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113-436: Sound engineering is increasingly viewed as a creative profession and art form, where musical instruments and technology are used to produce sound for film, radio, television, music and video games. Audio engineers also set up, sound check and do live sound mixing using a mixing console and a sound reinforcement system for music concerts, theatre, sports games and corporate events. Alternatively, audio engineer can refer to

226-429: A root mean square (RMS) value. For example, 1 Pa RMS sound pressure (94 dBSPL) in atmospheric air implies that the actual pressure in the sound wave oscillates between (1 atm − 2 {\displaystyle -{\sqrt {2}}} Pa) and (1 atm + 2 {\displaystyle +{\sqrt {2}}} Pa), that is between 101323.6 and 101326.4 Pa. As the human ear can detect sounds with

339-507: A scientist or professional engineer who holds an engineering degree and who designs, develops and builds audio or musical technology working under terms such as electronic/electrical engineering or (musical) signal processing . Research and development audio engineers invent new technologies, audio software, equipment and techniques, to enhance the process and art of audio engineering. They might design acoustical simulations of rooms, shape algorithms for audio signal processing , specify

452-400: A basic mobile phone, which is only capable of voice calling and text messaging. Feature phones and basic mobile phones tend to use a proprietary, custom-designed software and user interface . By contrast, smartphones generally use a mobile operating system that often shares common traits across devices. The critical advantage that modern cellular networks have over predecessor systems is

565-434: A customer unit could use. A cellular network mobile phone system gets its name from dividing the service area into many small cells, each with a base station with (for example) a useful range on the order of a kilometer (mile). These systems have dozens or hundreds of possible channels allocated to them. When a subscriber is using a given channel for a telephone connection, that frequency is unavailable for other customers in

678-418: A few sets of radio channels (frequencies). Once these few channels were in use by customers, no further customers could be served until another user vacated a channel. It would be impractical to give every customer a unique channel since there would not be enough bandwidth allocated to the mobile service. As well, technical limitations such as antenna efficiency and receiver design limit the range of frequencies

791-663: A given area as modified by the environment and understood by people, in context of the surrounding environment. There are, historically, six experimentally separable ways in which sound waves are analysed. They are: pitch , duration , loudness , timbre , sonic texture and spatial location . Some of these terms have a standardised definition (for instance in the ANSI Acoustical Terminology ANSI/ASA S1.1-2013 ). More recent approaches have also considered temporal envelope and temporal fine structure as perceptually relevant analyses. Pitch

904-692: A good sound within a room. For audio engineers, architectural acoustics can be about achieving good speech intelligibility in a stadium or enhancing the quality of music in a theatre. Architectural Acoustic design is usually done by acoustic consultants. Electroacoustics is concerned with the design of headphones, microphones, loudspeakers, sound reproduction systems and recording technologies. Examples of electroacoustic design include portable electronic devices (e.g. mobile phones , portable media players , and tablet computers ), sound systems in architectural acoustics, surround sound and wave field synthesis in movie theater and vehicle audio . Musical acoustics

1017-405: A medium such as air, water and solids as longitudinal waves and also as a transverse wave in solids . The sound waves are generated by a sound source, such as the vibrating diaphragm of a stereo speaker. The sound source creates vibrations in the surrounding medium. As the source continues to vibrate the medium, the vibrations propagate away from the source at the speed of sound , thus forming

1130-523: A mobile device, such as a smartphone. The term "app" is a shortening of the term "software application". A common data application on mobile phones is Short Message Service (SMS) text messaging. The first SMS message was sent from a computer to a mobile phone in 1992 in the UK while the first person-to-person SMS from phone to phone was sent in Finland in 1993. The first mobile news service, delivered via SMS,

1243-401: A number of distinguishing features. The International Telecommunication Union measures those with Internet connection, which it calls Active Mobile-Broadband subscriptions (which includes tablets, etc.). In the developed world, smartphones have now overtaken the usage of earlier mobile systems. However, in the developing world, they account for around 50% of mobile telephony . Feature phone

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1356-488: A particular pitch is determined by pre-conscious examination of vibrations, including their frequencies and the balance between them. Specific attention is given to recognising potential harmonics. Every sound is placed on a pitch continuum from low to high. For example: white noise (random noise spread evenly across all frequencies) sounds higher in pitch than pink noise (random noise spread evenly across octaves) as white noise has more high frequency content. Duration

