Lights flash at frequency f = 0.5 Hz (Hz = hertz), 1.0 Hz and 2.0 Hz, where Failed to parse (Missing texvc executable; please see math/README to configure.): x

Hz means Failed to parse (Missing texvc executable; please see math/README to configure.): x
flashes per second. T is the period and T = Failed to parse (Missing texvc executable; please see math/README to configure.): y
s (s = second) means that Failed to parse (Missing texvc executable; please see math/README to configure.): y

is the number of seconds per flash. T and f are each other's reciprocal: f = 1/T and T = 1/f.

The hertz (symbol Hz) is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon.^[1] One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications. The word "hertz" is named for Heinrich Rudolf Hertz, who was the first to conclusively prove the existence of electromagnetic waves.

Definition[link]

The hertz is equivalent to cycles per second.^[2] In defining the second, the CIPM declared that "the standard to be employed is the transition between the hyperfine levels F = 4, M =  0 and F = 3, M = 0 of the ground state 2S_1/2 of the cesium 133 atom, unperturbed by external fields, and that the frequency of this transition is assigned the value 9 192 631 770 hertz"^[3] thereby effectively defining the hertz and the second simultaneously.

In English, hertz is used as a plural.^[4] As an SI unit, Hz can be prefixed; commonly used multiples are kHz (kilohertz, 10³ Hz), MHz (megahertz, 10⁶ Hz), GHz (gigahertz, 10⁹ Hz) and THz (terahertz, 10¹² Hz). One hertz simply means "one cycle per second" (typically that which is being counted is a complete cycle); 100 Hz means "one hundred cycles per second", and so on. The unit may be applied to any periodic event—for example, a clock might be said to tick at 1 Hz, or a human heart might be said to beat at 1.2 Hz. The "frequency" (activity) of aperiodic or stochastic events, such as radioactive decay, is expressed in becquerels.

Even though angular velocity, angular frequency and hertz all have the dimensions of 1/s, angular velocity and angular frequency are not expressed in hertz,^[5] but rather in an appropriate angular unit such as radians per second. Thus a disc rotating at 60 revolutions per minute (rpm) is said to be rotating at either 2π rad/s or 1 Hz, where the former measures the angular velocity and the latter reflects the number of complete revolutions per second. The conversion between a frequency f measured in hertz and an angular velocity ω measured in radians per second are:

Failed to parse (Missing texvc executable; please see math/README to configure.): \omega = 2\pi f \,

and Failed to parse (Missing texvc executable; please see math/README to configure.): f = \frac{\omega}{2\pi} \, 

. This SI unit is named after Heinrich Hertz. As with every International System of Units (SI) unit whose name is derived from the proper name of a person, the first letter of its symbol is upper case (Hz). When an SI unit is spelled out in English, it should always begin with a lower case letter (hertz), except where any word would be capitalized, such as at the beginning of a sentence or in capitalized material such as a title. Note that "degree Celsius" conforms to this rule because the "d" is lowercase. —Based on The International System of Units, section 5.2.

History[link]

The hertz is named after the German physicist Heinrich Hertz who made important scientific contributions to the study of electromagnetism. The name was established by the International Electrotechnical Commission (IEC) in 1930.^[6] It was adopted by the General Conference on Weights and Measures (CGPM) (Conférence générale des poids et mesures) in 1960, replacing the previous name for the unit, cycles per second (cps), along with its related multiples, primarily kilocycles per second (kc/s) and megacycles per second (Mc/s), and occasionally kilomegacycles per second (kMc/s). The term cycles per second was largely replaced by hertz by the 1970s.

The term "gigahertz", most commonly used in computer processor clock rates and radio frequency (RF) applications, can be pronounced either /ˈɡɪɡəhɜrts/, with a hard /ɡ/ sound, or /ˈdʒɪɡəhɜrts/, with a soft /dʒ/^[7] (see giga-#Pronunciation). The prefix "giga-" is derived directly from the Greek "γιγας" ("giant").

Applications[link]

Sine waves of different frequency.

Details of a heartbeat as an example of a non-sinusoidal periodic phenomenon that can be described in terms of hertz. Two complete cycles are illustrated.

Vibration[link]

Sound is a traveling wave which is an oscillation of pressure. Humans perceive frequency of sound waves as pitch. Each musical note corresponds to a particular frequency which can be measured in hertz. An infant's ear is able to perceive frequencies ranging from 20 Hz to 20,000 Hz; the average adult human can hear sounds between 20 Hz and 16,000 Hz.^[8] The range of ultrasound, high-intensity infrasound and other physical vibrations such as molecular vibrations extends into the megahertz range and well beyond.

Electromagnetic radiation[link]

Electromagnetic radiation is often described by its frequency—the number of oscillations of the perpendicular electric and magnetic fields per second—expressed in hertz.

