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From: antonello@promind.UUCP (Antonello Biancalana)
Newsgroups: comp.sys.amiga.audio
Subject: Re: Midi
Message-ID: <03030.AA03030@promind.UUCP>
Date: 12 Feb 91 16:22:50 GMT
Followup-To: comp.sys.amiga.audio
Organization: ProMIND - Software analysis and development - ITALY
Lines: 93

In article <89933@unix.cis.pitt.edu> mager@unix.cis.pitt.edu (Rainer V Mager) writes:

> Hi, I would greatly appreciate it if some one could send me a summary on
> what midi is, what it can do for you, what does a midi keyboard do, and
> how much one would be.  I'm into writing music and such on my Amiga 500,
> but up till now I've just used programs like SOnix and DMCS and I
> reached their limitations, please reply and you might want to make it
> public here since others may be interested, thanx

MIDI, that stands for Musical Instrument Digital Interface,  was
designed  as  a Hardware and Software standards to make possible
the informations exchange between different musical  instruments
(musical notes,  program changes, etc.) or other devices such as
sequencers, mixers, computers, etc.
The   MIDI   Hardware   operates   at   31250  bauds  (+/-  1%),
asynchronous, a start bit, 8 data bits and a stop bit.
The  connectors  used  in  MIDI are the DIN 5 pin,  but,  at the
present time, not all the pins are used.
There  are  three  connectors  used  in  MIDI  works and they're
labeled: MIDI IN, MIDI OUT and MIDI THRU.
All  the  MIDI  informations  are  sent  and  received  thru the
connectors "MIDI OUT" and "MIDI IN".
The  "MIDI  THRU" connector is used to re-send the signal of the
"MIDI IN" connector to another MIDI device.
Not  all  of  the  MIDI devices contain all the MIDI connectors,
some have only MIDI IN, some lack of the MIDI THRU connector.

MIDI messages are sent in one of the 16 channels.
There  are  five  types of MIDI messages that are divided in two
categories: Channel messages and System messages.

The Channel messages are:

 - Channel Voice
 - Channel Mode

The System messages are:

 - System Common
 - System Real-Time
 - System Exclusive

CHANNEL  VOICE  is  used  to control instrument's voices.  Voice
messages are  sent  over  the  Voice  channels.  these  messages
include the events:  Note on,  Note off,  program change,  pitch
wheel change, after touch and controller change.

CHANNEL MODE is used to  define  the  instrument's  response  to
voice  messages.  These  messages  are sent over an instrument's
Basic channel.  These messages include  the  events:  Reset  all
controllers,  local control,  all notes off,  omni off, omni on,
mono on, poly on.

SYSTEM COMMON are the system  messages  for  all  the  receivers
connected  to  the  MIDI  system  regardless  of channel.  These
messages include the  events:  MTCQF  (Midi  time  code  quarter
frame),  Song position pointer,  Song select,  Tune request, EOX
(End of exclusive).

SYSTEM REAL-TIME is used to synchronize all the devices  in  the
system  and  are  intended  for  all  clock-based  units.  These
messages include the  events:  Timing  clock,  Start,  Continue,
Stop, Active sensing, System reset.

SYSTEM  EXCLUSIVE is used to send data such as patch parameters,
sampler datas or sequencer memory bulk dump.  Every device (i.e.
every manufacturer) has its system exclusive messages,  that is,
if you send a system exclusive message on a synthesizer  of  the
manufacturer  "X"  will  does not work on the synthesizer of the
manufacturer "Y",  except for the  "universal  system  exclusive
codes".


The computer in MIDI is usually used as a sequencer and sometime
as editor librarian to program synthesizers.


I hope this will be useful to you.
Best regards
- Antonello



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 ___________________________________ _____________________________________ 
|                                   |                                     |
| Antonello Biancalana              | Music composition, Sound Synthesis, |
| ProMIND - Perugia, ITALY          | DSP and  computer music: these  are |
| Software analysis and development | my favourite wonders.               |
|___________________________________|_____________________________________|

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