1469-501: A problem due to the design of the phone, the quality of the cellular network and compression algorithms used in long-distance calls . Audio quality can be improved using a VoIP application over WiFi . Cellphones have small speakers so that the user can use a speakerphone feature and talk to a person on the phone without holding it to their ear. The small speakers can also be used to listen to digital audio files of music or speech or watch videos with an audio component, without holding

1582-464: A single hand, since most thumbs cannot reach the entire screen surface; they may need to be shifted around in the hand, held in one hand and manipulated by the other, or used in place with both hands. Due to design advances, some modern smartphones with large screen sizes and "edge-to-edge" designs have compact builds that improve their ergonomics, while the shift to taller aspect ratios have resulted in phones that have larger screen sizes whilst maintaining

1695-517: A single platform. There are a huge variety of apps, including video games , music products and business tools. Up until that point, smartphone application distribution depended on third-party sources providing applications for multiple platforms, such as GetJar , Handango , Handmark , and PocketGear . Following the success of the App Store, other smartphone manufacturers launched application stores, such as Google's Android Market (later renamed to

1808-429: A small microchip called a Subscriber Identity Module or SIM card , in order to function. The SIM card is approximately the size of a small postage stamp and is usually placed underneath the battery in the rear of the unit. The SIM securely stores the service-subscriber key (IMSI) and the K i used to identify and authenticate the user of the mobile phone. The SIM card allows users to change phones by simply removing

1921-471: A telephone service area, which is divided up into 'cells'. Each cell uses a different set of frequencies from neighboring cells, and will typically be covered by three towers placed at different locations. The cell towers are usually interconnected to each other and the phone network and the internet by wired connections. Due to bandwidth limitations each cell will have a maximum number of cell phones it can handle at once. The cells are therefore sized depending on

2034-501: A university. Some positions, such as faculty (academic staff) require a Doctor of Philosophy . In Germany a Toningenieur is an audio engineer who designs, builds and repairs audio systems. The listed subdisciplines are based on PACS ( Physics and Astronomy Classification Scheme ) coding used by the Acoustical Society of America with some revision. Audio engineers develop audio signal processing algorithms to allow

2147-469: A very thin carbon microphone". Early predecessors of cellular phones included analog radio communications from ships and trains. The race to create truly portable telephone devices began after World War II, with developments taking place in many countries. The advances in mobile telephony have been traced in successive "generations", starting with the early zeroth-generation ( 0G ) services, such as Bell System 's Mobile Telephone Service and its successor,

2260-466: A wide range of amplitudes, sound pressure is often measured as a level on a logarithmic decibel scale. The sound pressure level (SPL) or L p is defined as Since the human ear does not have a flat spectral response , sound pressures are often frequency weighted so that the measured level matches perceived levels more closely. The International Electrotechnical Commission (IEC) has defined several weighting schemes. A-weighting attempts to match

2373-404: A wide range of applications, including post-production for video and film , live sound reinforcement, advertising , multimedia , and broadcasting. In larger productions, an audio engineer is responsible for the technical aspects of a sound recording or other audio production, and works together with a record producer or director, although the engineer's role may also be integrated with that of

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2486-549: A woman" and she was told women in the city were "still barefoot, pregnant and [singing] in the vocal booth." When Jonell Polansky arrived in Nashville in 1994, with a degree in electrical engineering and recording experience in the Bay Area, she was told "You're a woman, and we already had one"—a reference to Wendy Waldman . KK Proffitt, a studio "owner and chief engineer", states that men in Nashville do not want to have women in

2599-745: Is a vibration that propagates as an acoustic wave through a transmission medium such as a gas, liquid or solid. In human physiology and psychology , sound is the reception of such waves and their perception by the brain . Only acoustic waves that have frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. In air at atmospheric pressure, these represent sound waves with wavelengths of 17 meters (56 ft) to 1.7 centimeters (0.67 in). Sound waves above 20  kHz are known as ultrasound and are not audible to humans. Sound waves below 20 Hz are known as infrasound . Different animal species have varying hearing ranges . Sound

