Roland HP 1700L - MIDI Concepts and Connections

® Using MIDI
About MIDI
MIDI (pronounced “middy”) stands for Musical Instrument
Digital Interface. MIDI is a world-wide standard that allows
musical instruments and computers to exchange musical
data. Most electronic musical instruments sold today are
MIDI compatible. MIDI-compatible devices have MIDI con-
nectors which can be connected to each other using MIDI
cables. MIDI does not transmit the sound of an instrument,
but rather "messages" in digital form that tell the receiving
instrument to "do something". These are known as "MIDI
messages".
MIDI can be used to do a variety of things.
@ Play the sounds of the HP-1700L/1700/900L/900 from other
MIDI instruments.
@ Play the HP-1700L/1700/900L/900 keyboard to make other
MIDI instruments or sound modules (*1) produce sound.
€ Record your performance on the HP-1700L/1700/900L/900
into a sequencer (*2), and then playback the recording to
make the HP-1700L/1700/900L/900 produce sound.
(*1) A sound module is a synthesizer or digital piano without a
keyboard; ie., a box containing only sound-producing circuitry.
Sound modules produce sound in response to incoming MIDI
messages. The Roland SC-33 is an example of a sound module.
(*2) A sequencer is a device that records MIDI messages and
plays them back to make MIDI instruments produce sound.
Sequencers allow you to edit the recorded MIDI messages in
many ways, and also let you control many MIDI instruments
simultaneously to create a MIDI orchestra. The Roland PR-1
Player & Recorder and MC-50 Micro Composer are examples of
sequencers. The MT-200 is a combination of a sound module and
à sequencer.
MIDI connectors
Look at the rear panel of your piano. The three MIDI connectors
are used to connect the HP-1700L/1700/900L/900 to other MIDI
equipment. Each connector has the following function:
MIDI
Out
THRU N
MIDI IN
This connector is like an ear that listens to incoming messages (MIDI
messages).
MIDI OUT
This connector is like a mouth that sends messages (MIDI messages)
to other devices.
MIDI THRU
MIDI messages received at MIDI IN are re-transmitted by this con-
nector. (This connector does not transmit messages that originate in-
side the unit itself.)
MIDI connectors accept a standard connector known as "5-pin
DIN". You may occasionally see similar connectors on other
devices, but be sure to use only cables that are intended
especially for MIDI (MSC-15/25/50, sold separately).
MIDI connections
In this example we use a MIDI cable to connect two digital
pianos, A and B.
In this setup, playing the keyboard of A will cause the sound
of B to be kenra in unison with the sound of A. This is be-
cause when you play the note “C” on keyboard A, a message
is sent from A to B saying “play the note C at such-and-such
a loudness and hold the note until commanded to release
it". (This is called a Note message.) B receives this message,
and plays (and releases) the appropriate note with the
appropriate loudness and timing.
Master and slave
When MIDI devices are connected, the device that sends the
message saying “do this” is called the “master” (the transmit-
ter), and the device that responds to this message is called
the “slave” (the receiver).
Since MIDI messages are always transmitted in one direction
over a single cable, you will need to connect an additional
MIDI cable from the output of B to the input of A if you want
A and B to respond to each other.
MIDI THRU connector
When transmitting the same MIDI messages to two or more
slaves, use the MIDI THRU connectors.
MIDI
iN
MID! MIDI
OuT THRU
LERRA
MIDI channels
Simply connecting a MIDI cable is not always enough to es-
tablish communication. MIDI messages are transmitted on a
"channel" (MIDI channel) of 1 - 16, and will be received only
if the channels of the transmitter and receiver match.
A single MIDI cable is able to carry messages of all 16 chan-
nels simultaneously.
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