FROM MIDI TO GARAGEBAND COMPUTER-BASED MUSIC CREATION. Thursday, March 21, 13

Transcription

1 FROM MIDI TO GARAGEBAND COMPUTER-BASED MUSIC CREATION

2 TERMS TO KNOW MIDI: Music Instrument Digital Interface WAVE/AIFF Sequencer Digital Analog

3 MIDI Created in 1983 Musical Instrument Digital Interface Allows computers and electronic instruments to converse Sends multiple messages A highly efficient means to convey information about sound Port is a standard 5-pin jack Computers require an interface to replicate those jacks

4 MIDI In MIDI Out MIDI Thru MIDI JACKS (DIN)

5 PLAY A NOTE... and A musician pushes down (and holds down) the middle C key on a keyboard. Not only does this sound a musical note, it also causes a MIDI Note-On message to be sent out of the keyboard's MIDI OUT jack. That message consists of 3 numeric values as shown above.

6 RELEASE A NOTE... The musician now releases that middle C key. Not only does this stop sounding the musical note, it also causes another message -- a MIDI Note-Off message -- to be sent out of the keyboard's MIDI OUT jack. That message consists of 3 numeric values as shown above. Note that one of the values is different than the Note-On message.

7 SHARE THE LOVE... A musician pushes down (and holds down) the middle C key on a keyboard. This causes a MIDI Note-On message to be sent out of the keyboard's MIDI OUT jack. That message is received by the second instrument which sounds its middle C in unison.

8 But MIDI is more than just "Note On" and "Note Off" messages. There are lots more messages. There's a message that tells an instrument to move its pitch wheel and by how much. There's a message that tells the instrument to press or release its sustain pedal. There's a message that tells the instrument to change its volume and by how much. There's a message that tells the instrument to change its patch (ie, maybe from an organ sound to a guitar sound). And of course, these are only a few of the many available messages in the MIDI command set. MIDI: MORE THAN ON/OFF Pitch wheel Sustain pedal Amplitude Patch (Sound generator)

9 Daisy Chaining... You can attach a MIDI cable from the second instrument's MIDI THRU to a third instrument's MIDI IN, and the second instrument will pass onto the third instrument those messages that the first instrument sent. Now, all 3 instruments can play in unison. You could add a fourth, fifth, sixth, etc, instrument. We call this "daisy-chaining" instruments.

10 But, daisy-chained instruments don't always have to play in unison either. Each can play its own, individual musical part even though all of the MIDI messages controlling those daisychained instruments pass through each instrument. How is this possible? There are 16 MIDI "channels". They all exist in that one run of MIDI cables that daisy-chain 2 or more instruments (and perhaps a computer) together. For example, that MIDI message for the middle C note can be sent on channel 1. Or, it can be sent on channel 2. Etc. CHANNELS... Allow more simultaneous sounds...

11 16 CHANNELS Channel 1:organ Channel 2: timpani Channel 3: piano Channel 4: ukelele etc... By assigning each different synthesizer a different channel to which it should respond, pressing middle-c would result in multiple instruments (actually timbres) generated from one controller!

12 ADVANTAGES TO MIDI Small file size Easily controls many instruments/sounds Sounds can be created to fit the artistic vision of the composer Control An hour-long midi sound could be simply articulated in fewer than 6 bytes of information. An hour-long WAVE file would be over 10 MB

13 BY THE WAY... 1 byte = 8 bits 1 kilobyte (K / Kb) = 1,024 bytes 1 megabyte (M / MB) = 1,048,576 bytes 1 gigabyte (G / GB) = 1,073,741,824 bytes

14 AND IN FILE TRANSFERS... 1 bit/byte 1 kb = 1,000 bits/bytes 1 MB = 1,000,000 bits/bytes

15 DISADVANTAGES TO MIDI Limited to electronic instruments Accuracy of digital sounds still behind acoustic

16 WAVE/AIFF FILES Near-exact replications of acoustic sounds Large file size (relative to MIDI)

17 SEQUENCERS... the best of both worlds Sequencers use MIDI and loops (pre-recorded musical excerpts) to build songs

18 GARAGEBAND Multiple-Track Sequencer Unlimited sounds Real and software instruments Exports to itunes Multiple tracks Unlimited sounds via JamPacks and many online loops Connected to a microphone or mixer allows recording (and later mixing) of live instruments