2712-412: Is a term typically used as a retronym to describe mobile phones which are limited in capabilities in contrast to a modern smartphone . Feature phones typically provide voice calling and text messaging functionality, in addition to basic multimedia and Internet capabilities, and other services offered by the user's wireless service provider . A feature phone has additional functions over and above

2825-488: Is also known as the Newton–Laplace equation. In this equation, K is the elastic bulk modulus, c is the velocity of sound, and ρ {\displaystyle \rho } is the density. Thus, the speed of sound is proportional to the square root of the ratio of the bulk modulus of the medium to its density. Those physical properties and the speed of sound change with ambient conditions. For example,

2938-399: Is an undesirable component that obscures a wanted signal. However, in sound perception it can often be used to identify the source of a sound and is an important component of timbre perception (see below). Soundscape is the component of the acoustic environment that can be perceived by humans. The acoustic environment is the combination of all sounds (whether audible to humans or not) within

3051-513: Is being used or not) using a technique known as multilateration to calculate the differences in time for a signal to travel from the mobile phone to each of several cell towers near the owner of the phone. The movements of a mobile phone user can be tracked by their service provider and, if desired, by law enforcement agencies and their governments. Both the SIM card and the handset can be tracked. China has proposed using this technology to track

3164-478: Is characterized by) its unique sounds. Many species, such as frogs, birds, marine and terrestrial mammals , have also developed special organs to produce sound. In some species, these produce song and speech . Furthermore, humans have developed culture and technology (such as music, telephone and radio) that allows them to generate, record, transmit, and broadcast sound. Noise is a term often used to refer to an unwanted sound. In science and engineering, noise

3277-424: Is commonly used for diagnostics and treatment. Infrasound is sound waves with frequencies lower than 20 Hz. Although sounds of such low frequency are too low for humans to hear as a pitch, these sound are heard as discrete pulses (like the 'popping' sound of an idling motorcycle). Whales, elephants and other animals can detect infrasound and use it to communicate. It can be used to detect volcanic eruptions and

3390-421: Is concerned with researching and describing the science of music. In audio engineering, this includes the design of electronic instruments such as synthesizers ; the human voice (the physics and neurophysiology of singing ); physical modeling of musical instruments; room acoustics of concert venues; music information retrieval ; music therapy , and the perception and cognition of music . Psychoacoustics

3503-445: Is defined as "(a) Oscillation in pressure, stress, particle displacement, particle velocity, etc., propagated in a medium with internal forces (e.g., elastic or viscous), or the superposition of such propagated oscillation. (b) Auditory sensation evoked by the oscillation described in (a)." Sound can be viewed as a wave motion in air or other elastic media. In this case, sound is a stimulus. Sound can also be viewed as an excitation of

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3616-418: Is heard; specif.: a. Psychophysics. Sensation due to stimulation of the auditory nerves and auditory centers of the brain, usually by vibrations transmitted in a material medium, commonly air, affecting the organ of hearing. b. Physics. Vibrational energy which occasions such a sensation. Sound is propagated by progressive longitudinal vibratory disturbances (sound waves)." This means that the correct response to

3729-492: Is offered by colleges and universities. Some audio engineers are autodidacts with no formal training, but who have attained professional skills in audio through extensive on-the-job experience. Audio engineers must have extensive knowledge of audio engineering principles and techniques. For instance, they must understand how audio signals travel, which equipment to use and when, how to mic different instruments and amplifiers, which microphones to use and how to position them to get

3842-465: Is perceived as how "long" or "short" a sound is and relates to onset and offset signals created by nerve responses to sounds. The duration of a sound usually lasts from the time the sound is first noticed until the sound is identified as having changed or ceased. Sometimes this is not directly related to the physical duration of a sound. For example; in a noisy environment, gapped sounds (sounds that stop and start) can sound as if they are continuous because

3955-457: Is perceived as how "low" or "high" a sound is and represents the cyclic, repetitive nature of the vibrations that make up sound. For simple sounds, pitch relates to the frequency of the slowest vibration in the sound (called the fundamental harmonic). In the case of complex sounds, pitch perception can vary. Sometimes individuals identify different pitches for the same sound, based on their personal experience of particular sound patterns. Selection of

