Lecture slides for Pro Tools 101, Lesson 1

August 18, 2017 | Author: earthsled | Category: Sampling (Signal Processing), Hertz, Audio Engineering, Decibel, Waves
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Lecture slides for Pro Tools 101, An Introduction to Pro Tools 11 by Frank D. Cook - Lesson 1...


Chapter 1: Getting to Know Pro Tools

Topics... Brief history of Digidesign (Avid Audio) Modifier Keys & Special Characters Fundamentals of Digital Audio

What Is Pro Tools? The industry standard for music and post production Multi-track audio recording and editing Runs on a host computer (software-based) Hard-disk audio recording, graphical audio editing

Features of Pro Tools Audio MIDI Notation Mixing Post Production

The Story of Digidesign 1984 - Founded as Digidrums by Peter Gotcher and Evan Brooks. Later became Digidesign. 1989 - Digidesign launches the first digital audio workstation system, Sound Tools, for the Apple Macintosh. The company refers to it as "the first tapeless recording studio". 1991 - Digidesign releases the first Pro Tools multitrack system, marking a significant advance in digital audio. The system offered 4 tracks of recording and cost about $6000!

Evan Brooks & Peter Gotcher

The Story of Digidesign 2001 - Digidesign wins a Grammy award for Pro Tools. 2003 - Avid acquires Bomb Factory's extensive product catalog. These products are now included with Pro Tools systems. 2003 - Digidesign wins an Oscar award for their contribution to audio post production for film. 2004 - Avid acquires M-Audio, which now operates as a business unit of Digidesign.

The Story of Digidesign 2005 - Avid acquires Wizoo, which now operates as Digidesign Advanced Instrument Research Group (A.I.R.), but remains largely autonomous, operating out of Bremen, Germany. 2006 - Avid acquires Sibelius, the music software, in a deal worth over $23 million. 2010 - the Digidesign brand name is phased out, with Digidesign products now falling under the Avid product banner. 2011 – Digidesign becomes Avid Audio

Pro Tools Software Configurations Pro Tools SE Pro Tools MP 9 Pro Tools 10 Pro Tools HD 10

Pro Tools Hardware Configurations Pro Tools HD Series Interfaces Mbox family (3rd gen) Eleven Rack M-Audio Interfaces Third party hardware

Modifier Keys and Special Characters

Keyboard Commands

Pro Tools Incompatible ASCII Characters / slash

' apostrophe

\ backslash

< less-than symbol

: colon * asterisk ? question mark " quotation marks

> greater-than symbol | vertical line or pipe

Basics of Digital Audio

Sound Basics Sound is caused by vibrations Vibrating objects cause air molecules to vibrate at the same rate Humans hear vibrations as sound when the frequency is between 20 and 20,000 cycles per second

Waveform Vibrations from different objects create different "shapes" Each sound is complex - influenced by materials and surroundings The waveform gives each sound its unique character

Frequency The pitch of the sound Measured in cycles per second (CPS) or Hertz (Hz) 1 Hz is the same as 1 CPS 1,000 Hz = 1 kilohertz (kHz)

Frequency Humans hear frequencies between 20 Hz and 20 kHz Each time the frequency doubles, the pitch rises one octave Example - the note “A” has frequencies of: 110Hz, 220Hz, 440Hz, 880Hz, etc.

Frequency Humans hear frequencies between 20 Hz and 20 kHz

Amplitude The loudness or softness of a sound Dynamic range of hearing Measured in decibels (dB) Threshold of hearing = 0 dB Threshold of pain = 120 dB

Hearing Damage 88 dB ≈ 8 hours per day 91 dB ≈ 2 hours per day 94 dB ≈ 1 hour per day 97 dB ≈ 30 minutes per day 100 dB ≈ 15 minutes per day

Hearing Damage 103 dB ≈ 7.5 minutes per day 106 dB ≈ 3.75 minutes per day 109 dB ≈ 1.875 minutes per day 140 dB ≈ instantaneous hearing damage

Earplugs etymotic.com $13 Etymotic Research ETY-Plugs ER-20

Amplitude Humans perceive a doubling of loudness with an increase 10 dB (approximately) The decibel is a logarithmic ratio (non-linear)


Analog Audio Sound is vibrations in air pressure A microphone translates the vibrations in air pressure into an electric signal (with waveform, frequency, and amplitude) This signal is analogous to the original vibrations in pressure

Analog Audio The electrical signal can be captured on magnetic tape The signals on tape can be played back through an amplifier and loudspeaker The speaker translates the electrical waveform into vibrations in the air

Analog to Digital Conversion

Analog to Digital Conversion Film captures light at 24 frames per second Sound must be captured 40,000 times per second (minimum) A digital “snapshot” of an audio signal is called a sample

Sample Rate

Sample Rate Harry Nyquist (1889-1976)... For digital audio, a sound must be sampled at twice its highest frequency A lower sampling frequency will produce strange overtones known as alias tones

Sample Rate Frequency range of human hearing = 20 Hz to 20 kHz Full-frequency audio requires a 40 kHz sample rate (at least) CDs use 44.1 kHz DV tape uses 48 kHz

Sample Rate Sample rate determines the highest frequency a digital system can accurately capture.

Dynamic Range

Dynamic Range Full dynamic range of human hearing is 0dB to 120dB CDs have a dynamic range of 96dB Popular music typically has a dynamic range of 6 to 10 dB, with some forms of music having as little as 1 dB or as much as 15 dB

Quantization Loudness is captured using quantization Each sample is quantified (assigned) to the closest amplitude value Computers use binary digits called bits (zero or one) A set of bits is a binary word

Bit Depth Bit Depth = Binary Word Length = Resolution A binary word with 4 bits can have 16 possible values (2 to the 4th) 16 bits = 65,536 possible values (2 to the 16th) 24 bits = 16,777,216 possible values (2 to the 24th)

Bit Depth Bit Depth determines the dynamic range a digital system can accurately capture.

Bit Depth & Dynamic Range More bits = more accurate quantization More accurate quantization = less noise Less noise = more usable dynamic range

Bit Depth & Dynamic Range 6 x bit depth ≈ Dynamic range (dB) 8 bits = 48 dB dynamic range 16 bits = 96 dB dynamic range 24 bits = 144 dB dynamic range 32 bits = 192 dB dynamic range

8-bit example

Review Frequency, loudness, waveform? Human hearing - frequency range? Human hearing - dynamic range? Nyquist? Bit depth -- dynamic range?

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