Audio

Digital Audio

 * What is Audio?**
 * "Audio is the human interpretation of sound" (Rowe 1997)
 * By sound, we commonly mean the vibrations that travel through air and are audible to people


 * The 4 categories of Sound**
 * 1) Music: Music communicates artistic messages that are composed in a specific pattern. The organization of tones produces a coherent sequence of sounds.
 * 2) Language: Language is the use of sounds with established meaning and functions. Language is the foundation of a system of communication.
 * 3) Noise: Noise is neither music nor language. Noise refers to anything other than music or language. This could include our physical environment, sound effects, spontaneous emotions, etc.
 * 4) Silence: Silence is the absence of all sound


 * Audio Communication**
 * Audio communication can be further broken down into five diverse models:
 * 1) Broadcast Audio — Audio that is transmitted or sent out to the public (AM, FM and Internet Broadcast Radio).
 * 2) Audio with Visual — Audio and video images that are transmitted or sent out to the public. (Television and satellite signals)
 * 3) Recorded Audio — Audio that is saved on a medium (CD’s, cassette tapes and talking books).
 * 4) Two-Way — Audio that is transferred back and forth between two points (telephone, two-way radios and Internet communication via software such as MSN Messenger).
 * 5) Musical instruments — Any device used to produce musical sounds or tones (guitar, piano).


 * Podcast**
 * A podcast is a digital media file, or a related collection of such files, which is distributed over the Internet for playback on portable media players and personal computers.
 * The host or author of a podcast is often called a podcaster.
 * The term "podcast" is derived from the words "iPod" and "broadcast",the Apple iPod being the brand of portable media player for which the first podcasting scripts were developed
 * Though podcasters' web sites may also offer streaming of their content, a podcast is distinguished from other digital media formats by its ability to be downloaded

Soundscapes, a term devised by Canadian composer and music educator R. Murray Schafer, refers to the sounds that surround us, our acoustical environment
 * Soundscapes**

Soundscape example

[|Soundscape - Mr. Sturgeon]

The soundscape above might go with a picture such as this...


 * [[image:mrsturgeon:forest.jpg caption="Forest Stream"]] ||
 * Forest Stream ||

Assignment #1 - Creating your own soundscape.
[|mestchap3Assignment #1.doc]

**Radio Pioneers**

 * Michael Faraday**
 * Began a series of experiments in which he discovered electromagnetic induction in 1831
 * Faraday proposed that electromagnetic forces extended into the empty space around the conductor which in simple terms means that electromagnetic waves can travel through the air.


 * Mahlon Loomis **
 * credited with inventing the wireless telegraph in 1872
 * This patent utilizes atmospheric electricity to eliminate the overhead wire used by the existing telegraph systems


 * Heinrich Rudolf Hertz **
 * Was the first person to intentionally transmit and receive radio
 * Famously, he saw no practical use for his discovery
 * __Side note__: The **hertz** (symbol: **Hz**) is a unit of frequency. It is defined as the number of complete cycles per second. It is the basic unit of frequency in the International System of Units (SI), and is most commonly used for describing radio and audio frequencies.


 * Nikola Tesla**
 * After 1892, Tesla delivered a widely reported presentation before the Institution of Electrical Engineers of London in which he suggested that messages could be transmitted without wires.
 * He transmitted electromagnetic energy without wires, building the first radio transmitter in 1894.
 * Tesla also investigated harvesting energy that is present throughout space . He believed that it was just merely a question of time when men will succeed in attaching their machinery to the very wheelwork of nature, stating: "Ere many generations pass, our machinery will be driven by a power obtainable at any point of the universe."
 * The SI unit used to measure magnetic field is named after him, the tesla.
 * In 1943, the Supreme Court of the United States credited him as being the inventor of the radio.