4068-422: Is perceptible by humans has frequencies from about 20 Hz to 20,000 Hz. In air at standard temperature and pressure , the corresponding wavelengths of sound waves range from 17 m (56 ft) to 17 mm (0.67 in). Sometimes speed and direction are combined as a velocity vector ; wave number and direction are combined as a wave vector . Transverse waves , also known as shear waves, have

4181-558: Is performed by a sound engineer who specializes only in that part of the production. An audio engineer is proficient with different types of recording media, such as analog tape, digital multi-track recorders and workstations, plug-ins and computer knowledge. With the advent of the digital age, it is increasingly important for the audio engineer to understand software and hardware integration, from synchronization to analog to digital transfers. In their daily work, audio engineers use many tools, including: Sound In physics , sound

4294-943: Is the scientific study of how humans respond to what they hear. At the heart of audio engineering are listeners who are the final arbitrator as to whether an audio design is successful, such as whether a binaural recording sounds immersive. The production, computer processing and perception of speech is an important part of audio engineering. Ensuring speech is transmitted intelligibly, efficiently and with high quality; in rooms, through public address systems and through mobile telephone systems are important areas of study. A variety of terms are used to describe audio engineers who install or operate sound recording , sound reinforcement , or sound broadcasting equipment, including large and small format consoles . Terms such as audio technician , sound technician , audio engineer , audio technologist , recording engineer , sound mixer , mixing engineer and sound engineer can be ambiguous; depending on

4407-475: Is typically learned from years of experience listening to and mixing music in recording or live sound contexts. For education and training, there are audio engineering schools all over the world. According to Women's Audio Mission (WAM), a nonprofit organization based in San Francisco dedicated to the advancement of women in music production and the recording arts, less than 5% of the people working in

4520-428: Is used in some types of music. Mobile phone A mobile phone or cell phone is a portable telephone that can make and receive calls over a radio frequency link while the user is moving within a telephone service area, as opposed to a fixed-location phone ( landline phone ). The radio frequency link establishes a connection to the switching systems of a mobile phone operator , which provides access to

4633-468: The 5G NR (5G New Radio) standard. 5G can be implemented in low-band, mid-band or high-band millimeter-wave, with download speeds that can achieve gigabit-per-second (Gbit/s) range, aiming for a network latency of 1 ms. This near-real-time responsiveness and improved overall data performance are crucial for applications like online gaming , augmented and virtual reality , autonomous vehicles , IoT, and critical communication services. Smartphones have

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4746-648: The Improved Mobile Telephone Service . These 0G systems were not cellular , supported a few simultaneous calls, and were very expensive. The first handheld cellular mobile phone was demonstrated by John F. Mitchell and Martin Cooper of Motorola in 1973, using a handset weighing 2 kilograms (4.4 lb). The first commercial automated cellular network ( 1G ) analog was launched in Japan by Nippon Telegraph and Telephone in 1979. This

4859-888: The Philippines . A pilot project in Bali was launched in 2011 by the International Finance Corporation and an Indonesian bank, Bank Mandiri . Mobile payments were first trialled in Finland in 1998 when two Coca-Cola vending machines in Espoo were enabled to work with SMS payments. Eventually, the idea spread and in 1999, the Philippines launched the country's first commercial mobile payments systems with mobile operators Globe and Smart . Some mobile phones can make mobile payments via direct mobile billing schemes, or through contactless payments if

4972-649: The WCDMA standard. This was followed by 3.5G or 3G+ enhancements based on the high-speed packet access (HSPA) family, allowing UMTS networks to have higher data transfer speeds and capacity. 3G is able to provide mobile broadband access of several Mbit/s to smartphones and mobile modems in laptop computers. This ensures it can be applied to mobile Internet access, VoIP , video calls, and sending large e-mail messages, as well as watching videos, typically in standard-definition quality. By 2009, it had become clear that, at some point, 3G networks would be overwhelmed by

5085-401: The equilibrium pressure, causing local regions of compression and rarefaction , while transverse waves (in solids) are waves of alternating shear stress at right angle to the direction of propagation. Sound waves may be viewed using parabolic mirrors and objects that produce sound. The energy carried by an oscillating sound wave converts back and forth between the potential energy of

