From the August 1989 issue of Radio And Production

The MIDI Page

Sequencer Basics

by Todd Albertson

Before I actually begin this month's article, let me take a moment to pass along a nice experience that recently happened to me. My partner and I were about to play for a club in the Detroit area, and we discovered that there were not enough channels available on our mixer for all the new equipment we bought recently. "No problem," I said. We'll just route these two units together through this direct box, and mix them down as one unit. WRONG! Big problem. It seems that anytime you put another unit together with the Kawaii K1 using anything less than FULLY isolated connectors, the second instrument will suffer a DRASTIC reduction in volume. Egad! With only two days left until the show, I was eager to get help on this one. I called Kawaii and soon came to grips with the fact that none of their product specialists had any idea as to why this would happen. The remarkable thing was that THEY realized this as well. Unlike E-MU, Roland, Korg, or virtually ANYONE else I have stumped with difficult questions or suggestions, these people DUG IN and decided that if they didn't know the answer, then by gosh, they would find one. I ended up chatting with THE CHIEF ENGINEER for the whole freakin' U.S. division. He went and got the schematics for the unit while I was on the phone and quickly spotted the fact that the K1 uses noise gates in its output stage that deliberately short to ground when the instrument is not producing sound, thus eliminating ALL NOISE. Nice trick, huh? I have to admit a certain admiration for such creative problem solving. He then quickly devised a simple, workable solution that increased the impedance on the outputs of the unit to get us through the gig UNTIL HE WOULD COME UP WITH SOMETHING BETTER AND CALL ME! The whole thing was done in less than fifteen minutes. Mind you, he knew nothing about this column or my association with Clean Sheets. To him, I was just a musician trying to get ready for a gig. This experience was so rare, so unusual, that I was moved to write it down for you. That's "Kawaii." Good company to deal with.

OK. On with the show. This month we take our first serious look at sequencers, their purpose, and their amazing editing capabilities.

Whenever you play a keyboard, the MIDI codes coming from that unit can be actually memorized by a computer. This is because the MIDI codes are really just BINARY codes familiar to all programmers. Of course there are conversions and such involved, but we'll skip all that for now. When MIDI codes are stored in order, with timing information, we say that we have saved a SEQUENCE of EVENTS in the memory of the machine. This sequence can then be added to, edited, and enhanced in a number of ways. The editing features of sequencers are what give them their power, reputations, and "personalities".

Sequencers can be either software based or "dedicated" (hardware based). Software based sequencers are programs for already existing computer systems. Some excellent software is available. "Composer/Performer","Dr. T", "Finale" and "Octave Plateau", are some of the most outstanding sequencers (in terms of features and performance) available today. The huge advantage of software based sequencers is obvious. You don't have to buy another computer to run it! Furthermore, upgrading to a new version of the software is usually no more complicated than inserting a new disk. On the other hand, if you have no computer to start with, you must buy an entire computer system to operate these sequencers. Also, sad to say, some companies actually still use ridiculous copy protection schemes that keep you from copying the software to your Hard Drive for greater speed and efficiency. Worse yet, some companies actually write hidden files onto your system when you install the sequencer, or maintain secret "counters" in the software that can actually cause you a lot of heartache later. If you buy a software based sequencer, make absolutely sure that there are NO copy protection schemes in the software you purchase, and then honor the copyright laws by using it on your system, and no others.

Dedicated sequencers tend to be faster to operate, more portable, and easier to understand. They are often configured for one handed operation, and are much more difficult to damage accidentally. They are nearly always the first choice for musicians that travel from one job to the next. The biggest problem with these sequencers is the companies that make them. Usually these companies are EXTREMELY proprietary about the inner workings of their sequencers. They are often openly hostile to the idea of saving work done on their sequencer to another machine. An example would be Roland's method of handling files on the original MC-500. The software authors had the MC-500 give the song files names that could not be transferred and saved on IBM type systems. Such paranoia inevitably leads to many complaints by the more sophisticated users, so Roland's new software now permits the use of "Data Disks", saving files that CAN be transferred to an IBM type computer thus allowing for hard disk storage. Unfortunately, Roland has yet to provide its users with any sort of direct interface on the MC-500 itself to speed such storage processes. Users must copy files from the floppies (in DOS) if they wish to save their work in this way. Still, it is an improvement, and Roland is actually better than most companies when it comes to such things. Korg REALL Y got tough! Their solution was to use the most obscure, non-standard format they could find (a two inch diskette) for their SQD-1. THAT ends it. NO ONE can get at their song data without the SQD-1 itself.

Sequencers are wonderful for anyone who is actually composing music or sound effects. They also speed up operations when working with samplers. Here's an example: Suppose you wanted to create a promo with "Puh, puh, pow, power, Power, Nhhhhn, Nhine, Nhine, Ninety Six FM!", on certain beats of some music. With a sequencer, this becomes child's play. Sequencers allow you to create, place and edit EVENTS nearly anywhere in the music you've created. Furthermore, with a SMPTE interface, you synchronize all of this with a tape recorder, thus allowing you to place EVENTS into music you did NOT create!

Well, that's enough rambling for this month. Next month we will begin a microscopic analysis of MIDI code itself. Over the next few months, we will be examining the actual BYTEs transmitted, and what information is carried in them. Once you have gleaned an understanding of these concepts, almost any MIDI operation is transparent in its function. This material can be rather difficult to understand, but I know you're up to it -- looking forward to typing at you! ◙