 * Guglielmo Marconi**
 * Has been called the //father of radio//
 * He is said to have read about the experiments that Hertz and studied Tesla's work.
 * It was at this time that Marconi began to understand that radio waves could be used for wireless communications.
 * Marconi's early apparatus was a development of Hertz’s laboratory apparatus into a system designed for communications purposes.
 * His demonstrations of the use of radio for wireless communications, equipping ships with life saving wireless communications and establishing the first transatlantic radio service.
 * In 1902, Marconi transmitted from his station in Glace Bay, Nova Scotia, Canada across the Atlantic, and on 18 January 1903 a Marconi station built in Wellfleet, Massachusetts in 1901 sent a message of greetings from Theodore Roosevelt, the President of the United States, to King Edward VII of the United Kingdom, marking the first transatlantic radio transmission originating in the United States.
 * Marconi would later found the Marconi Company and would jointly receive the 1909 Nobel Prize in Physics for contribution to the existing radio sciences.

Early Commercial Radio

 * Before 1920, broadcasting was done by the navy or radio hobbyists and was limited to those people who owned receivers
 * Dr. Frank Conrad, an engineer for Westinghouse, experimented with broadcasting equipment
 * He would go on air three times a week, requesting that if anyone heard him, to send in a postcard.
 * When he was short for words, he would place the radio microphone beside his victrola (a type of record player or phonograph), crank the machine and play music. (This made him the first radio disc jockey).
 * Two years after this broadcast, there were more than 1.5 million radios in the United States and more than 500 broadcasting stations.
 * The initial receivers required headsets, while the later versions had loudspeakers, allowing families to sit down together for an evening of entertainment.
 * Early broadcasts included music, news, radio plays, sporting events and election results.
 * This format continued until television arrived, when the radio audience was captivated and entertained by television.
 * Only when this happened, did radio switch formats and place a heavy emphasis on music and news.

According to Statistics Canada:
 * Radio Stats**
 * Canadians spend, on average, 20.4 hours per week listening to the radio.
 * Based on a survey of 80 000 Canadians, Québec, Prince Edward Island and Alberta have the highest listenership.
 * The most popular music format was adult contemporary, with 25% of the total listenership.
 * Teenagers tune-in about half as often as adults and they favour FM stations.
 * Over two-thirds of listeners prefer FM radio.

An effective programming schedule depends upon a number of factors. Program Directors need to select:
 * Radio Programs**
 * the right DJ (disc jockey)
 * the right time slot
 * the best material for each time slot.
 * Radio Revenue
 * The principal source of revenue for commercial radio in Canada is advertising.
 * The survival of a radio station depends upon the sale of airtime to advertisers.

The price of airtime for advertisements depends upon a number of variables:
 * 1) the number of listeners
 * 2) the socio-economic profile of listeners (how much they make and what do they do)
 * 3) the price and the availability of advertising space in competing forms of media.
 * If no one is listening, then no one will advertise with you.
 * The most successful radio stations build their audiences and keep them coming back by playing their favourite type of programming.


 * Writing Audio Scripts**
 * Writing for narration for Audacity is really about writing words for the ear.
 * Someone once said that audio listeners aren't one audience of thousands; they're thousands of audiences of one.
 * You should always write with "you" in a personal style, as if your were speaking directly to the person listening.
 * Audio narration must sound natural.
 * Stick to one idea per sentence when possible.
 * Check everything you write by reading it aloud. A sentence might look just fine on paper, but it could read awkwardly in the studio.
 * Use contractions and an informal tone. Don't be afraid to use fragments or end your sentences with a preposition.
 * Keep your writing simple


 * Radio Playlists**
 * Radio stations will monitor their audiences via rating services
 * They receive feedback on:
 * 1) how well they are delivering their programming to the audience
 * 2) the demographics on who is listening to their shows
 * 3) what is popular with their audiences
 * 4) when the audience is listening.
 * Based on this data, the stations will then create what is known as a playlist.
 * Playlists itemize the songs that will be played throughout a one to two hour time period.
 * If the existing format is failing, then radio stations will change their format. For example, stations have switched from contemporary to country in order to appease their listening audience.

