WHAT IS MIDI - Part 1

What is MIDI ?

Introduction

MIDI is an international standard which allows communication of musical performance by means of digital signals.

Without MIDI, the communication is limited and difficult. MIDI which is the international standard, enables the connections between the instruments of different manufacturers, and more, MIDI needs only one cable for the set up of two devices.

There are various kinds of MIDI devices on the market, such as synthesizer, sequencer *1, rhythm machine, etc.To make the best use of this useful MIDI, however, good comprehension of MIDI is required.

This manual will greatly help you if thoroughly read.

* 1 Sequencer
Equipment which records pitch and timing values sequentially, and makes synthesizers play automatically.

1 .Connections

The MIDI equipped instruments employ 5 pin DIN * 2 connectors which are indicated as "IN" "OUT" and "THRU" respectively.

"IN" is a connector for receiving a signal which contains MIDI messages from another MIDI instrument, and "OUT" is for transmitting messages.

The MIDI THRU output is provided to send a direct copy of data coming in MIDI IN.

*2 DIN
West Germany Industrial Standards. DIN Connectors include 5P (5-pin), 7P (7-pin), etc. with different numbers of pins.

In Fig 2, three MIDI synthesizers A, B and C are set up through MIDI Connectors.


If A is played, the performance messages of A will be sent through its MIDI OUT, and B, which receives the messages, will sound. C does not sound as it is connected to the MIDI OUT of B.

This is because the message fed into the MIDI IN is not sent out from MIDI OUT.

Therefore, when A is played, only A and B will output sounds.

If B is played, B's messages will be sent from the MIDI OUT, making the synthesizer C sound .

The C's MIDI THRU will send the direct copy of the messages fed into the MIDI IN, passing the performance messages to A as well.

So, playing B will make all A, B and C sound.

In other words, MIDI THRU can be used to send the messages to more than one device.

Theoretically speaking, as many MIDI devices can be connected using the MIDI THRU's, but to avoid delay of the messages use the MIDI THRU Box *3 for setup of more than three or four devices.(Fig 3)



If the synthesizer, C is played, the performance messages of C will not be sent out, as there is no MIDI cable connected to the C's MIDI OUT.

Playing C will make only C itself sound.

Some MIDI devices do not have MIDI THRU, and some do not have MIDI OUT.

This is because they are considered to be unnecessary.

Some MIDI keyboards and sequencers, even without MIDI THRU, can send the signal received at its MIDI IN directly to its MIDI OUT.

Some instruments can select MIDI OUT or MIDI THRU in the same MIDI Connector.

Please read the explanation on MIDI in the manual of each instrument.

* 3 MIDI THRU Box
This is what may be called Channelizer which can distribute messages to several MIDI devices. A MIDI connection cable should not be made forked cord, therefore, to send messages to several MIDI IN's, this unit can be effectively used.

WHAT IS MIDI - Part 1