MIDI AT WORK

Back in the day, the concept of presetting a series of notes to play automatically was experimented with by electronic music pioneers like Don Buchla, and admired by Robert Moog (by the way, pronounced ‘m-OH-g’). Moog used a series of knobs and switches to alter the note’s pitch and length with generally 8, 16, 24 or 32 steps, called a SEQUENCER.

It produced a machine-like melody; think of the end of Emerson Lake and Palmer’s ‘Karn Evil 9 – 3^rd Impression’.  Here’s a cool example by a YouTube poster (click here). Very cool indeed, but it had its limitations. 

With the advent of MIDI, the same principles of Moog’s sequencer were used, except the actual performance on the keyboard could be ‘recorded’ into a sequence recorder’s memory for playback. I put ‘recorded’ in quotation marks because the actual sound isn’t recorded, but the same data of which keys were pressed, when, how long, how strongly, etc., etc. Only data was recorded. The sequencer could then be set to play back this data into the keyboards, and could make them do the same thing that the player did on them when ‘recording’ into the sequencer. This is much akin to the idea of the paper player piano roll of yore. The holes in the paper aren’t the sounds, but only the instructions for the piano when to strike the note and how long to hold it out. Therefore, sequencing is the modern equivalent to making your own virtual player piano rolls, without the paper.

The beauty of the MULTITIMBRAL keyboard and SEQUENCER combination is that you have a virtual recording studio at your fingertips. Essentially, the MULTITIMBRAL KEYBOARD is like having 16 different keyboards at your disposal, which means one can have 16 different sounds played simultaneously. Just like previous discussions of separate keyboards and different MIDI CHANNELS, the MULTITIMBRAL KEYBOARD has the ability to set up 16 different sounds, all driven by their own individual MIDI channel. The sequencer is capable of storing the performance of each of those separate parts onto separate tracks. Since it is not recording sound and only the performance, the player can decide to change what sound is used on any of those tracks later on if desired. (Try THAT with audio!!) A new MIDI term crops up here. Since we’re using the same keyboard to access 16 different sound parts, we need to make the physical keys separate from the synth’s sound generating section. When we touch the keyboard, it plays the sounds of the synth as we know, but we want to disengage this so we have control over only the part we want to work with at a time. This control is called LOCAL CONTROL. It can be set for ‘ON’, the normal way the keyboard works, or ‘OFF’, disengaging the keys from the sound making bits. This now allows us to set the transmit channel of the keys to the specific sound part we want to work on, whether it be the sounds of that very keyboard itself, or connected instruments, and record them into the sequencer. Once it’s recorded into the sequencer, the LOCAL setting is no longer relevant because the sequence is taking over the playback, managing what part plays what.

By following the path of MIDI in this diagram, we can see that the performance data from the controller passes into the sequencer where it is stored in memory. While that is happening, the signal passes out of the sequencer back into the controller, passes through the controller into a slave, thru the slave into the next slave and so on. Since the controller, in this case, is also generating sounds, a problematic phenomenon occurs. By touching a key on the controller, we make a sound and generate MIDI data at the same time. That data goes into the sequencer, back out of the sequencer and into the controller again, trying to replay the note. This is called MIDI FEEDBACK.  To avoid MIDI FEEDBACK, we should set the controller’s LOCAL CONTROL to OFF so the sequencer can do the job of playing the sounds.

Up to this point, I have been referring to REAL TIME sequencing. Real-time means exactly that, playing in REAL time. Sequencers can also record in a unique mode as well called STEP TIME, where the performer can enter one note (or chord) at a time, while determining what note pitch and value should be stored in a sequencial pattern. One of my favorite examples of a recording done mostly using STEP TIME sequencing is by Dave Stewart and Barbara Gaskin called Henry and James.

This diagram shows the typical setup of a sequencer-based MIDI studio. By setting different MIDI channels to each tone module and accessing them individually from the controller, recording each part separately into the sequencer, we can create virtually any style of music with any type of sound, depending on what gear you have at your disposal. Once you’ve figured out the nuts and bolts of how MIDI works, you can record away to your heart’s content. I feel it’s pretty important to have a good handle on what’s going on in the tech world portion before getting too involved working on music, because nothing is as frustrating as trying to put down a great idea when the gear is not cooperating. Certainly your creative flow will be stonewalled.

Although this particular entry refers to a hardware sequencer, the principles are identical when we replace it with a computer. Future entries here will deal with computer-based sequencing and recording, opening up an entire new world of music production.

Okay, go hook it all up, figure out what does what, do some experiments first, then dive right in!