AM & FM Radio
Sound information -- including pitch and loudness -- is carried by radio waves in one of two ways, depending on the type of radio station -- AM or FM


 * AM**
 * Stands for Amplitude Modulation
 * AM radio technology is simpler than FM radio.
 * An AM receiver detects amplitude variations in the radio waves at a particular frequency.
 * It then amplifies changes in the signal voltage to drive a loudspeaker or earphones.
 * The speed at which the amplitude changes determines the pitch of the sound, and the amount that it changes determines its loudness.
 * Broadcast band is from 520 kHz up to 1611 kHz


 * FM Radio**
 * FM, or Frequency modulation, stations alter the frequency of the carrier signal.
 * In this case, the speed at which the frequency changes determines the pitch, and the amount that it changes determines the loudness.
 * Broadcast band is from 87.5 to 108.0 MHz


 * Radio Waves**
 * Advantages and Disadvantages
 * Generally, AM carrier waves have much longer wavelengths than FM carrier waves, and as a result, they can bend around obstacles like mountains and buildings better than FM waves and can travel greater distances before the signal fades.
 * However, because information is coded in the amplitude of an AM carrier wave, things such as the hum from nearby appliances and sparks going off in passing cars can influence the amplitude and are more likely to interfere with the wave.


 * Radio Call Signs**
 * A call sign (also known as a callsign or call letters, or abbreviated as a call) is a unique designation for a transmitting station.
 * Each country has a set of alphabetic or numeric International Telecommunication Union-designated prefixes with which their call signs must begin. For example:
 * Canada uses //CF-CK//, //CY//-//CZ//, //VA-VG//, //VE//, //VO//, //VX//-//VY//, and //XJ//-//XO//.
 * Example CJMO-FM (known on air as C103) is a Canadian radio station broadcasting in Moncton, New Brunswick at 103.1 MHz.
 * The United States uses //K//, //W//, //N//, and //AA//–//AL//.


 * Internet Radio**
 * Internet radio (aka //e-Radio//) is an audio __broadcasting__ service transmitted via the __Internet__.
 * Broadcasting on the Internet is usually referred to as __webcasting__ since it is not transmitted broadly through wireless means but is delivered over the __World Wide Web__.
 * The term "e-Radio" suggests a __streaming medium__ (downloads as it plays)that presents listeners with a continuous //stream// of audio
 * Different from podcasts as podcasts are downloaded and then played.

Many radio stations offer their live programming in the form of streaming audio from their website like :
 * [|http://www.c103.com/]
 * [|http://www.k945.ca/]
 * [|http://www.xl96.com/]

Other popular e-Radio sites:
 * []
 * []
 * []


 * How Does Radio Work?**
 * At the most basic level, the radio broadcasts we hear take place in four stages.
 * 1) First, a microphone converts sound waves into electrical signals.
 * 2) Second, the electrical signal from the microphone changes, (or modulates) a radio wave called a carrier radio wave, so that it will contain the sound information. This carrier wave is emitted by the broadcast tower.
 * 3) Third, a receiving antenna on a radio tuned to the proper frequency picks up the carrier wave, which then travels to the receiver or radio.
 * 4) Finally, the receiver detects the modulation in the carrier wave and converts it back into electrical signals. The electrical signals are sent to a loudspeaker, which changes them once again into sound waves.


 * Satellite Radio**
 * Also called subscription radio (SR)
 * A digital radio signal that is broadcast by a communications satellite, which covers a much wider geographical range than regular radio signals.
 * It allows listeners to roam across an entire continent, listening to the same audio programming anywhere they go.
 * Radio services are usually subscription-based (monthly payment required)
 * It requires a special type of receiver
 * Providers usually carry a variety of news, weather, sports, and music channels, with the music channels generally being commercial-free.
 * XM and Sirius are the two most common satellite radio providers in Canada, and all of North America
 * Recently, XM was actually acquired by Sirius

Assignment #2
[|mestchap3Assignment #2.doc]

Assignment #3
[|mestchap3Assignment #3.doc]

Chapter Review
[|Digital Audio Review.doc]