This section lists the sound cards and interfaces that are
currently supported under Linux. The information here is based on the
latest Linux kernel, which at time of writing was version 2.4.4. This
document only applies to the sound drivers included with the standard
Linux kernel source distribution. There are other sound drivers
available for Linux (see the later section entitled Alternate Sound
Drivers).
For the latest information on supported sound cards and features see
the files included with the Linux kernel source code, usually
installed in the directory
/usr/src/linux/Documentation/sound.
The information in this HOWTO is valid for Linux on the Intel
x86 platform.
The sound driver should also work with most sound cards on the
Alpha platform. However, some cards may conflict with I/O
ports of other devices on Alpha systems even though they work
perfectly on i386 machines, so in general it's not possible to tell if
a given card will work or not without actually trying it.
Users have reported that the sound driver was not yet working on the
PowerPC version of Linux, but it should be supported in
future.
Sound can be configured into the kernel under the MIPs port
of Linux, and some MIPs machines have EISA slots and/or built in sound
hardware. I'm told the Linux-MIPs group is interested in adding sound
support in the future.
The Linux kernel includes a separate driver for the Atari
and Amiga versions of Linux that implements a compatible
subset of the sound driver on the Intel platform using the built-in
sound hardware on these machines.
The SPARC port of Linux currently has sound support for
some models of Sun workstations. I've been told that the on-board
sound hardware works but the external DSP audio box is not supported
because Sun has not released the specifications for it.
A number of different types of sound cards exist, reflecting the
different bus architectures available. Here is a brief overview of the
more common types and their distinguishing features.
ISA bus cards are among the oldest sound cards
using the original (non Plug and Play) ISA bus. These typically use
jumpers to select hardware settings for I/O addresses, IRQ, and DMA
channel. You are unlikely to find any of this type manufactured today.
ISA Plug and Play cards use the extended version
of the ISA bus that supports software identification and configuration
of card settings. Few of these, if any, are still being manufactured.
PCI bus cards use the higher bandwidth PCI bus
which provides identification and configuration of cards in
software. The majority of sound cards manufactured today now use
PCI. Most motherboards that provide on-board sound hardware also make
use of the PCI bus.
USB is a newer bus architecture for external
hot-pluggable devices. In theory USB bus sound cards could be
developed, but I am only aware of USB-bus speakers being sold
currently.
The following sound cards are supported by the Linux kernel
sound driver. Some of the items listed are audio chip sets rather than
models of sound cards. The list is incomplete because there are many
sound cards compatible with these that will work under Linux. To add
further to the confusion, some manufacturers periodically change the
design of their cards causing incompatibilities and continue to sell
them as the same model.
A word about compatibility: even though most sound cards are claimed
to be SoundBlaster compatible, very few currently sold cards are
compatible enough to work with the Linux SoundBlaster driver. These
cards usually work better using the MSS/WSS or MAD16 driver. Only real
SoundBlaster cards made by Creative Labs, which use Creative's custom
chips (e.g. SoundBlaster16 Vibra), MV Jazz16 and ESS688/1688 based
cards generally work with the SoundBlaster driver. Trying to use a
SoundBlaster Pro compatible 16 bit sound card with the SoundBlaster
driver is usually just a waste of time.
The Linux kernel supports the SCSI port provided on some sound cards
(e.g. ProAudioSpectrum 16) and the proprietary interface for some
CD-ROM drives (e.g. SoundBlaster Pro). See the Linux
SCSI HOWTO
and
CDROM HOWTO
documents for more information.
A kernel driver to support joystick ports, including those
provided on some sound cards, is included as part of the 2.2 and
later kernels.
Note that the kernel SCSI, CD-ROM, joystick, and sound drivers are
completely independent of each other.
