfig --mungepnp >/dev/null 2>&1
fi

I'm still having issues with permissions of /dev/dsp0, /dev/audio0, and /dev/mixer0/. OSS emulation only works for root, until I go through and change the permissions to be read-writable by the user. Just a matter of automating this...

Storage

I purchased a 5400rpm 60GB drive from Fry's for $80. I chose the slower drive speed because it generates less heat and it was cheaper. This is enough storage for about 70+ CDs in raw wav format. Using FLAC (Free Lossless Audio Codec) I can double that to about 140+ CDs worth of data. My legacy MP3s and Ogg files will be mounted via NFS from my main Linux machine in my home office.

Software

Now its just a matter of glueing it all together with software.

XMMS

I wanted to use Linux WinAmp, but currently it too unstable. So I opted for the best alternative: XMMS.

XMMS plugins

I now have the ALSA, FLAC, and crossfade plugins installed and working with XMMS.

Because I use KDE wich comes with aRts installed. I installed the aRts XMMS output module available in rpm or source form. Now I can hear KDE sound events while playing audio.

I've yet to start playing with the many other XMMS modules....

KDE

This is a work in progress. More to come...

Sound Formats

Existing Commercial Products

Here is a list of similar commercial products I've discovered:
  1. AudioReQuest ARQ2 Pro cost ??
  2. Rio Advanced Digital Audio Centee for $1499.95
  3. ZapMedia Station for $1499
  4. HP de100c for $999.99
  5. Bokks for $499
  6. Audiotron for $299.95
  7. Rio Digital Audio Receiver for $199.95 (requires a PC to host music) [review]
The feature sets of these products is quite varied. A common theme is small hard drives and dependence on an external windows machine to adminster and rip music. The ARQ2 is your high end, "e;money is no object"e; version for those who wish to outsource the ripping of their CD collection.

Conclusions

In theory, building a Linux audio component is easy (at least according to half the posters on Slashdot). However, I chose several design elements that made it more challenging: 1. a very small form factor 2. high-fidelity audio 3. TV-out for display. Eliminating these requirements would have made my life a lot easier. But then I might as well listen to my music through a set of crappy little speakers. Compromise was not an option.

I hope that the information here helps others build their own Linux Audio Devices. If you do, email me. (see above for email)

TODO list

  1. Buy a new receiver/stereo with more video-in/out, S-video, and digital audio connectors. I'm maxed out!
  2. Download install FLAC and FLAC XMMS module
  3. Convert .wav files to FLAC format (50% space savings)
  4. Investigate remote control options (IR, RF, etc)
  5. Investigate web control interface.
  6. Investigate IR remote contol options.
  7. Try to get Linux WinAmp working.

Resources and Links

I kept my web research organized in my Dmoz.org Bookmarks. The latest Linux news from Topix.net.

by: Bryn Dole ( dole @ atomicwidget . com ) Last modified: Sun Mar 21 00:05:49 PST 2003