Radio frequency radiation is usually measured in kilohertz (kHz), megahertz (MHz), or gigahertz (GHz). Light is electromagnetic radiation that is even higher in frequency, and has frequencies in the range of tens (infrared) to thousands (ultraviolet) of terahertz. Electromagnetic radiation with frequencies in the low terahertz range, (intermediate between those of the highest normally usable radio frequencies and long-wave infrared light), is often called terahertz radiation. Even higher frequencies exist, such as that of gamma rays, which can be measured in exahertz. (For historical reasons, the frequencies of light and higher frequency electromagnetic radiation are more commonly specified in terms of their wavelengths or photon energies: for a more detailed treatment of this and the above frequency ranges, see electromagnetic spectrum.)

Computing[link]

In computing, most central processing units (CPU) are labeled in terms of their clock rate expressed in megahertz or gigahertz (10⁶ or 10⁹ hertz, respectively). This number refers to the frequency of the CPU's master clock signal ("clock rate"). This signal is simply an electrical voltage which changes from low to high and back again at regular intervals. This signal is a square wave. Hertz has become the primary unit of measurement accepted by the general populace to determine the performance of a CPU, but many experts have criticized this approach, which they claim is an easily manipulable benchmark.^[9] For home-based personal computers, the CPU has ranged from approximately 1 megahertz in the late 1970s (Atari, Commodore, Apple computers) to up to 6 GHz in the present (IBM POWER processors) and up to 8 GHz overclocked (AMD FX processors).^[10]

Various computer buses, such as the front-side bus connecting the CPU and northbridge, also operate at different frequencies in the megahertz range

[edit] SI multiples

Frequencies not expressed in hertz[link]

Even higher frequencies are believed to occur naturally, in the frequencies of the quantum-mechanical wave functions of high-energy (or, equivalently, massive) particles, although these are not directly observable, and must be inferred from their interactions with other phenomena. For practical reasons, these are typically not expressed in hertz, but in terms of the equivalent quantum energy, which is proportional to the frequency by the factor of Planck's constant.

See also[link]

References[link]

External links[link]

• BIPM Cesium ion f_Cs definition
• National Research Council of Canada: Generation of the Hz
• National Research Council of Canada: Cesium fountain clock
• National Physical Laboratory: Trapped ion optical frequency standards
• National Research Council of Canada: Optical frequency standard based on a single trapped ion
• National Research Council of Canada: Optical frequency comb
• One Hertz in Radians per Second (Google). Note, as of 06 May 2009 there is an error of 2Failed to parse (Missing texvc executable; please see math/README to configure.): \pi

.

v t e SI units Base units Ampere · Candela · Kelvin · Kilogram · Metre · Mole · Second Derived units Becquerel · Coulomb · Degree Celsius · Farad · Gray · Henry · Hertz · Joule · Katal · Lumen · Lux · Newton · Ohm · Pascal · Radian · Siemens · Sievert · Steradian · Tesla · Volt · Watt · Weber Accepted for use with SI Dalton (Atomic mass unit) · Astronomical unit · Day · Decibel · Degree Celsius · Degree of arc · Electronvolt · Hectare · Hour · Litre · Minute · Minute of arc · Neper · Second of arc · Tonne Atomic units · Natural units See also SI prefixes · Systems of measurement · Conversion of units · New SI definitions · History of the metric system Book:International System of Units  · Category:SI base units

Richie Hawtin
Background information
Birth name	Richard Hawtin
Born	(1970-06-04) June 4, 1970 (age 42) Oxfordshire, England
Origin	Windsor, Ontario
Genres	Techno, minimal techno, Detroit techno, ambient
Labels	Plus 8, M-nus, NovaMute
Website	richiehawtin.com

Richard (Richie) Hawtin (born June 4, 1970, Banbury, Oxfordshire) is an English-Canadian electronic musician and DJ who was an influential part of Detroit techno's second wave of artists in the early 1990s and a leading exponent of Minimal techno since the mid 1990s. He is best known for his abstract, minimal works under the alias Plastikman, a pseudonym he still uses today.

Hawtin is known for DJing minimal techno sets making use of laptop computers and digital mixing equipment. In May 1990, Hawtin and fellow second-waver John Acquaviva founded the Plus 8 record label, which they named after their turntable's pitch adjust function.^[1] In 1998, Hawtin launched Minus records.^[2]

Biography[link]

Hawtin was born in Banbury, Oxfordshire, England,^[3] but moved when he was aged nine to LaSalle, Ontario, a suburb of Windsor, Ontario, and just across the river from Detroit, the birthplace of techno. His father worked as a robotics technician at General Motors, and was a fan of electronic music, introducing his son to Kraftwerk and Tangerine Dream at an early age. He has one brother, Matthew, who is a visual artist and ambient music DJ. Hawtin attended Sandwich Secondary High School in LaSalle. He began to DJ in clubs in Detroit at 17, and his early style was a mix of house music and techno.^[4]

With Canadian DJ John Acquaviva he formed the label Plus 8 in 1990 to release his own tracks under the name F.U.S.E.^[4] He spent part of 2002 and 2003 living in New York City, and has since moved to Berlin, Germany. He said, "I’d always wanted to move to Europe. I needed somewhere that was inspiring and where there were like-minded musicians and artists, somewhere you could still experiment with music and with life. Berlin is so liberal in so many different ways; there’s an amazing club scene, there’s a great development software tech scene, there are so many resources here."^[4]

Career[link]

	"Substance Abuse" noicon "Substance Abuse" was released in 1991 under the F.U.S.E pseudonym
Problems listening to this file? See media help.

