Sox is a very handy sound conversion utility which I'd recommend having, and you will need it if you wish to
use wavnorm.
ftp://sunsite.unc.edu/pub/Linux/apps/sound/convert/
You may also need a mixer program; Xmixer works well and is included with most distributions.
8. Setting up your system.
This section will describe the basics of setting up your Linux system to record audio from either an analogue
or CD−ROM source.
I'm basing this section around my Intel based Linux system which is running Redhat, but should be
reasonably distribution neutral. If you have any success in using this HOWTO on other hardware, please get
in touch.
Naturally a reasonable prerequisite is a working soundcard. At this point in the HOWTO, I invite you to read
the excellent Linux Sound HOWTO, by Jeff Tranter. After which a good read of the Linux Sound Playing
HOWTO, by Yoo C. Chung. Both of the above mentioned HOWTO's cover the details of getting a sound
system working under Linux far better than I could.
8.1 Setting up for Analogue Audio Capture
Firstly, set up your audio. There are a multitude of ways to route audio before it gets to your Linux box, some
common ones are:
Line out to Soundcard Line in. Most audio devices have a Line output sockets. Line level is a standard that
specifies what voltage the audio device will send out. If I remember correctly it is 500mV for domestic and
Semi Pro devices, and 750mV for Pro audio devices. I would guess that the standard set for most soundcards
will be 500mV, but some of the newer Pro audio may be to the higher standard It shouldn't make too much
difference unless you are recording at very high levels.
The Line level output is normally used to connect HI−FI equipment to an amplifier, so things such as Tape
Decks, Radio Tuners, CD players, DAT machines and Mini−Disc players should connect without problem.
Turntables can be more of a problem, see below for more information.
You could capture audio from VCR's as well. Most VCR's will either have Line out for sound, or you can Get
a Line out from a SCART socket if your VCR has one.
Amplifier Tape out to Soundcard Line in, Soundcard Line out to Amplifier Tape in. This configuration is
essentially replacing a traditional tape recorder connected to your HI−FI amplifier with your Linux system.
The Soundcard Line out to Tape in allows monitoring of the recording levels.
Mike to Soundcard Mike in. The voltages generated by microphones is very much smaller than those used in
Line level devices. If you were to plug a Microphone into the Soundcard Line in, chances are you would
never record anything.
WARNING, doing the reverse, plugging a Line level device into the Soundcards Microphone input, can
The Linux MP3−HOWTO
8. Setting up your system. 12