Sound support in the Linux kernel was originally written by Hannu
Savolainen. Hannu then went on to develop the Open Sound system, a
commercial set of sound drivers sold by 4Front Technologies that is
supported on a number of Unix systems. Red Hat Software sponsored Alan
Cox to enhance the kernel sound drivers to make them fully
modular. Various other people also contributed bug fixes and developed
additional drivers for new sound cards. These modified drivers were
shipped by Red Hat in their 5.0 through 5.2 releases. These changes
have now been integrated into the standard kernel as of version
2.0. Alan Cox is now the maintainer of the standard kernel sound
drivers, although Hannu still periodically contributes code taken from
the commercial driver.
The commercial Open Sound System driver from 4Front Technologies tends
to be easier to configure and support more sound cards, particularly
the newer models. It is also compatible with applications written for
the standard kernel sound drivers. The disadvantage is that you need
to pay for it, and you do not get source code. You can download a free
evaluation copy of the product before deciding whether to purchase it.
For more information see the 4Front Technologies web page at
http://www.opensound.com.
Jaroslav Kysela and others started writing an alternate sound driver
for the Gravis UltraSound Card. The project was renamed Advanced
Linux Sound Architecture (ALSA) and has resulted in what they
believe is a more generally usable sound driver that can be used as a
replacement for the built-in kernel drivers. The ALSA drivers support
a number of popular sound cards, are full duplex, fully modularized,
and compatible with the sound architecture in the kernel. The main web
site of the ALSA project is
http://www.alsa-project.org.
A separate "Alsa-sound-mini-HOWTO" is available which deals with
compiling and installing these drivers. The ALSA drivers may move into
the standard Linux kernel as part of the 2.5 kernel development.
Markus Mummert
(mum@mmk.e-technik.tu-muenchen.de)
has written a driver package for the Turtle Beach MultiSound (classic), Tahiti, and Monterey sound
cards. The documentation states:
It is designed for high quality hard disk recording/playback without
losing sync even on a busy system. Other features such as wave
synthesis, MIDI and digital signal processor (DSP) cannot be
used. Also, recording and playback at the same time is not
possible. It currently replaces VoxWare and was tested on several
kernel versions ranging from 1.0.9 to 1.2.1. Also, it is installable
on UN*X SysV386R3.2 systems.
It can be found at
http://www.cs.colorado.edu/~mccreary/tbeach.
Kim Burgaard (burgaard@daimi.aau.dk)
has written a device driver and
utilities for the Roland MPU-401 MIDI interface. The Linux
software map entry gives this description:
A device driver for true Roland MPU-401 compatible MIDI interfaces
(including Roland SCC-1 and RAP-10/ATW-10). Comes with a useful
collection of utilities including a Standard MIDI File player and
recorder.
Numerous improvements have been made since version 0.11a. Among other
things, the driver now features IRQ sharing policy and complies with
the new kernel module interface. Metronome functionality, possibility
for synchronizing e.g. graphics on a per beat basis without losing
precision, advanced replay/record/overdub interface and much, much
more.
It can be found at
ftp://www.ibiblio.org/pub/Linux/kernel/sound/mpu401-0.2.tar.gz.
Another novel use for a sound card under Linux is as a modem for
amateur packet radio. The 2.1 and later kernels include a
driver that works with SoundBlaster and Windows Sound System
compatible sound cards to implement 1200 bps AFSK and 9600 bps FSK
packet protocols. See the Linux AX25 HOWTO for details (I'm a ham
myself, by the way -- callsign VE3ICH).
An alternate sound driver is available that requires no additional
sound hardware; it uses the internal PC speaker. It is
software compatible with the sound card driver, but, as might
be expected, provides much lower quality output and has much more CPU
overhead. The results seem to vary, being dependent on the
characteristics of the individual loudspeaker. For more information,
see the documentation provided with the release.
The latest version of the PC speaker driver can be found at
ftp://ftp.infradead.org/pub/pcsp/.
Another option is to build a digital to analog converter using a
parallel printer port and some additional components. This provides
better sound quality than the PC speaker but still has a lot of CPU
overhead. The PC sound driver package mentioned above supports this,
and includes instructions for building the necessary hardware.