5198-483: The hearing range for humans or sometimes it relates to a particular animal. Other species have different ranges of hearing. For example, dogs can perceive vibrations higher than 20 kHz. As a signal perceived by one of the major senses , sound is used by many species for detecting danger , navigation , predation , and communication. Earth's atmosphere , water , and virtually any physical phenomenon , such as fire, rain, wind, surf , or earthquake, produces (and

5311-450: The internet of things (IoT), fixed wireless access , and multimedia streaming (including music, video, radio , and television ). Deployment of fifth-generation ( 5G ) cellular networks commenced worldwide in 2019. The term "5G" was originally used in research papers and projects to denote the next major phase in mobile telecommunication standards beyond the 4G / IMT-Advanced standards. The 3GPP defines 5G as any system that adheres to

5424-986: The public switched telephone network (PSTN). Modern mobile telephone services use a cellular network architecture, and therefore mobile telephones are called cellphones (or "cell phones") in North America. In addition to telephony , digital mobile phones support a variety of other services , such as text messaging , multimedia messaging , email , Internet access (via LTE , 5G NR or Wi-Fi ), short-range wireless communications ( infrared , Bluetooth ), satellite access ( navigation , messaging connectivity ), business applications, payments (via NFC ), multimedia playback and streaming ( radio , television ), digital photography , and video games . Mobile phones offering only basic capabilities are known as feature phones ( slang : "dumbphones" ); mobile phones that offer greatly advanced computing capabilities are referred to as smartphones . The first handheld mobile phone

5537-599: The screen . Depending on the device's type and design, the screen fills most or nearly all of the space on a device's front surface. Many smartphone displays have an aspect ratio of 16:9 , but taller aspect ratios became more common in 2017. Screen sizes are often measured in diagonal inches or millimeters ; feature phones generally have screen sizes below 90 millimetres (3.5 in). Phones with screens larger than 130 millimetres (5.2 in) are often called " phablets ." Smartphones with screens over 115 millimetres (4.5 in) in size are commonly difficult to use with only

5650-544: The Academy Award-nominated soundtrack to "Dirty Wars", Van-Ahn Vo (NPR's top 50 albums of 2013), Grammy-nominated St. Lawrence Quartet , and world music artists Tanya Tagaq and Wu Man . There certainly are efforts to chronicle women's role and history in audio. Leslie Gaston-Bird wrote Women in Audio, which includes 100 profiles of women in audio through history. Sound Girls is an organization focused on

5763-595: The GSM was used by over 5 billion people in over 220 countries. The GSM (2G) has evolved into 3G, 4G and 5G. The standardization body for GSM started at the CEPT Working Group GSM (Group Special Mobile) in 1982 under the umbrella of CEPT. In 1988, ETSI was established, and all CEPT standardization activities were transferred to ETSI. Working Group GSM became Technical Committee GSM. In 1991, it became Technical Committee SMG (Special Mobile Group) when ETSI tasked

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5876-493: The Google Play Store), RIM's BlackBerry App World , or Android-related app stores like Aptoide , Cafe Bazaar , F-Droid , GetJar , and Opera Mobile Store . In February 2014, 93% of mobile developers were targeting smartphones first for mobile app development. As of 2022, the top five manufacturers worldwide were Samsung (21%), Apple (16%), Xiaomi (13%), Oppo (10%), and Vivo (9%). From 1983 to 1998, Motorola

5989-655: The Liverpool Institute of Performing Arts, "only 6% of the students enrolled on its sound technology course are female." Women's Audio Mission was started in 2003 to address the lack of women in professional audio by training over 6,000 women and girls in the recording arts and is the only professional recording studio built and run by women. Notable recording projects include the Grammy Award-winning Kronos Quartet , Angelique Kidjo (2014 Grammy winner), author Salman Rushdie ,

6102-714: The SIM card from one mobile phone and inserting it into another mobile phone or broadband telephony device, provided that this is not prevented by a SIM lock . The first SIM card was made in 1991 by Munich smart card maker Giesecke & Devrient for the Finnish wireless network operator Radiolinja . A hybrid mobile phone can hold up to four SIM cards, with a phone having a different device identifier for each SIM Card. SIM and R-UIM cards may be mixed together to allow both GSM and CDMA networks to be accessed. From 2010 onwards, such phones became popular in emerging markets, and this

