MIDI and Controllers:
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Musical Instrument Digital Interface was defined in 1982 and over subsequent years revolutionized music production. MIDI is in fact a very simple concept it allows MIDI equipped devices to communicate with each other. Once MIDI interfaces were made available for computers, software was developed that records and plays back the MIDI data. Each MIDI buss can contain up to 16 channels of data.
MIDI data is digital information that includes functions such as:
- Play a certain note with a velocity value on a particilar channel.
- Choose a particular sound patch.
- Realtime controllers such as: Volume, Pan, Pitch bend and Modulation.
It is very important to understand that you cannot 'hear' MIDI, you can only hear the result of the data being read or processed by the receiving device. MIDI has no concept of sound or tone. MIDI can contain program change data for example 'select sound number 10 on MIDI channel 5' this will always select sound number 10 on whatever receiving device is used, it may be Electric Piano on one device but something else on a different device.
No realtime audio data travels down a MIDI cable, this is a basic mistake that people make. If you are driving a synthesizer by MIDI you have to listen to the result by connecting the audio output to the speakers, and to record audio you have to connect the audio output to the audio input of the audio interface.
MIDI sequencing is a very useful tool for the composer. MIDI data can be edited much more intricately than audio data. As mentioned previously, because MIDI has no concept of tone a track that was recorded using a piano sound can easily be changed to strings etc. MIDI data is easily transposed, quantized, and can play back at any tempo that the sequencer can produce.
MIDI data is used to control Virtual Instruments. As the use of VIs is expanding, many composers don't require hardware synthesizers any more. They input data into the computer via a MIDI controller. 'MIDI controller' or just 'controller' is a general term and can be applied to a range of devices:
- Keyboard controllers may have no internal sounds and connect to the computer via a MIDI interface or USB. These often have sliders, switches or rotary encoders included that interface with the software.
- Drum pads are sometimes used to enter rhythmic parts or to trigger drum loops in the software.
- Dedicated fader controllers can be assigned to a range of fuctions but are most commonly used to make volume and pan level adjustment. More elaborate versions have moving faders that replicate automated mix settings.
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