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OPL2

OPL2, short for Operator Type-L 2, is a Yamaha FM synthesis sound chip released in the late 1980s. Implemented as the YM3812, it became widely known for its use in PC sound hardware such as the AdLib card and the Sound Blaster Pro. As part of Yamaha’s OPL family, OPL2 uses frequency modulation to generate timbres with relatively simple hardware and cost.

Architecture and sound generation: OPL2 provides nine independent voice channels, each consisting of two operators, for

Interface and control: The device is controlled via a register-based interface with an address port and a

Legacy and influence: OPL2 was the default FM synthesis engine on many 1980s PC sound cards, contributing

a
total
of
18
operators.
Each
channel
can
be
configured
with
different
operator
pair
connections
(algorithms)
to
shape
timbre.
The
operators
can
function
as
modulators
and
carriers,
allowing
a
range
of
sounds
from
basic
tones
to
more
complex,
harmonically
rich
textures.
The
chip
relies
on
a
fixed
register
set
to
control
parameters
such
as
frequency
numbers,
envelope
characteristics,
and
output
levels,
enabling
real-time
playback
suitable
for
music
and
game
sound.
data
port.
Software
writes
to
select
a
particular
register
and
then
to
set
its
value,
configuring
operator
properties,
channel
parameters,
and
note
on/off
events.
This
simple
I/O
model
made
the
YM3812
practical
for
integration
into
affordable
sound
cards
and
widely
supported
by
drivers
and
software
of
the
era.
to
the
distinctive
sound
of
early
PC
game
music.
It
is
widely
emulated
in
software
and
hardware
today
and
is
often
referenced
in
discussions
of
early
FM
synthesis.
OPL3,
the
successor,
expanded
capabilities
with
more
channels
and
enhanced
stereo
processing.