Audio visualization
Audiovisualization refers to the dynamic presentation of graphics and animations on the basis of audio data such as music, speech or sounds. The aim is, on the one hand, to visualize certain information in the material in order to make it technically assessable and, on the other hand, visualization is also developing into an art form in which music is optically accompanied.
Technical application
Waveform
The simplest variant is the representation by oscilloscope . In the simplest case, the waveform of the audio signal is plotted over the course of the audio signal. This means that you let the electron beam of an oscilloscope run across the screen at a certain frequency and see the waveform of the audio signal.
Panoramic knife
Another variant is the panorama display (also called the correlation display) between the left and right audio channels. In this case, the audio signal for the left side controls the horizontal deflection of the electron beam, while the right audio signal controls the vertical deflection (left and right can also be swapped). This type of audio visualization is usually used in music studios or in TV or radio technology in order to be able to optically assess the stereo width of the signal being heard. The waveform display can be used to visually assess the noise component of quiet signals. In the panorama display you can also see how an audio signal is arranged in the room. The representation fluctuates between a diagonal line in the first square and such a line in the 4th quadrant, which means a complete decorrelation. As a rule, the display is circular for stereo signals pulsing. In the song Die Roboter by the Düsseldorf electro band Kraftwerk , the panorama display at the beginning of the song briefly shows a square.
Level meter
Another common display is the so-called peak meter . It shows the volume in the form of a bar. The classic that is still used in radio studios today is the RTW Peakmeter. The variants from NTP are also very well known. Peak meters are used to assess whether you are within a certain volume range. It is especially important to keep the volume level on the radio, as large fluctuations would disturb the listener. A peak meter is used by the moderators to check whether the volume is set correctly and whether audio signals are actually being transmitted to the transmitter. Otherwise a control on the mixer may not have been pulled up.
Combined level and panometer
The so-called correlation is important for the assessment. If a channel is twisted (left and right audio signals oscillate exactly in opposite directions), the signal can cancel each other out completely when mixed (switching to mono, radios that only play mono). The result would be that you can no longer hear anything, although a signal is present. The human ear cannot perceive phase shifts. Such phase rotators can only be judged visually. In older radio mixing consoles, the signals were mixed using operational amplifiers . The operational amplifiers used therein tended to shift the phase of audio signals. So-called correlation meters make such phase shifters optically visible and are integrated in modern peak meters. Phase shifters used to be observed with oscilloscopes, or with an additional peak meter that displayed the sum of both signals (mono). If the bars for the left and right sides moved, but the bar for the mono signal did not move or only barely, then there was a phase shift in the signal. In this case, the moderators have a button available that copies the right audio signal to the left channel or vice versa. In such a case, the audio signal is only “pseudo-stereo”, but can also be heard on mono radios. This effect is hardly present with modern, high-quality operational amplifiers (for example from BurrBrown). Since audio signals have been mixed digitally (using DSP ), the effect no longer occurs.
Spectrum analyzer
In a similar way, the individual spectral components of a sound can be shown graphically broken down according to frequencies. In signal processing systems, an FFT is often used for this purpose and the amplitudes of the signal components are plotted logarithmically.
Artistic application
Audiovisualization as an entertainment medium
Audiovisualization fascinates many people. In the 1970s, light organs became popular.
In 1976 the ATARI company sold a product called the Atari Video Music System C-240 Mint . This device was connected to the television or stereo system and displayed colorful images that moved or changed colors simultaneously with the music. The device first had to be connected to the socket and then to the stereo system, otherwise the stereo system could become defective.
The legendary Commodore 64 , which was used as a game console in the mid to late 1980s, had a large number of games, many with copy protection. Crackers cracked the copy protection and left a so-called cracktro as a business card on the data carriers. Today these "cracktros" are known under the name "Demo". A separate scene has formed around these demos (demo scene ). Very early on, moving bars and visual representations of the music running in the background were an essential part of these demos. Around 1985 this demo scene was continued on the Amiga from Commodore. The computers of the Amiga series had four audio channels, the corresponding formats were SID or Mod . In many demos, but also in computer games, the four bars (peak meter) were used as an optical effect for each of the audio channels. Around 1987 floppy disks with small collections of songs appeared ( MusicMags ), for example by the group Kaktus. These disks were loaded by the AMIGA within a few seconds and displayed a colorful universe of small, hectic graphics. In addition, a track could be selected from a list of hundreds of songs. Depending on the music, different greetings to other groups ran across the screen, which were distorted by the different elements of the music or changed in speed. These song collections were the first programs of their kind to display the elements of music on graphics and ultimately only served this purpose. The presentation of the music was almost celebrated by the graphics.
