A Guide to MIDI. Part 1:

Oct 20 '00 (Updated Oct 22 '00)    Write an essay on this topic.




THE CONCISE GUIDE TO MIDI AND AUDIO SETUP WRITTEN BY MARK STARMER.
PART1: THE BASICS.

INTRODUCTION
I have been using MIDI equipment for a few years. In the past I have had a few problems, but after a lot of time and the completion of an Advanced Level Music Technology course, I now have the ability to setup a number of different MIDI devices and hope to share this knowledge with other people. I hope to have made this guide both informative and easy to follow, and I also hope to regularly update this article. Due to the fact that this guide covers both MIDI and Audio data I have decided to include in both the ‘Introduction to MIDI’ and ‘Home Recording Tips’ sections of Epinions.com. This is for the consumer’s convenience.

CONTENTS
PART 1.
1. What is MIDI?
2. Wiring Up
3. Typical Setup
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PART 2.
4. MIDI Devices & Studio Equipment
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PART 3.
5. Mixing
6. Recording
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PART 4.
A. Web Links
B. MIDI Messages
C. Glossary of terms

1. WHAT IS MIDI?

MIDI stands for Musical Instrumental Digital Interface and is the international standard for Musical instrument communication. It basically allows one device, such as a PC or sequencer to send information to another musical device (such as a sound module or keyboard). MIDI compatible instruments and other MIDI devices are connected to each other via standard MIDI cables, with 5-pin DIN plugs on either end, each MIDI cable can transmit up to 16 channels (or 16 different sounds). These 16 channels can be from one or more MIDI devices, some of which can only play one channel others can play multiple channels (known as multi-timberal). A MIDI device, which can play 16 channels, would be known as a 16 Part multi-timberal instrument.

Each event transmitted through MIDI cables is known as a MIDI message and is sent as a combination of numbers ranging from 0 to 127. For example there is one command for playing a note, and a separate one for terminating it (known as Note On and Note Off). Each command usually has three separate data items. For ‘Note On’, this would be the Note On command, followed by the Note pressed, followed by the velocity of which the note was pressed. The velocity is usually set to the volume of the note, and depends on how hard the musician pressed the key. This only works if the keyboard is velocity sensitive though, but can be assigned to other settings such as resonance (explained later).


2. WIRING UP

When wiring up a MIDI device to another, there are different possibilities to consider, some MIDI devices only have only a MIDI IN or a MIDI OUT and some have both IN/OUT and THRU. The MIDI IN is always connected to a MIDI OUT device and vice-versa. The MIDI THRU is used to connect external MIDI devices, but it is best not to use more than three as any more can result in a slight delay which will decrease the quality of the music, as modules will sound slightly out of time.

3. TYPICAL SETUPS

Here I shall describe how to connect various MIDI devices together.

3.1 A BASIC SETUP

A simple MIDI setup could be a control device (such as a keyboard) connected to a sound module. This would be accomplished by connecting a MIDI cable from the MIDI OUT on the keyboard to the MIDI IN on the sound module. If the keyboard is a mother/master keyboard (meaning it has no sound output) it should work automatically, although some need to set to MIDI mode (which can be found in the user manuals of most keyboards). If the controller is a ‘Control Synth’ (i.e. has sound output) then you need to turn off the ‘Local’ setting. This can be hard to find on many keyboards. If Local is set to on, the keyboard will play sound as well as the module when the keyboard is pressed. This is a common error, which is occurs a lot.

Below is a simple diagram of how a basic MIDI setup should be connected.

Keyboard MIDI OUT ---------------> Synth MIDI IN

3.2 ADDING A SEQUENCER

Most basic MIDI systems would usually be connected to a sequencing tool, whether it is a piece of software such as Stienbergs Cubase VST, running on a PC or a hardware sequencer like Yamaha’s QY700. I shall assume that the setup is using a computer. To use a MIDI device on a PC the first thing that you need is a MIDI interface, this should not be a problem as most sound cards come with one. The MIDI interface on a PC also doubles as a joystick port, so if you have a joystick, then you also have a MIDI interface. To connect to a MIDI device you also need a special cable, which can be purchased from most music stores and computer retailers.

