*********************************** AM/FM ***********************************  Howdy readers, Following the request from many faithful AM/FM readers to start a "Beginners' Guide to MIDI", one of my favourite AM/FM contributors and experienced MIDI user Kevan R. Craft has taken the job and written a whole series of articles especially for those who wants to learn MIDI, and wants to learn it properly! Kevan has written a very good series of articles - it is well written, easy to understand, deals with things in just the right order, and... well, to make it short, if you want to learn MIDI from scratch, then this is the place to do it! I don't know yet how many parts this series will have. At least 10, I should think. Today's "episode" is the first one, called "What is MIDI"? In the next issue of AM/FM, we will publish the second part, titled "The Benefits of MIDI", and so on. So enjoy yourselves, make sure you catch all the parts of this superb tutorial written especially for AM/FM by Kevan R. Craft Thanks for your splendid work, Kevan. [Ed]. *********************************** AM/FM ***********************************  ******************************** * MIDI *  * *  * A Basic Introduction *  ********************************    Written for AM/FM by Kevan R. Craft. ------------ 1. WHAT IS MIDI? ------------ (1) Conversation Between Musical Instruments ---------------------------------------- Musical instruments finally began "conversing" in the 1980's, a revolution in the world of music. Now, one instrument can say to another: "play middle C, with about 60 % strength, then play E4, a little louder". The second instrument "listens" to this dialogue, and plays the notes in turn , as long as it can understand the language used. The "language" that is now shared by all electronic musical instruments is called "MIDI". Even though the instruments can mow "converse", they still have no will of their own. In fact, the only link in the chain with its own is you the musican or user. Then the instruments interpret your performance by "translating" it into MIDI. "MIDI" is considered to be "the language which is used to send 'performance information' from one instrument to another". Although MIDI is a relatively new concept, it has already became a household word in the musical instrument scene. It is one of the common features for today's musical instruments. For your reference, MIDI stands for "Musical Instrument Digital Interface". (2) Applications of MIDI -------------------- MIDI is widely known as a "language between musical instruments". MIDI has expanded in such a short period of time, because it can be applied to many kinds of situations. MIDI is a universal term. Although there are many different languages in the world, such as English, Norwegian, German, and so on, MIDI has only one language, and can therefore provide communication between Japanese and American instruments, or Norweigian and German instruments. More importantly, MIDI can even be used to "talk" to instruments from different manufacturers. Furthermore,, MIDI can be applied to many kinds of instruments. In this way it is possible for an electronic piano to "talk" to a synthesizer, or a drum machine. Consequently, MIDI has enormous potential for growth and development, and in the 10 or 12 years since MIDI first has appeared , it has seen the emergence of computer technology and software exploitation of MIDI's possiblities. (3) What Makes MIDI Conversation Possible ------------------------------------- Just how is MIDI used to provide this conversation"? To explain, take a look at the back of your instrument, those without should enquire at a music instrument shop and ask to see. There should be several connectors, including a MIDI (IN), a MIDI (OUT) and often a MIDI (THRU) (it is advised to purchace a MIDI instrument with all three of these MIDI connectors otherwise you are restricting the possibility of expanding your MIDI set-up at a later date). These MIDI conections are the ears and mouth of the MIDI conversation, and are essential for any MIDI communication. The actual "MIDI conversation" travels from MIDI (OUT) of one instrument to the MIDI (IN) of another, by connecting only one MIDI cable between these two sockets. The cable used is three core, two cores are for the signals from the instrument and the third core is for screening or sheilding against interference and 'buzzing' noises, a kind of earthing if you will. The cable used has two male, five pin, din connectors at either end. NOTE: ---- "DIN" sockets look very similar to MIDI sockets, but have an entirely differnt fuction. "DIN"" sockets are to be found on the rear of Hi Fi stereo amplifiers, cassette tape machines etc and are the means of the input and output of sound which contains a small electrical signal charge, so please DO NOT connect a MIDI cable to a "DIN" socket! Back to MIDI, so why do we need three sockets? (MIDI IN, MIDI OUT, and MIDI THRU). MIDI IN is for "listening to a MIDI conversation, that is, it is the entrance for MIDI information. MIDI OUT is for "speaking", to send the conversation from an instrument, and is therefore the exit point for MIDI information. MIDI IN and MIDI OUT are relatively simple to understand and use, however, MIDI THRU is similar to MIDI OUT, in that is does "speak" to the next instrument, however, it doesn't provide its own conversation, it merely "repeats" anything heard by the MIDI IN. In a typical set-up, MIDI information is fed out of the MIDI OUT of keyboard number 1, and into the MIDI IN of keyboard number 2. It is also passed on to the MIDI IN of keyboard number 3, via the MIDI THRU of keyboard number 2. In this way, the information from keyboard number 1 can control both keyboards 2 and 3. (Keyboard number 1 can be a computer using a software sequencer program as and keyboard 2 may be a synthesizer and keyboard 3 may be a synthesizer module unit which makes the same sound as a keyboard but instead of playing any keys, because modules are just electronic boxes, the sounds are prompted to play by the MIDI information). Such a combination of more than 2 instruments is referred to as a "MIDI system". Of course, without the MIDI THRU this set-up could not become a MIDI system, and therefore it is easy to understand the use of MIDI THRU and the importance of purchasing a synthesizer with all three connections containing MIDI IN, MIDI OUT and MIDI THRU. (4) One-Way MIDI Conversation ------------------------- MIDI information is sent from MIDI OUT to MIDI IN, or from MIDI THRU to MIDI IN. The information is always sent one way, (generally) referred to as 'HANDSHAKING'), so that the "speaker" and the "listener" in a MIDI conversation remain the same, always! For example, a MIDI "keyboard controller" which has no keyboard of its own or a MIDI "sound module" which has no keyboard, and so on, has fixed roles. They are either the "Master", or the "slave". In this situation, the "speaker" is called the master and the "listener" is the slave. ( A computer can be the master and the keyboards and module will be the slaves - that's how it should be, the user is the master in control and the synths are the slaves, never forget that keyboards and modules are just machines, which you the master, control. Furthermore, the master/slave relationship is not always one to one, as previously discussed. the number of slaves can be increased, 1:2 or 1:3 and even 1:10 and so on. As a result even in very large MIDI systems if you check that the flow of information is all one-way, and correct, and the relationship between master and slaves is very clear, then the connections will pose no problem. (5) Closer is Better ---------------- From the previous discussion, it would seem that we could construct a chain of instruments, one after the other, via a large series of MIDI THRU connections. However, in reality, a MIDI conversation involves some complicated "dialogue", and too many THRU connections can distrupt the conversation , making it progressively easy to "understand". Consequently, the 4th or 5th instrument in the chain may receive incorrect data. To avoid this situation, place the master and slave instruments as close together as possible. This does not mean the actual physical placement, but rather the number of MIDI connections between them. To simplify this proceedure, a MIDI THRU box, or OUTPUT Selector should be used. MIDI THRU boxes send MIDI information from the master to the slaves at the same time, so that each slave recieves the information first hand (correctly). There are many kinds of MIDI devices, but remember, although perhaps the simplest, the through box is the most necessary when cmmunicating with more than 4 or 5 devices. K.R.C. 1992.