MIDI IN USE

In quick review, last time we stated that MIDI is a system by which one device can control another through transmitting instructions through MIDI cables. Below is a typical keyboard setup:

If the lower keyboard is set to transmit on MIDI CHANNEL 1, and the other two keyboards are set to receive MIDI CHANNEL 1, you could conceivably play the CONTROLLER and hear itself AND the other two simultaneously, responding to every key depression as well as DAMPER PEDAL, MIDI VOLUME, PITCH BEND, MODULATION, and PROGRAM CHANGE. A variation of this would be to set the top keyboard to receive MIDI CHANNEL 2. This would allow for the player to combine the sounds of the lower two keyboards with the top one not combined. By switching the controller to transmit MIDI CHANNEL 2, the combined sounds of the controller with the top keyboard would be heard, freeing up the middle one. The MIDI information simply passes through the middle instrument to the top one. Only the keyboard with the matching channel number to the controller will be controlled. Another term associated with MIDI channels is “OMNI”. If the controller was set to “TRANSMIT OMNI”, any connected MIDI device would be controlled regardless of its set MIDI channel number. This also applies to MIDI RECEIVE OMNI, where any device set to this would be controlled regardless of what MIDI channel was controlling it.

This type of MIDI setup is most useful in a live performance situation, where combining the sounds of different instruments might be desired. Most keyboards of today are fully capable of combining sounds within the instrument itself without the need to connect it to another one. This is because the instruments of today are MULTI TIMBRAL, or can produce many sounds simultaneously. Most keyboards of today compare to a stack of 16 keyboards from back in the early days of MIDI. Still, Pro players like to have an arsenal of sounds that are typical of certain keyboards or their manufacturers. There are sounds that are distinctly Roland, as there are particular Yamaha sounds, Korg sounds, and so forth. Also, even within a manufacturers offering, there are different types of sound generating devices that produce sounds for a particular purpose. Early analog synthesizers have a fat, warm, powerful tone where digital synthesizers typically have edgier, crisp, glassy tones. Samplers allow us to play real-world recorded sounds from the keyboard while PCM based synths open up the world of realistic instruments like pianos, strings, horns and drums. Whatever sound you have in mind, there’s a synth for that. There will be more on the different synth flavors in the future.

THE MIDI TONE MODULE

If you don’t need the keys on a synthesizer, why carry around all that extra bulk and weight? By connecting two keyboards together, we’re able to play the sounds of the second one from the first one’s keys. Well, great. Let’s get rid of all those extra keys then. Enter the MIDI TONE MODULE. It’s a keyboard without the keyboard. Just the guts in a box, usually rack-mountable to keep them all neat and packed in a box. Just about every keyboard that has been produced is also available as a MIDI TONE MODULE. They save space, are easier to cart around and look very cool when all stacked and lit up. Consider this set up:

This diagram is nowhere to scale, as the rack-mounted modules are only a standard 19” across. The standard single rack space is only 1 ¾” high. Some modules are single space, some double and some triple. There are still some boutique rack gear pieces that are more, but up to 3 spaces is typical.

THE CONTROLLER KEYBOARD

The above setup has the same type of capabilities as the three keyboard setup, just without the keys. Many pro players choose a special type of keyboard to control many rack mounted synths. These are specifically called CONTROLLER KEYBOARDS, designed for use with MIDI devices. They generally do not produce any sound of their own, and have many functions to easily control the connected modules, layer multiple sounds on the keyboard, split different sounds across the keyboard, preset program changes and set up an entire bank of modules to the desired sounds with a single switch.

The CONTROLLER KEYBOARD is an infinitely useful tool when setting up a MIDI-based recording studio, whether it be a home project studio, or a full-fledged facility. For a big-league live show, it’s just the ticket to keep all of those sounds and modules organized into neat button presses. By the way, the controller above is the one I use, a Roland A-90. Unfortunately, they don’t make these anymore, but it’s been an amazingly handy tool for my purposes. It has an 88 key weighted keyboard, so playing piano sounds ‘feel’ as they should. When it comes to synth style of playing, I may use another one of my keyboards with the regular synthesizer action. It’s nice to have that flexibility. Controller keyboards come in all sizes, right down to a 25 note version, if that’s all you need, all the way up to the piano-style 88 key version above, with practically everything in between.

Next time, we’re going to move into the studio environment where things will begin to get a little more slick. Until then, play LOUD!

What MIDI is... A Primer.

MIDI (Musical Instrument Digital Interface) is a computer language. It's really just a set of digital instructions to tell another piece of music gear what to do. MIDI, unto itself, has nothing to do with the actual sound. It refers to the connection between your instrument, effect unit, drum machine, sound module, computer interface, or anything else with MIDI jacks on it. MIDI cables are used to connect these points. They are 5 pin round plugs with a detent for correct orientation.

