1/18/2019 18 January 2018 History and Future of Audio Signal Processing ELEC-E5620 - Audio Signal Processing, Lecture #1 Vesa Välimäki Acoustics Lab, Dept. Signal Processing and Acoustics, Aalto University Course Schedule for 2019 (Periods III-VI) 0. General issues (Vesa & Benoit) 11.1.2019 1. History and future of audio DSP (Vesa) 18.1.2019 2. Digital filters in audio (Vesa) 25.1.2019 3. Audio filter design (Vesa) 1.2.2019 4. Analysis of audio signals (Vesa) 8.2.2019 5. Audio effects processing (Benoit) 15.2.2019 * No lecture (Evaluation week for Period III) 22.2.2019 6. Synthesis of audio signals (Fabian) 1.3.2019 7. Reverberation and 3-D sound (Benoit) 8.3.2019 8. Physics-based sound synthesis (Vesa) 15.3.2019 9. Sampling rate conversion (Vesa) 22.3.2019 10. Audio coding (Vesa) 29.3.2019 Vesa Välimäki January 18, 2019 2 1 1/18/2019 Demo Grading • Presentation (60%): Communication and accessibility, sound examples, visualization and animations, creativity, slides • Report (40%): Readability, code quality, results, complexity, figures, references Benoit Alary & Vesa Välimäki January 18, 2019 3 Outline • The most important events in the history of DSP and its applications to audio, acoustics, and music • Publications • Inventions • Products • Standards • Some predictions of the future January 18, 2019 Vesa Välimäki 4 2 1/18/2019 Old Times • Alexander Graham Bell, , 1876 • Elisha Gray, ‘musical telegraph’, 1876 • T. A. Edison, , 1877- • Thaddeus Cahill, telharmonium, 1897...1906 • US commissioner of patents (1899): “Everything that can be invented has been invented” • Lee De Forest, triode vacuum tube ( ), 1906 • Leon Theremin, theremin, 1919 • Rice & Kellogg, dynamic , 1925 • Talking movies, 1925 • Laurens Hammond, electric organ, 1929...1935 January 18, 2019 Vesa Välimäki 5 Phonograph • Invented by Edison in 1877 • Birth of sound recording • Storage of sound as a mechanical waveform Source: http://www.americaslibrary.gov/page s/aa_edison_phonograph_1.html January 18, 2019 Vesa Välimäki 6 3 1/18/2019 Theremin • Air violin based on two antennas • Amplitude and frequency control • Heard on soundtracks of old sci-fi films and in pop music January 18, 2019 Vesa Välimäki 7 1948: Birth of Signal Processing • Claude Shannon, “A mathematical theory of communication,” Bell System Tech. Journal, 1948 • Oliver, Pierce & Shannon, “The philosophy of PCM,” 1948 (PCM = Pulse Code Modulation) • Richard W. Hamming, error-correcting codes, 1948 • Bell Telephone Lab: transistor, 1948 • Pierre Schaeffer: musique concrète, 1948 • Two professional societies were founded: IRE Audio Group was founded by Leo Beranek & others (since 1963: IEEE Signal Processing Society) Audio Engineering Society was founded in 1948 January 18, 2019 Vesa Välimäki 8 4 1/18/2019 1950s • Ragazzini & Zadeh: the Z transform, 1952 • Texas Instruments: development of a digital processor for seismic data, 1956 • First graphic equalizer: Langevin Model EQ-251A • Electric guitars: Fender Telecaster, 1950; Stratocaster 1954 • Stereo recording, 1956 • Sony: small transistor radio TR-63, 1957 • Max Mathews: computer music experiments, 1957- • Stereo LP record, 1958 • Koss Corporation: Headphones (“stereophones”), 1958 • Kilby, Noyce: integrated circuit, 1959 January 18, 2019 Vesa Välimäki 9 Sony TR-63 Transistor Radio • An early “pocketable” transistor radio • Popular in the late 1950s • Birth of personal electronics! • Pocket calculator • Walkman • Mobile phone •MP3 player •PDA • Tablet computer •etc. http://www.geocities.com/SoHo/Atrium/1031/trans/cool/Sonys.html January 18, 2019 Vesa Välimäki 10 5 1/18/2019 1960s: Early DSP Algorithms • Manfred Schroeder: digital reverberation, 1961 • Atal & Schroeder: 3-D sound with 2 loudspeakers, 1962 • Moog: , 1964 • James Cooley & John Tukey: , 1965 • J. Flanagan & R. Golden: phase vocoder, 1965 • The first DSP text book by Gold & Rader, 1969 January 18, 2019 Vesa Välimäki 11 3D Sound Using a Loudspeaker Pair Patent by Schroeder & Atal, 1963 • Hear sound from any direction with just two speakers • Within a restricted listening area • Invention: cross-talk cancellation! Each ear receives only one loudspeaker signal, like in binaural listening Implemented with digital filters January 18, 2019 Vesa Välimäki 12 6 1/18/2019 Moog Synthesizers • Analog electronics • Subtractive synthesis Periodic waveforms and filters • Popular in pop and rock music and in commercials Wendy Carlos: Switched-on- Bach (1968) January 18, 2019 Vesa Välimäki 13 1970s: Practical Applications • Bishnu Atal: Linear predictive coding, 1970 • Blesser & Lee: real-time digital delay unit, 1971 • First digital reverb: EMT Model 250, 1976 • BBC: Digital sound recording started in 1971 • E. Kurenniemi: synthesizer DIMI-600, 1972 • Chowning: , 1973 • Stockham: Restoration of old Caruso recordings, 1975 • Digital audio recording for consumers U-matic video cassette + a Sony PCM-1600 adapter, 1978 • First samplers: Synclavier, 1975; Fairlight CMI, 1978 January 18, 2019 Source of figure: Vesa Välimäki http://mixonline.com/TECnology-Hall-of- 14 Fame/1976-EMT-reverb/ 7 1/18/2019 Fairlight Computer Music Instrument • Early digital synthesizer Fairlight CMI IIx (1982) and sampler (1980-1984) Included a sequencer • Expensive (30000 USD) • Used in film industry and pop music in 1980s E.g. Kate Bush, Thomas Dolby, Peter Gabriel, Jan Hammer, Stevie Wonder (source: www.obsolete.com/120_years) January 18, 2019 Vesa Välimäki 15 Fairlight CMI Preset Sounds • Typical samples –Drums – A ”trained” dog – Human voices – Orchestra – Sounds from nature (source: http://120years.net) January 18, 2019 Vesa Välimäki 16 8 1/18/2019 Synclavier • Manufactured by New England Digital (USA 1976-1992) • Digital synthesizer and sampler Additive and FM synthesis Spectrum analyzer • Extremely expensive • Used in the film and pop music industry E.g., Michael Jackson, Sting, Frank Zappa (source:http://120years.net) January 18, 2019 Vesa Välimäki 17 1980s: Audio DSP Became Mainstream • Texas Instruments, Intel, NEC, Motorola: first digital signal processors, 1980- • Sony: Walkman cassette player, 1980 • Philips & Sony: , 1982 • Musical Instrument Digital Interface, MIDI, 1983 • Popular digital music synth: , 1983 • Sony: Digital Audio Tape (DAT), 1984 • First digital mixing consoles, 1986 • Ingrid Daubechies: wavelets, 1988 January 18, 2019 Vesa Välimäki 18 9 1/18/2019 CD • Developed by Philips and Sony since late 1970s • Brought audio DSP into homes since mid-1980s • Contains much digital signal processing Decoding, error correction, oversampling, digital filters, DA converters Sony prototype (1981) Sony CDP-101 (1982) January 18, 2019 Vesa Välimäki 19 Yamaha DX-7 Music Synthesizer • The first affordable digital music synthesizer (2000 €) • FM synthesis only Good for metallic, clear sounds, such as electric piano, tubular bells, celesta etc. • Huge commercial success in mid-1980s (source: www.obsolete.com/120_years) January 18, 2019 Vesa Välimäki 20 10 1/18/2019 1990s: Multi-Channel Sound and MPEG • International standards by Moving Picture Experts Group (MPEG) MPEG-1, MPEG-2, and MPEG-4 standards for video and audio coding MPEG-1 layer 3 = MP3, 1990; popular since late 1990s • New music players: Philips DCC, 1992-1996; Sony MiniDisk, 1992- • Digital multichannel sound for movies and home theater (5.1), 1992 • 3-D audio reproduction using HRTFs, ca. 1992 • First applications of active noise control • Physical modeling synthesis: Yamaha VL-1, 1994 • 1995: The Internet changed everything! (Not immediately) • Steinberg, VST plug-ins (Virtual Studio Technology), 1996 • First MP3 players, 1998 • Auto-tune for the singing voice, 1998 • European digital radio (Digital Audio Broadcasting, DAB) January 18, 2019 Vesa Välimäki 21 Korg Prophecy Synthesizer • A physical and analog modeling synthesizer (1995) January 18, 2019 Vesa Välimäki 22 11 1/18/2019 2000-2009: Mobile Audio • More disk formats: Super Audio CD, DVD Audio, Blu-ray • New audio coding techniques WMA, mp3PRO, AAC+, AMR-WB+, and about 100 others • Apple iPod music player, 2001 • MPEG-7 standard, “Multimedia Content Description Interface”, 2001 How to search and manage digitized audiovisual content Requires high-level audio processing (sound recognition, classification,…) • MPEG-21 standard, “Networked Multimedia Framework” Managing the whole multimedia delivery and consumption chain • Nokia: Polyphonic ring tones, 2002 • Sony-Ericsson: Music phones, 2005 • Music games: SingStar, 2004; GuitarHero 2005; RockBand 2007 • More music files sold than CDs, 2008- January 18, 2019 Vesa Välimäki 23 2010-2019 • Group work • Please brainstorm with the person next to you. Try to list products/inventions related to audio signal processing that have appears during this decade. • How has the world changed? What’s possible now but wasn’t earlier? January 18, 2019 Vesa Välimäki 24 12 1/18/2019 2010-2019 Vesa Välimäki January 18, 2019 25 Current Audio DSP Applications • Phones, music & media players (DVD, MP3) • Loudspeakers & headphones • Computers & gaming • Music synthesizers & effects boxes • Digital radio (DAB) & TV broadcasting • Cinema, home entertainment & car audio • Hearing aids • Professional audio • Active noise control in headsets and cars January 18, 2019 Vesa Välimäki 26 13 1/18/2019 Turning Points in Audio History • Birth of electroacoustics (ca. 1925) Microphone, loudspeaker, amplifier, radio, sound recording, talking movies, PA systems • Solid state electronics (ca. 1955) Transistors and diodes replace tubes, audio electronics becomes affordable