6215-421: The UK, the total number of mobile phones overtook the number of houses in 1999. Today, mobile phones are globally ubiquitous, and in almost half the world's countries, over 90% of the population owns at least one. A handheld mobile radio telephone service was envisioned in the early stages of radio engineering. In 1917, Finnish inventor Eric Tigerstedt filed a patent for a "pocket-size folding telephone with

6328-578: The ability to transfer cash payments by secure SMS text message. Kenya's M-PESA mobile banking service, for example, allows customers of the mobile phone operator Safaricom to hold cash balances which are recorded on their SIM cards. Cash can be deposited or withdrawn from M-PESA accounts at Safaricom retail outlets located throughout the country and can be transferred electronically from person to person and used to pay bills to companies. Branchless banking has also been successful in South Africa and

6441-550: The abnormally high traffic. Capacity was further increased when phone companies implemented digital networks. With digital, one frequency can host multiple simultaneous calls. Additionally, short-range Wi-Fi infrastructure is often used by smartphones as much as possible as it offloads traffic from cell networks on to local area networks. The common components found on all mobile phones are: Low-end mobile phones are often referred to as feature phones and offer basic telephony. Handsets with more advanced computing ability through

6554-404: The additional property, polarization , which is not a characteristic of longitudinal sound waves. The speed of sound depends on the medium the waves pass through, and is a fundamental property of the material. The first significant effort towards measurement of the speed of sound was made by Isaac Newton . He believed the speed of sound in a particular substance was equal to the square root of

6667-506: The audio and acoustic industry. Audio engineers in research and development usually possess a bachelor's degree , master's degree or higher qualification in acoustics, physics, computer science or another engineering discipline. They might work in acoustic consultancy, specializing in architectural acoustics . Alternatively they might work in audio companies (e.g. headphone manufacturer), or other industries that need audio expertise (e.g., automobile manufacturer), or carry out research in

6780-512: The basis of all sound waves. They can be used to describe, in absolute terms, every sound we hear. In order to understand the sound more fully, a complex wave such as the one shown in a blue background on the right of this text, is usually separated into its component parts, which are a combination of various sound wave frequencies (and noise). Sound waves are often simplified to a description in terms of sinusoidal plane waves , which are characterized by these generic properties: Sound that

6893-961: The benefits of different calling plans. For example, a particular plan might provide for cheaper local calls, long-distance calls, international calls, or roaming. The mobile phone has been used in a variety of diverse contexts in society. For example: In 1998, one of the first examples of distributing and selling media content through the mobile phone was the sale of ringtones by Radiolinja in Finland. Soon afterwards, other media content appeared, such as news, video games, jokes, horoscopes, TV content and advertising. Most early content for mobile phones tended to be copies of legacy media , such as banner advertisements or TV news highlight video clips. Recently, unique content for mobile phones has been emerging, from ringtones and ringback tones to mobisodes , video content that has been produced exclusively for mobile phones. In many countries, mobile phones are used to provide mobile banking services, which may include

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7006-465: The best quality recordings. In addition to technical knowledge, an audio engineer must have the ability to problem-solve quickly. The best audio engineers also have a high degree of creativity that allows them to stand out amongst their peers. In the music realm, an audio engineer must also understand the types of sounds and tones that are expected in musical ensembles across different genres— rock and pop music , for example. This knowledge of musical style

7119-469: The call, from detecting the presence of a handset in a service area, temporary assignment of a channel to a handset making a call, interface with the land-line side of the network to connect to other subscribers, and collection of billing information for the service. The automation systems can control the "hand off" of a customer handset moving between one cell and another so that a call in progress continues without interruption, changing channels if required. In

7232-399: The clock rate (generally given in multiples of hertz ) but also the memory hierarchy also greatly affects overall performance. Because of these problems, the performance of mobile phone CPUs is often more appropriately given by scores derived from various standardized tests to measure the real effective performance in commonly used applications. One of the main characteristics of phones is

7345-407: The committee with UMTS (3G). In addition to transmitting voice over digital signals, the 2G network introduced data services for mobile, starting with SMS text messages, then expanding to Multimedia Messaging Service (MMS), and mobile internet with a theoretical maximum transfer speed of 384 kbit/s (48 kB/s). In 2001, the third-generation ( 3G ) was launched in Japan by NTT DoCoMo on

