What Is Midi - Yamaha PortaTone PSR-S700 Owner's Manual

What is MIDI?

Put simply, MIDI is a data transfer standard that allows
easy and comprehensive control among electronic/digi-
tal music instruments and other devices. To get a better
idea of what MIDI does, let's first consider acoustic
instruments, such as a grand piano and a classical gui-
tar. With the piano, you strike a key, and a hammer
inside hits some strings and plays a note. With the gui-
tar, you directly pluck a string and the note sounds.
But how does a digital instrument go about playing a
note?
Acoustic guitar note
Digital instrument note pro-
production
duction
L
Based on playing information
from the keyboard, a sampled
Pluck a string and the
note stored in the tone generator
body resonates the
is played through the speakers.
sound.
As shown in the illustration above, in an electronic
instrument the sampled note (previously recorded note)
stored in the tone generator section (electronic circuit)
is played based on information received from the key-
board.
Now, let's examine what happens when we playback a
recording. When you play back a music CD (for exam-
ple, a solo piano recording), you're hearing the actual
sound (vibration in air) of the acoustic instrument. This
is called audio data, to distinguish it from MIDI data.
Recording and playing back the performance of an
acoustic instrument (audio data)
Recording Playback
In the above example, the actual acoustic sounds of the
pianist's performance are captured in the recording as
audio data, and this is recorded to CD. When you play
back that CD on your audio system, you can hear the
actual piano performance. The piano itself is not neces-
sary, since the recording contains the actual sounds of
the piano, and your speakers reproduce them.
Internal amp Internal amp
Tone generator
R
(Electric circuit)
Playing the key board
Recording and play back the performance of a digital
instrument (MIDI data)
Recording
Controller (keyboard, etc.)
n
In the case of digital instruments, the audio signals are sent
through output jacks (such as [AUX OUT]) on the instrument.
The "controller" and "tone generator" in the illustration
above are equivalent to the piano in our acoustic exam-
ple. Here, the player's performance on the keyboard is
captured as MIDI song data (see illustration below). In
order to record the audio performance on an acoustic
piano, special recording equipment is needed. How-
ever, since the PSR-S900/S700 features a built-in
sequencer that lets you record performance data, this
recording equipment is unnecessary. Instead, your digi-
tal instrument allows you to both record and play back
the data.
Tone generator
Sequencer
Keyboard performance (MIDI data)
However, we also need a sound source to produce the
audio, which eventually comes from your speakers. The
tone generator of the instrument fills this function. The
recorded performance is reproduced by the sequencer,
playing back the song data, using a tone generator
capable of accurately producing various instrument
sounds — including that of a piano. Looked at in
another way, the relation of the sequencer and the tone
generator is similar to that of the pianist and the piano
— one plays the other. Since digital instruments handle
playback data and the actual sounds independently, we
can hear our piano performance played by another
instrument, such as guitar or violin.
n
Even though it is a single musical instrument, the PSR-S900/S700
can be thought of as containing several electronic components: a
controller, a tone generator, and a sequencer.
PSR-S900/S700 Owner's Manual
What is MIDI
Playback
USB storage USB storage
device device
Tone Generator
Sequencer
201