Instruction Manual

49
Computers, Sound, and Music
Introduction
• Different parts of a piece can easily be assigned to any instrument you
can imagine
• The music contains information on notes, tempos, and key signatures
that makes it possible to display and edit the piece using standard
musical notation
The primary disadvantage of MIDI is that the quality of the sound a listener
hears will vary depending on the MIDI equipment the listener is using. For
example, MIDI usually sounds much better on an expensive synthesizer
than it does on an inexpensive sound card.
Next topic: Digital Audio.
Digital Audio
Digital audio (frequently referred to here as just “audio”) is a simple way to
record and play sounds of any type. It works like a tape recorder—you
record something, then later play it back. Digital audio stores the sound as a
long series of numbers. To record audio in SONAR, you have to have an
audio cable connecting the audio output of your electronic instrument to the
audio input on your sound card or audio hardware. If you’re recording
vocals or an acoustic instrument, you need to connect a microphone to the
audio input on your sound card or audio hardware.
Sound Waves
Sound waves are vibrations in the air. Sound waves are generated by
anything that vibrates; a vibrating object causes the air next to it to vibrate,
and the vibration is passed through the air in all directions. When the
vibrating air enters your ear, it makes your eardrum vibrate, and you hear a
sound. Likewise, if the vibrating air hits a microphone, it causes the
microphone to vibrate and send electrical signals to whatever it's connected
to.
These vibrations are very fast. The slowest vibration frequency you can
hear is about 20 vibrations per second, and the fastest is around 16,000 to
20,000 vibrations per second.
Recording Digital Audio
To record digital audio, your computer monitors the electrical signal
generated by a microphone, an electric guitar, or another source. At equal
intervals of time (for CD-quality sound, this means 44,100 times a second),
the computer measures and saves the strength of the electrical signal from
the microphone, on a scale from 0 to 65,535.