Since computers are fast enough, the frequency spectrum of an audio signal can be calculated in real time using the fast Fourier transform . This began for the PC platform with MS-DOS in the early 1990s, software that did that was e.g. B. the IntertiaPlayer or CubicPlayer , which achieved sufficient computing power on the still weak PC hardware through assembly language programming.
Soon after the development of the mp3 data format , an audio player called Winamp was released in May 1997 , with a plug-in based audio visualization concept (see also Winamp # visualization plug-ins ). Winamp was one of the first free mp3 players for PCs, achieved widespread use and shaped the audio player genre in terms of design, GUI and look and feel . A well-known audio-visualization plug-in was the Geiss plug-in from 1998, which for the first time generated a fractal-like visualization based on music.
Since Winamp, practically all audio and media players have been equipped with audio visualization, e.g. B. iTunes from Apple. The connection between music and video, however, is arbitrary and not always comprehensible.
Audiovisualization in Art
On Friday, November 30, 2001, the Viennese sound artists sha and GTT installed a steel construction of 14 giant sound monoliths on Dornerplatz in Vienna. It was the greatest work of sound in Europe. These monoliths were equipped with so-called NXT flat speakers. These loudspeakers make plates vibrate and thus transmit the sound. The 14 huge sound monoliths were supposed to function as an attempt to integrate urban problem areas. In this context, the term “audiovisualization” is used in a metaphorical sense. The problems of the city and the shadows that fall on them are 'audiovisualised'. This semantic of terms denotes the effect of sound and music on people's perception. The sound and the music visualize the problem in people's minds.
Audiovisualization in the field of design
A lot has happened in recent years, especially when it comes to designing company logos. Fonts were developed and expanded with logos. This combination is fixed once for a company and then lives on in the company's history as a corporate identity . Many design offices also offer "audio visualization" of the corporate identity. This is the design of identification melodies or tone sequences in addition to the logo. The five tones of the T-Com, the four tones that always appear in Intel advertising or the start melody of the Windows operating system from Microsoft are very well known. The consumer is always confronted with the logo and the audio logo at the same time. In this way, the consumer's subconscious connects the tone sequence (the acoustic logo) with the company name and logo. Nowadays one speaks of “identity mix” or “brand communication” instead of just corporate identity.
Examples
- Today, car radios use volume bars (peak meters) or a small frequency spectrum as audio visualization as a small optical gimmick.
- Some stereos display the frequency spectrum.
- Video recorders with adjustable recording volume show two peak meters.
- Laser shows in discos can be understood as audio visualization.
- Video jockeys (VJs) show pictures to the music in discos.
- Music videos can be seen as an extension of audio visualization.
List of visualization programs
(Years refer to the introduction)
- Music Animation Machine (1985, MAM)
- ZMusic (1987, Stephen Nachmanovitch)
- Virtual Light Machine (1990, Jeff Minter )
- Cthugha (1993, Kevin "Zaph" Burfitt, PC (DOS))
- Inertia Player 1995, (Stefan Danes, Ramon van Gorkom, et al. / Inertia Productions) Real-time spectrum visualization
- Visual Music Tone Painter (1992-2004, Stephen Nachmanovitch)
- Geiss-plugin (1998, Ryan Geiss), fractal visualization
- SoundSpectrum / G-Force (2000, Andy O'Meara, SoundSpectrum)
- MilkDrop (2001, Ryan Geiss) and OpenGL implementation, now projectM Open Source project
- R4 (2003, Gordon Williams)
- Vsxu (2003, Vovoid)
- Neon (2004, Jeff Minter and Ivan Zorzin)
- TronMe (2006, 3D Solar)
- iTunes (2006, Apple)
- Advanced Visualization Studio ( Justin Frankel )
- NoiseCradle (NoiseCradle)
- Windows Media Player ( Microsoft )
- fische (2001–2013, Marcel Ebmer), also as XBMC plug-in (fishBMC)
See also
literature
- Thomas Sandmann: Effects and Dynamics, Ppv Medien, 3rd edition, February 2003
Web links
- Atari Video Music System C-240
- Peak meter from RTW. The radio legend.
- Official Cthuga webpage for one of the first PC visualization programs
- Geisswerk , website of Milkdrop and Geiss-plug-in , one of the first PC audio-visualization plug -ins