 

MIDI Cable

The connections on the device are generally labeled "IN", "OUT" and "THRU". These connections are simply logical points that we use to connect an instrument you physically want to play (the 'controller') to the device you want to remotely control (the 'slave'). As we play the CONTROLLER, the signal created must go "OUT" of the controller, "IN"to the SLAVE so it can know what to do. The "THRU" connection passes the information along to the next connected slave's "IN" and so on. You can link as many MIDI devices as you have.

MIDI connections

Imagine your TV for a moment. Generally, it's connected to cable. How can this one wire carry 1000 different channels of programs to watch? That is mind boggling enough for me, but the TV itself (or actually the cable box) is able to choose which one of the channels you want to see by selecting that channel. MIDI operates similarly. Our CONTROLLER 'broadcasts' on any one of MIDI's 16 channels. In order for the SLAVE to respond to this information, it must be set to the same channel number.

Some people who had purchased keyboard gear from me in the past got all excited to connect MIDI jacks to other MIDI jacks in equipment they already had, only to find out nothing was working. Typically, I would soon receive a frantic phone call. Some of my past customers were under the impression that MIDI was the SOUND! It is not, so you must still connect the audio outputs of each keyboard and slave to an amplifier. MIDI only CONTROLS the devices...MIDI has no audio, only control information.

In its simplest form, connecting a keyboard's MIDI OUT to another keyboard's (or sound generating module's) MIDI IN, and matching the channel numbers, we can play the controlling keyboard and hear both the controlling keyboard AND the slave simultaneously. This was great for layering different sounds together, like the meat-and-potatoes piano/strings combination I used to use for the wedding band I played with years ago. At that time, keyboards weren't able to make several different sounds at the same time, so connecting two of them together through MIDI was the way to accomplish this.

So, if there's no actual sound going through these MIDI cables, what is? It's staggering how much varied information is actually pouring down these cables at speeds we perceive as instantaneous. In short, when a key is pressed on the controller, MIDI 'tells' the connected device to play that same key. At the same time, it's also telling the slave how hard to hit the note and how long to play the note until its release. Simple, right?

This is MIDI in action in its most basic terms. If we go to switch to a different sound setting on the controller, we will find that MIDI has sent a PROGRAM CHANGE command to the slave. There are 128 of these in MIDI. This causes confusion on many levels because we now have instruments with thousands of sounds in them. Rather than confuse the issue now (something to get into later), let's assume each keyboard has 128 sounds in them. Where the confusion lies is that all keyboards have different methods of listing out their individual sounds. Roland's famous 8 set method listed sound 1 as 1-1, or Set 1, sound 1. By the time we explored up to sound 9, Roland's 8 set system was calling it 2-1. Hopefully, you're getting the logic here. Roland's sound number 8-8 was really number 64. To get to the next set of 64 (if there were that many), there might be another level where you could access the next bank. Get the picture? Now, to throw a wrench into the works. Computers like to call the first number of anything counted with "0". Sometimes, we will see "PROGRAM CHANGE=0" on our keyboard or computer displays which actually means Sound Number 1. So, in tech terms, MIDI is capable of transmitting Program Changes "0-127"; another thing to be aware of if we are to begin looking at the actual computer data at some point. This was another phone call I used to get..."I keep setting my sound to #57-Trumpet and it keeps switching to #56-Orchestra Stab...What's wrong with it??"

Tons of other stuff can be transmitted through MIDI such as PITCH BENDING, MODULATION WHEEL, VOLUME, and much much more...that will be a topic for another time.

My advice is to get familiar with the MIDI menu of your instrument or device. How to change the channel numbers and other settings will be in that part of your instrument's setup. More advice? Connect stuff together and have fun with it. That's really the best way to learn what it can all do. Sometimes, people won't try things because they're afraid they will ruin something. Luckily, the only adverse reaction you'll get from your instruments is that they just won't do what you expect. Be sure your connections are correct and have some fun with combining sounds!

Welcome to 'The MIDI Doctor' Blog

Hi there...

I never did a blog before, so this should be interesting! My name is Jim, and I used to be the keyboard specialist at a pro music store many moons ago. Back then, I was referred to as 'The MIDI Doctor' because I helped lots of musicians learn to use MIDI technology when it was in its infancy, right up to computer based products we use today. I taught seminars on MIDI sequencing, digital recording, music composition and synthesizer programming. MIDI is much more amazing than many people realize. Too many people think of MIDI as the cheesy music that comes from their computer's sound card, although even that has come a long way since the earlier days.

I always come across musicians who have music gear and computers who are mystified by their interconnection. Back in the day, it was more complicated because there were many more pieces of music gear necessary to accomplish the job that one single instrument can today. I still have about a dozen or so sound generating devices floating around my basement studio. (Maybe I'll save them for a long time and they will become valuable as antiques!!)

If anyone out there needs advice on how their keyboards, modules, drum machines, sequencers, MIDI effects, computers and any other interconnectable gear, please ask!