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D
6
ABOUT MIDI
"""'~w~
While it is not necessary thaI
you
under stand everything
about the
MIDI
standard,
it
is helpful
to be familiar
with some
of
the
main
points.
The
followmg
disc
ussion will
cover
these
main
points,
so that
yo
u can easily implement all of t he
features built
into
the Ibanez MIOI
Guitar
System.
The
MID
I
(Music
I Instrument Digital
Interface)
standard is a
multi -manufacturer information exchnge code
that
leiS
any·
one control a number of "slave
"
instruments from a
"master"
instrument
or
control
source.
Playing
a
note on the master
will, for example, cause
the
slave(s} to follow suit. Patch
es
can be changed, synths can be synchronized in song, just
about
any musical
event can be
described
in
MID!.
Once in
MIDI
form
,
the
musical event becomes a command from the
master
to the
slave(s).
MIDI
is
a
"serial"
interlace,
meaning
that
all inforamtion is
transmitted
over a single wire. Control information is tran
s-
mitted
from
the
MIDI
OUT
port of the
master
unit,
and the
slave(s)
receive
the information through
the M IDI IN port.
The
MIDI
THRU
ports on
slave
units can
be quite
useful.
These
ports
simply
"
repeat" the
information received at the
unit's
MIDI
IN port,
allowing other slave units to receive
the
same
control Signal.
Keep
in
mind that the MIDI OUT ports
on slave
units are
inactive
unless
the
slave unit operates as a master
unit
at
some
point.
The
MIDI
code provides up
to 16
separate channels to be
transmitted over
the
single. serial line (channels 1
through
16).
This
permits
certain inforamtion
to be
transmitted over
specific channels, tobe received
by
slave units
"
tuned
" to
the
specific
channels.
This
mUlti-channel
format
enables MIDI
to
accomodate monophonic
as
well as polyphonic
synthesizers.
MIDI provides four basic modes of information
transfer.
Both
the master and slave(s) units must
be
set to the same mode
for
accurate
inforamtion
transfer.
0
9
•
MOOE 1
-
Omni On
/
Poly
Here, M
IDI infor
mation maybe transmitted
and
received
over
any
ch
annel (the "omni on" part)
and each channel can
accomodate more than one
note at
a
time (the "poly" part)
Essentially, M IDI transmission is reduced to
single
channel,
polyphonic operation. For any MIDI synths, thiS
IS
the
" defau lt"
m
ode~
that is, when the
unit
is turned
on and not
prea ssigned to another mode, this
mode is chosen auto-
matically.
•
MODE
2
-
Omni On
/Mono
Aga in, informalion
is
transferred
over
all channels.
but only
one note is played at a lime
(the "mono"
part).
This mode is
used
for lead-line type sounds, where polyphoniC
teKtures
are
not
required.
•
MODE
3
-
Omni Off
/
Poly
In this
mode M
IDI inforamt
ion is transmitted
over specifically
assigned MIDI
channels,
and each slave
is
assigned to
"l
isten"
10
a
speci fic channel
(the "omnt off' part). Each
channel's inform ation is polyphonic, so
that each slave can
receive its own, polyphonic information
from a single MIDI
line.
•
MODE 4
-
Omni
Off/ Mono
Again,
MIDI
information is transmitted
over specifically
aSSigned
M IOI channels, but
channel information is now
monophonic
(one note at a
t
ime per channel). The
sl ave units
ca
n still
play polyphonically, by receiving
more than one
ch
annel
(for example, one channel per voice). In
thiS mode
each
voice of
a slave unit may be independently
controlled
Forexample,
each voi ce can have totally different sounds.
Or
one
voice may be "bent" (as when
a
guitar
string is
bent),
w
hi le the other voices (strings) remain at
pitch.
It should be noted here
that
t
he
MCI
MIDI
Controller selects
its transm
ission mode automatically.
depending on
the
feature
s
that
are called up. As a player, you
should be aware
of
w hich modes are used by the
MCl, and whether the
particular
syn th(s) you wish to use can
receive these modes.
The m
ode Information of the Me1 is
included in
the
next
section of this manual
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