The MIDI Page: The Hardware

by Todd Albertson

Welcome back to the MIDI page! If you have been trying to follow all the technical stuff in this column for the last three months, you are probably wondering if it EVER gets any simpler. I have great news for you, it does! We have been delving into the basic elements of synth programming, which is by nature a difficult subject. Now, we are going to explore MIDI itself.
MIDI is an acronym standing for Musical Instrument Digital Interface. This is a fancy way of saying that keyboards, computers, synthesizers and several other pieces of equipment share a common language that allows them to "talk" to one another. Today, we will begin to see how you, as the adept producer, can set this up.

Let's start by considering the hardware. On the synth you are using, you should see the MIDI ports. These are the little, round, five pin DIN connector holes you will find on the back of nearly any synth made since the early eighties. If you are lucky, you will have three ports on each instrument; if not, only two. There are three possible labels for these: IN, OUT, and THRU.

MIDI IN ports are fairly straightforward. The computer codes controlling the instrument are input here. That is the only function it performs.

MIDI THRU is also pretty simple. Whatever is input into MIDI IN will appear in the THRU port about 3 4 milliseconds later. The instrument passes the data THRU. This does not mean the instrument does not react to the data, nor does it mean the instrument does react to the data; That is determined by other factors which we will discuss later in this article. Think of the THRU port as a kind of Xerox machine. It copies data, and passes it on for you to send to another instrument. Like a Xerox machine, it does not CREATE anything, it just copies. MIDI THRU does not transmit data ORIGINATING from the synth.

MIDI OUT is sometimes confused with MIDI THRU. Why? Beats me...there is nothing similar about them! If the MIDI THRU port is a Xerox machine, the MIDI OUT is an IBM Selectric typewriter. MIDI OUT sends data that ORIGINATES from the sending unit only. It does not pass information received from other units. Keep this straight or you may end up with "data loops" in your system that could damage something!!!

Having looked at the ins and outs of this thing, let's connect it up to something! To do this, you will need a MIDI patch cord. The best ones I know of are the "MIDI PLUS" cables made by a little company in Kalamazoo, MI, called "Pro Co Sound." It is important to get the kind of cable that can be opened and examined, and equally important for you to get a little screw-driver, open it, and examine it. I cannot (for legal reasons) mention the name of the company, but there is a well known cable manufacturer that would sell far fewer cables if people only took the time to look inside the DIN connectors and examine the solder connections. This excludes all the molded plastic ends, and for good reason. These ridiculous things may work for awhile, but when they quit, you must go out and purchase the metal tips to fix them anyway! What is worse, it will cost you more than if you would have just bought the metal ended cables in the first place, and you will be stuck with the still inferior wire that is usually attached to molded plastic tips. If it seems like I am making a big deal out of cables, remember this is DATA TRANSMISSION we are talking about, NOT audio. This is a much more critical application, and if you don't want junk data entering your synth, SPEND THE MONEY to get good cables.

Soooo... (the ankle bone's connected the foot bone), connect one end of your cable to the MIDI OUT of your synth (Synth 1), and the other end to the MIDI IN of another synth (Synth 2). Find the OMNI parameter (or switch) on Synth 2, and turn it ON. Walk over to Synth 1 and start playing. Surprise! BOTH instruments respond!!! This is called "layering" the instruments, and this has been used on almost every record you have heard in the last 5 8 years. Experiment with this, and I'll tell you more next time. Have fun!