4. Standard Controls

Many master keyboards allow the player to do a great deal more than simply play notes. MIDI connections carry many different control signals used to manipulate sounds and to affect the programming of sound modules and other devices. Let’s take a look at the most important types of control data along with the keyboard features usually associated with them:

Velocity

Along with pitch, one of the most important pieces of data accompanying every MIDI note is its ‘velocity’. This tells the instrument receiving the data how hard each note has been struck. It is vital to the realism of most sampled acoustic sounds like those from a piano and also to the expressive possibilities for many synth sounds. Where it is not relevant, the instruction is simply ignored – for example, a realistic organ sound does not respond to velocity data. In the past, the cheapest keyboards were not velocity sensitive at all, so velocity sensitivity was advertised as a selling point. Now though all but a few keyboards have it, so the fact is often not even mentioned.

Many master keyboards feature a number of selectable ‘velocity curves’. These affect the relationship between the physical force with which a note is played, and the number used to represent it in data. In simple terms, this makes a sound more or less responsive to physical forces.

‘Velocity’ refers by default to ‘note-on’ velocity – the force with which a key is pressed. Its logical counterpart is ‘note-off’ velocity – the speed at which it is released. Not all keyboards implement this instruction, and most sounds do not respond to it.

Pitch Bend

This control allows notes to be bent up or down in pitch as they sound and is usually controlled by a pitch wheel placed directly to the left of the keyboard. As pitch bend is generally only appropriate for monophonic lines the wheel usually springs back to its centre position (no bend) when released. The actual pitch range depends on the sound in use (often +/- one semitone, one tone or one octave).

Modulation

The modulation or ‘mod’ wheel is usually found next to the pitch wheel and is commonly physically identical, except that it generally retains its position when released. ‘Modulation’ is a somewhat vague term in this context - the mod wheel usually adds some sort of effect such as vibrato or tremolo, but can also be used to control other parameters such as filter cut-off frequency and the balance between discrete components within a sound.

Aftertouch (Pressure)

This control allows the player to affect some aspect of the note while they key is pressed, usually vibrato or tremolo, giving the player much freer control of these techniques than can be achieved by using the mod wheel. By continuously varying finger pressure, expression is literally ‘squeezed’ from the note in a manner similar to that used when playing a stringed instrument with vibrato.

Unless otherwise stated, this is almost always monophonic aftertouch - pressure applied to any key affects all notes being played. Polyphonic aftertouch is relatively rare and is often used as a yardstick by which the most advanced keyboards are marketed. Polyphonic aftertouch allows individual keys to send their own independent aftertouch data, however this is ignored by most MIDI instruments.

Pedals

Most keyboards have a sustain pedal connection. Pressing the pedal results in a MIDI signal, causing notes to sustain after keys have been released. This is important for realistic piano sounds, but may also be used to create crescendo effects as the number of sounding voices increases.

More advanced master keyboards usually incorporate a number of other pedal connections including the other two grand piano pedals (una corda/damper and sostenuto), as well as volume pedals and switch pedals which may be used for various functions including patch/program change (see below).

Control Knobs

Many sound modules and software instruments respond to a range of MIDI controls beyond simple pitch bend and modulation. These include filter and envelope parameters, oscillator frequencies, balance between components within a sound and just about anything else you can think of. Dedicated controller hardware does exist, but many master keyboards also include a dozen or more knobs and sliders for this purpose.

Program/Bank Change/Presets

Most MIDI sound sources respond to program/bank change messages. This allows sounds to be changed remotely, either directly by number or via up/down messages. More advanced implementations of this idea allow the controller to store presets so that the sounds required for a particular gig can be easily accessed in order, even though they may not have adjacent program numbers on the sound module, or indeed come from completely separate modules.

Split/Zone Functions

Most controller keyboards have a simple split function, allowing the top and bottom halves of the keyboard to send their data on separate MIDI channels, for example to allow playing strings with the right hand and piano with the left. ‘Zones’ offer a more sophisticated version of this idea - typically all zones may be defined independently. For example, Zone 1 may be made to cover the entire keyboard sending on Channel 1, while Zone 2 adds strings above middle C on Channel 2, and Zone 3 is assigned to only one note and triggers a gong sound on Channel 3 – intoxicating power!

Octave/Transpose

The transpose function allows the player to transpose the note data sent by a given number of semitones (very useful when a singer asks you to ‘take it up a third’). Octave buttons simply transpose the range in steps of one octave. This permits access to notes beyond the keyboard’s physical range, and is particularly useful on smaller keyboards.

How do I connect my Master Keyboard to my MIDI equipment?

Normally the MIDI Out of the keyboard is connected directly to the MIDI In on the MIDI interface and the MIDI In connectors of the individual samplers are connected to the MIDI Outs of the interface. In this case the sequencing program takes care of the data transfer to the sampler, with the advantage being that you can set the MIDI channel, octave position and dynamics directly in the program.

I've connected my MIDI Keyboard to the computer but don't hear anything. What am I doing wrong?

First, check if any MIDI data is present at the MIDI In connector of the MIDI interface (most sequencing programs provide a display, if necessary, you can also start recording and check your program's Event Editor for notes being recorded). If this isn't the problem, then check if the MIDI Out connection of the master keyboard is correctly connected to the MIDI In interface and that the MIDI interace is correctly installed.

When data enters the sequencing program it needs the ''MIDI thru function'' in your sequencer to transfer the notes in real time over the MIDI out port to the connected sampler or internally to the sound card. This function has to be on! You can usually set which MIDI channel you want to control by changing the MIDI channel of the currently selected track. Similarly, you can also transpose via the sequencing program or change the touch dynamics.

Why is my master keyboard only working when my computer is turned on and the sequencing program is running?

Since your master keyboard is not connected directly to the sampler(s), only via the MIDI interface, your sequencing program is needed to transfer the played notes to it or the built-in sound card. Many MIDI interfaces offer the option of transferring the MIDI data directly when the computer is off if they don't do it automatically. For others though you will need a MIDI adapter (just connect MIDI In to the interface via the adapter with MIDI Out).

Why do sounds still come from my synthesizer when I use it as a MIDI keyboard?

If you would like to use the built in sounds of your synthesizer or the sounds from another sampling device (sound modules, sound card etc.) in your sequencing program, then you need to set your synthesizer to ''Local: Off'' mode. This function is normally located in the basic settings of your synthesizer (where you can also find the MIDI send channel). In ''Local: Off'' mode, pressing the keys produces no sound but the notes will be transfered like normal over the MIDI Out port to the connected equipment (probably the interface in this case). However, signals at the MIDI input of the synthesizer are played back normally.

If the function ''MIDI Thru'' is active in your sequencing program then the data will be automatically trasnferred to the connected sampler, sound card or to your synthesizer. You can then set the output or the MIDI channel and choose which notes are transferred to your sequencing program, and your synthesizer will only play them once the data is sent back to it.

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