MIDI and Synthesized Sound

1. MIDI and Synthesized
Sound
CGT 158

2. MIDI
Objectives:
• Understand the basics of the MIDI protocol
• Identify the two types of MIDI-compatible
tracks that Pro Tools provides
• Recognize the difference between sample-
based operation and tick-based operation
• Set the Main Time Scale to Bars|Beats
• Prepare a system to record MIDI data
• Set up a virtual instrument to play MIDI data
recorded on an Instrument track

3. MIDI Basics
 MIDI = Musical Instrument Digital Interface
 MIDI data is not audio
• Represents performance parameters (information about which
notes are played when)
• Does NOT represent sound waves
 Up to 16 channels of MIDI data can be sent through a single
MIDI cable or port
 MIDI sequencers work with MIDI data
• Store MIDI data
• Edit MIDI data
• Play back a MIDI performance through a synthesizer, sound
module, or drum machine

4. MIDI in Pro Tools (1)
Two types of MIDI-compatible tracks:
• MIDI tracks – Store and playback MIDI data only (no
audio)
• Instrument tracks – Store and playback MIDI data and
route audio signals for playback
Creating MIDI-Compatible Tracks
• Use New Tracks dialog box (Track > New)
• Select MIDI Track or Instrument Track
• For Instrument tracks, choose Mono or Stereo
• Track timebase will default to Ticks

5. MIDI in Pro Tools (2)
 Sample-Based Operation vs. Tick-Based Operation
• Sample-Based Operation
 Recorded information is tied to fixed points in time
 Sample-based locations are absolute locations in time
 Locations wont change if the session tempo is modified
• Tick-Based Operation
 Recorded information is tied to Bar|Beat locations
 Tick-based locations are relative locations in time
 Locations will move earlier if the session tempo increases and
later if the session tempo decreases
 Pro Tools subdivides bars and beats into ticks: 960 ticks = 1
quarter note

6. MIDI in Pro Tools (3)
 Time Scale and Rulers for Working with MIDI
• Setting the Timebase Ruler and Main Time Scale
 Display the Bars|Beats ruler (View > Rulers > Bars:Beats)
 Set the Main Time Scale to Bars|Beats:
• Click the head of the Bars|Beats ruler
• Select View > Main Counter > Bars:Beats
• Click the Main Counter Selector and select Bars|Beats
• Displaying the Tempo, Meter, and Key Signature Rulers
 View > Rulers > Tempo
 View > Rulers > Meter
 View > Rulers > Key Signature

7. Setting the Session Meter, Tempo, and Key (1)
 Setting the Session Meter
• Meter default = 4/4
• To change meter:
 Click the Add Meter Change button on
the Meter Ruler
 Enter a new meter in the Meter Change
dialog box at location 1|1|000
 Setting the Session Tempo
• Tempo default = 120 BPM
• To change tempo:
 Click the Add Tempo Change button on
the Tempo Ruler
 Enter a new BPM value in the Tempo
Change dialog box at location 1|1|000

8. Setting the Session Meter, Tempo, and Key (2)
 Setting the Session Key Signature
• Key signature default = C Major
• To change key:
 Click the Add Key Signature button on the Key Signature Ruler
 Select the mode (major or minor) and key in the Key Change dialog box at location
1|1|000

9. Preparing to Record MIDI (1)
 Connecting a MIDI Device
• MIDI Out to an input on a MIDI interface
- and -
• MIDI In to an output on a MIDI interface (optional)
- or -
• USB to a port on computer (MIDI input and output)
 Checking MIDI Inputs/Outputs
• MIDI Input selector:
 Determines what gets recorded to the track
 Set to All by default (all input from all connected MIDI devices)
• MIDI Output selector:
 Determines which device or port is used for monitoring MIDI playback

10. Preparing to Record MIDI (2)
 Record-Enabling MIDI-Compatible Tracks
• Click the track’s Record Enable button
 Setting Record Options
• MIDI Controls
 Available in the Transport window and Edit window
 Options include Wait for Note, Count Off, Metronome, MIDI Merge (disable for
initial recording), Tempo Ruler Enable, and Current Meter
• Input Quantize
 Automatically aligns recorded MIDI notes to a timing grid
 Event > Event Operations > Input Quantize

11. Using Virtual Instruments (1)
 Virtual Instruments = Software equivalents of outboard
synthesizers
 Placing a Virtual Instrument on an Instrument Track
• Display track inserts
• Click an insert and choose
Plug-In > Instrument >
desired instrument

12. Using Virtual Instruments (2)
 Using Xpand!2
• Xpand!2 = AIR Virtual Instrument installed with Pro Tools
• Provides four synthesizer slots/parts (A-D)
• Parts can be turned on/off using the part’s power indicator
Power Indicator
for Part A

13. Recording MIDI
 To Record:
• Verify track(s) is/are record-enabled
• Click the Record button in the Transport window
• Click Play
- or –
• If using Wait for Note, begin playing the MIDI controller
 To Play Back:
• Use a virtual instrument or outboard device
• Disable recording
• Click Play

14. Viewing MIDI Data on MIDI-Compatible Tracks (1)
Edit Window Track Views for MIDI and Instrument
Tracks
• MIDI Clips View
 Shows MIDI notes grouped together into clips
 Notes are visible but cannot be individually edited
• MIDI Notes View
 Shows individual notes in a
piano-roll format
 Pitch range can be scrolled up
and down using mini-keyboard
• Velocity View
 Shows the attack velocity of each note with velocity stalks

15. Viewing MIDI Data on MIDI-Compatible Tracks (2)
 MIDI Editor Window Views
• Can show MIDI data and automation data
• Can show all Auxiliary Input, Instrument, and MIDI tracks
• Can show automation and controller lanes
• Let you toggle between Notes view and Notation view