Sound cards are not only used for audio
output, but also recording audio from a variety of external sources.
While the connectivity options for sound cards vary greatly from the
professional level to consumer grade, common external-audio source
connections include the following:
- MIDI port – Musical Instrument
Digital Interface (MIDI)
is an industry standard interface used to connect musical devices.
The basic MIDI devices are controllers and generators. Musicians
often use MIDI-enabled computers to control and sequence music
generators such as drum machines and synthesizers. Most sound
cards have a MIDI/Joystick combination port. This is commonly a
female DB-15 port on the face of the sound card. A MIDI cable is
used to connect one or more devices to the sound card. Special
software is required to use the MIDI functions of a sound card and
is usually included as part of the software package.
- Microphone in port – Microphones can
be connected to a sound card using the female 3.5mm mini jack port
on the face of the sound card. This provides users with the
ability to capture their voices using a recording application on the
computer. Inputting audio via the microphone in port
requires the sound card to use its A/D converter (analog to
digital). Some common digital audio formats include WAV files,
MP3, and Ogg Vorbis.
- Line in port – The line in
port on a sound card has the same physical characteristics as the
microphone in port (female 3.5mm mini jack) but the two ports are
used for two completely different types of sources. The microphone
in port is to be used with non-amplified sources. The line in port
is used to capture audio from amplified or powered sources such as
cassette players, digital audio tape (DAT) players, external CD
players, and other devices with line out options. This provides
users with the ability to capture their voices using a recording
application on the computer.
- Digital in port – With the
popularity of digital audio sources (such as CD, Minidisk, DVD,
and DAT players), sound card manufacturers are adding external
digital audio source capture components. Most digital in ports use
the SPDIF or Sony Phillips Digital Interface. SPDIF is outlined in
the "red book" audio standard for digital audio
recording. The digital in port on a sound card is usually one of
the following configurations:
- Toslink – a fiber-optic port
developed by Toshiba
- Coaxial – using an RCA jack
- Mini jack – a female 3.5mm port
physically the same as the microphone in and line in ports.
The major advantage of using the
digital in option is that there is no analog to digital conversion
necessary to capture the audio information. Digital audio capture
produces the closest possible reproduction available.
|