The basic setup will include a control synth (or a keyboard to most people) such as Yamaha’s CS1x, A Synth Module like the Roland XV5080 and a PC running sequencing software (Cubase VST). As there is more than one device, a mixer is also required so that both outputs can be heard from the same output. I will be using a Soundcraft Sprit 16 channel mixer, but smaller mixers can also be used, the setup will require 4 mono (or 2 stereo) channels.

The keyboard MIDI OUT is connected to the PC’s MIDI in. A sequencer such as Cubase will be running as well, a sequencer is used to record your music, and allows for more then one instrument to be played at any given time. Sequencing will be explained in a future document.

Below is a diagram of the best way to connect a Keyboard and Module to your PC.
MIDI Setup

Keyboard MIDI OUT -----------> Computer MIDI IN
Computer MIDI OUT -----------> Synth MIDI IN
Synth MIDI THRU -------------> Keyboard MIDI IN

Audio Setup

Keyboard Output L/R ===============> Mixer CH1/2
Synth Output L/R =================> Mixer CH3/4
Mixer Output ====================> Speakers

Note. If you are new to MIDI, I would advise you not to read on, as this section covers how to setup a simple studio, with many different components. It requires some advanced techniques which will be covered in later chapters.

3.3 A COMPLEX SETUP

A more complicated setup would obviously include many more devices than just a Keyboard and Synth, and would usually include some sort of sequencing and recording devices. The setup which I shall describe, will include the following components:
-A Control Synth (Yamaha CS1x)
-2 channel Digital Effects Module (Lexicon MPX 500)
-Sequencer (Cubase VST, running on a PC with MIDI Interface 2xMIDI OUT, 1xMIDI IN)
-Sound Module (Roland XV-5080)
-16 Channel Mixer (Soundcraft Spirit 16:8:2)
-Power Amp
-Nearfield Monitors (Speakers)
-8 Track Tape Recorder (Fostex MD80)
-Live Vocals (SM-58 Mic)


This setup is a lot more complicated than the previous ones and incorporates techniques which will be explained in parts two and three of this guide. This setup uses both live and pre-recorded events and a combination of both MIDI and audio data. The 8 track tape recorder will be used to finalise the mix, techniques of how to do this will be explained later in part 3. For now just presume that it is used to equalise the volume levels. The power Amp is used to power the speakers, and should be kept away from the other equipment to avoid interference.

MIDI setup

Keyboard MIDI OUT ------------> Computer MIDI IN
Computer MIDI OUT1 ----------> Keyboard MIDI IN
Computer MIDI OUT2 ----------> Synth MIDI IN
Synth MIDI THRU ---------------> Effects Box MIDI IN

Audio setup

Keyboard OUT L/R ========> Mixer CH1/2
Synth OUT L/R ===========> Mixer CH3/4
Mixer Aux1 ==============> Effects Box CH1
Mixer Aux2 ==============> Effects Box CH2
Effects OUT1=============> Mixer CH5/6
Effects OUT2=============> Mixer CH7/8
Live Vocals -------------------------> Mixer CH9
Mixer MIXDOWN 1-8 =======> 8 Track Recorder
8 Track Return ============> Mixer MIXDOWN Return
Mixer OUT L/R ============> Power Amp IN L/R
Power Amp OUT L/R =======> Nearfield Monitors

The MIDI setup now looks pretty simple compared to the Audio Setup. The most confusing part of the setup are the Mixers Aux Outputs and the MIXDOWN input/output. I shall give a brief description of what they are used for here, although they will be covered in greater detail in later chapters.
The English made Soundcraft Spirit series are split up into three main sections. Here I will consider the 16:8:2. The Input section contains 16 different mono inputs (or 8 stereo pairs). Each pair can be routed to one of eight subgroups (the mixdown), which are then sent to a DAT (Digital Audio Tape) recorder, or in this case an 8 Track recorder. This can then be sent back to the mixer to sort out volume controls, and then gets sent out to the main mixer output. The Aux controls are on all Input channels of the mixer and can be assigned to different modules (in this case the Effects Box). This is then fed back to the mixer, and can be assigned to a separate channel.

Note. This setup should also include a compressor / Gater but for simplicity I have decided to leave this component out.

Part 2 should arrive shortly (within a week or so), so keep a look out. If you have any MIDI problems or comments on this don't hesitate to send me a message or email.

M. Starmer!


LAST UPDATE: 21/OCT/2000





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markstarmer
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