	"Ping Pong" noicon The minimalist track "Ping Pong" was recorded under the Plastikman alias
Problems listening to this file? See media help.

Hawtin has recorded music under the aliases Plastikman, F.U.S.E., Concept 1, Forcept 1, Circuit Breaker, Robotman, Chrome, Spark, Xenon, R.H.X., Jack Master, Richard Michaels and UP!. He also recorded and performed, in combination with other artists, under group names such as The Hard Brothers, Hard Trax (with his brother Matthew Hawtin), 0733, Cybersonik (with Daniel Bell and John Acquaviva), Final Exposure (with Joey Beltram and Mundo Muzique), Just For Fun (with Holger Wick), Narod Niki (with Akufen, Cabanne, Dandy Jack, Daniel Bell, Luciano, Ricardo Villalobos, Robert Henke and Thomas Franzmann), Two Guys In The Basement (with John Acquaviva), Spawn (with Fred Giannelli and Daniel Bell) and States Of Mind (with Acquaviva).

He was the mastermind of huge raves in the Detroit area, he ran several club nights, a yearly party at City Club and a crazy one at The Necto (nightclub) Additionally, Hawtin and Pete Namlook collaborated to produce the From Within series of albums which blend minimal techno and ambient. He has also released an album Sounds of the Third Season with Sven Väth.^[5]

In 2006, Hawtin collaborated with choreographer Enzo Cosimi on a composition called "9.20" for the Winter Olympics opening ceremony. He said, "Enzo and I are very much interested in pushing boundaries, both as artists and for our audiences. Working together for the Opening Ceremonies of the Winter Games delivers the creative endeavor to not only entertain a huge audience, but to also introduce them to sights and sounds that they may have never experienced before."^[6]

Slices magazine launched a series of biographies in 2007 called "Pioneers of Electronic Music"; their first issue was a 60 minute biographical documentary on Hawtin. The film follows his career from his early days crossing the border to Detroit to his current life in Berlin, and contains interviews with many colleagues and family members.

2011 saw the release of Arkives 1993 - 2010, a massive box set containing everything Hawtin has released under his Plastikman moniker, as well as a new mixed set and previously unreleased material. The collection includes CDs, vinyl, digital downloads and a DVD.

Hawtin dismisses speculation as to the demise of dance music. In an interview he said, "In the last few years, the interest in electronic music has gone back up, the quality of the music has gone back up, there’s a buzz which reminds you of the early days,” he insists. “From where I’m sitting right now, dance music is more vibrant than ever. In some countries you’ll always have the press saying it’s going down and writing it off, but somewhere else the interest level is soaring and people are discovering this music for the first time, like in South America, where it’s completely kicking off – it’s unbelievable down there. There are some great festivals and parties in Europe, and over the last five years I’ve seen Ibiza go from complete cheesy shite music to the resurgence of a number of different types of progressive electronic music."^[4]

Selected discography[link]

Albums[link]

• F.U.S.E.: Dimension Intrusion, 1993
• Plastikman: Sheet One, 1993
• Plastikman: Musik, 1994
• Plastikman: Recycled Plastik, 1994
• Plastikman: Sickness (EP), 1997
• Concept 1: 96:CD, 1998
• Concept 1: 96:VR, 1998 (remixed by Thomas Brinkmann)
• Plastikman: Consumed, 1998
• Plastikman: Artifakts [bc], 1998
• Plastikman: Closer, 2003
• Plastikman: Kompilation, 2010
• Plastikman: Arkives, 2011

DJ mix compilations[link]

• Richie Hawtin: Mixmag Live!, 1995 (Live DJ mix album)
• Richie Hawtin: Decks, EFX & 909, 1999 (DJ mix album)
• Richie Hawtin: DE9: Closer to the Edit, 2001 (DJ mix album)
• Richie Hawtin and Sven Väth: Sound of the Third Season, 2002 (DJ mix album)
• Richie Hawtin and Ricardo Villalobos Live at the Robert Johnson, Offenbach, Germany, 2004 (11 hour DJ set)
• Richie Hawtin: DE9 | Transitions, 2005 (DJ mix album)
• Richie Hawtin: DE9 lite: Electronic Adventures, 2006 (DJ mix album, produced with MixMag)
• Richie Hawtin: Sounds from Can Elles, 2008 (unmixed various artist compilation, free with DJ Magazine issue 467)
• Richie Hawtin: Mixmag presents: Richie Hawtin - New Horizons, 2012 (DJ mix album)

Awards[link]

References[link]

External links[link]

Wikimedia Commons has media related to: Richie Hawtin

• Richie Hawtin's official site
• Plastikman's official site
• Richie Hawtin's Minus record label site
• Richie Hawtin's discography at Discogs