4/5/06

A Simple Guide to Learn Sequencers - Part-4



Day 4
It is all about Tracks

Track is the most important component of a sequencer; 90% of operations performed on a sequencer refers to a track. Track is a container that stores various types of data and messages which can be manipulated. Let us peek into some data level details captured by a midi sequencer.

Note: Each note in general midi has been clearly named, meaning every note has a unique identity. Starting from the C0 the lowest sounding note and goes on up till C7. Middle C would be C4. The number part here denotes the octave. Every note is represented in this Note name + Octave number [of a piano] combination. Further for every note played, there are 2 vital elements attached to it, namely the length or the duration of the note [how long it was played] and the volume at which the note was played, the volume is called velocity. Velocity is arrived by capturing the finger pressure. When a keyboard can recognize the velocity and pressure applied by the player, we call it a touch sensitive keyboard such keyboards will spit velocity data along with each note played. Softer the hit – smaller the number, the maximum velocity is 127. Note: All number ranges in the sequencer are 0-127 only, why? Just Google for it; In short, Remember, a sequencer when capturing a note – it also captures its velocity, the start time and its end time in the bar.

Note is just one of the element a track can store, there are other elements, like Control changes, Patch Changes. What is a control change? Midi supports various controls like the Sustain pedal in a piano], Pan position [in a mixer] Pitch bend using a pitch bender. Sustain is how long the note needs to be sustained, this is generated usually by a foot pedal controller. Pan position, in a stereo where the sound would be place, 64 will put it in the middle, while 0 or 127 will be hard right /left pan respectively. There are many controllers out there today, a funky one would be the breath controller, using which we can add breathe effects to wind instruments; however the keyboard has to support it. Most of the higher end boards support various such funky controllers.

Another very important data metrics you will find in a track is the Pitch bend data. Modern keyboard have this controller built in, it can pitch bend a note. Sequencers can understand pitch bend data too. Long ago I have used pitch bend without the controller, how?, key-in data manually to simulate it. Not anymore though, pitch bender is a vital component for a keyboard.

Patch Changes, you can change the patch numbers on the keyboards by firing back midi message to the keyboard/salve. In fact today using midi we can do sound effect changes, arpeggios pattern changes, every other nook and corner of the keyboard can be manipulated with Midi, this does not stop only with keyboards, Effect processors, vocals processor support midi events can be controlled via sequencers.

When you dissect a track, you would see a combination of notes, controllers, Lengths etc. The sequencer power here is realized when? Remember all of these complex parameters can be edited and manipulated as numbers.

To summarize “Track” [in OOP terms]
A Track has following properties
1. Name – Alphanumeric
2. [forced] Midi channel – Number [1-16]
3. [forced] Port number – Number [1-127]
4. [forced] Velocity – Number [1-127]
5. [forced] Pan position – Number [0-64-127]
6. Key Transpose – Number [-127 - +127]
7. Mute – True or false
8. Archived or locked. - True of false

We can perform various actions on a Track - [methods in OOP terms]
1. Clone
2. Copy [input range]
3. Interpolate [input range]
4. Quantize [input range]
5. Record [input range]
6. Punch in [input range]
7. Delete
8. Paste
9. Transpose [input range]
10. Split notes

Next we will check out few global parameters of a sequencer.


All Rights Reserved (c) Srikanth Devarajan, Unauthorized copying or re-publishing of this article is prohibited, you have license to learn! And pass it on to others with the authors name intact. If you want to syndicate this, kindly contact me at srikanthD at gmail.

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