7458-435: The concept of frequency reuse allowing many simultaneous telephone conversations in a given service area. This allows efficient use of the limited radio spectrum allocated to mobile services, and lets thousands of subscribers converse at the same time within a given geographic area. Former systems would cover a service area with one or two powerful base stations with a range of up to tens of kilometers' (miles), using only

7571-487: The context they may be synonymous, or they may refer to different roles in audio production. Such terms can refer to a person working in sound and music production; for instance, a sound engineer or recording engineer is commonly listed in the credits of commercial music recordings (as well as in other productions that include sound, such as movies). These titles can also refer to technicians who maintain professional audio equipment. Certain jurisdictions specifically prohibit

7684-477: The creative use of audio as a sound engineer, and (ii) training in science or engineering topics, which then allows students to apply these concepts while pursuing a career developing audio technologies. Audio training courses provide knowledge of technologies and their application to recording studios and sound reinforcement systems , but do not have sufficient mathematical and scientific content to allow someone to obtain employment in research and development in

7797-411: The duration of theta wave cycles. This means that at short durations, a very short sound can sound softer than a longer sound even though they are presented at the same intensity level. Past around 200 ms this is no longer the case and the duration of the sound no longer affects the apparent loudness of the sound. Timbre is perceived as the quality of different sounds (e.g. the thud of a fallen rock,

7910-415: The earliest mobile phone systems by contrast, all control was done manually; the customer would search for an unoccupied channel and speak to a mobile operator to request connection of a call to a landline number or another mobile. At the termination of the call the mobile operator would manually record the billing information. Mobile phones communicate with cell towers that are placed to give coverage across

8023-431: The electronic manipulation of audio signals. These can be processed at the heart of much audio production such as reverberation , Auto-Tune or perceptual coding (e.g. MP3 or Opus ). Alternatively, the algorithms might perform echo cancellation , or identify and categorize audio content through music information retrieval or acoustic fingerprint . Architectural acoustics is the science and engineering of achieving

8136-496: The end of 2009. In 2014, there were more than seven billion mobile phone subscribers worldwide, a number that is expected to keep growing. Mobile phones are used for a variety of purposes, such as keeping in touch with family members, for conducting business, and in order to have access to a telephone in the event of an emergency. Some people carry more than one mobile phone for different purposes, such as for business and personal use. Multiple SIM cards may be used to take advantage of

8249-401: The equation c = γ ⋅ p / ρ {\displaystyle c={\sqrt {\gamma \cdot p/\rho }}} . Since K = γ ⋅ p {\displaystyle K=\gamma \cdot p} , the final equation came up to be c = K / ρ {\displaystyle c={\sqrt {K/\rho }}} , which

8362-531: The ergonomics associated with smaller 16:9 displays. Liquid-crystal displays are the most common; others are IPS , LED , OLED , and AMOLED displays. Some displays are integrated with pressure-sensitive digitizers, such as those developed by Wacom and Samsung , and Apple's " 3D Touch " system. In sound, smartphones and feature phones vary little. Some audio-quality enhancing features, such as Voice over LTE and HD Voice , have appeared and are often available on newer smartphones. Sound quality can remain

8475-420: The expected usage density, and may be much smaller in cities. In that case much lower transmitter powers are used to avoid broadcasting beyond the cell. In order to handle the high traffic, multiple towers can be set up in the same area (using different frequencies). This can be done permanently or temporarily such as at special events or in disasters. Cell phone companies will bring a truck with equipment to host

8588-439: The extra compression (in case of longitudinal waves) or lateral displacement strain (in case of transverse waves) of the matter, and the kinetic energy of the displacement velocity of particles of the medium. Although there are many complexities relating to the transmission of sounds, at the point of reception (i.e. the ears), sound is readily dividable into two simple elements: pressure and time. These fundamental elements form

8701-406: The fastest in solid atomic hydrogen at about 36,000 m/s (129,600 km/h; 80,530 mph). Sound pressure is the difference, in a given medium, between average local pressure and the pressure in the sound wave. A square of this difference (i.e., a square of the deviation from the equilibrium pressure) is usually averaged over time and/or space, and a square root of this average provides

8814-525: The field of sound and media are women. "Only three women have ever been nominated for best producer at the Brits or the Grammys " and none won either award. According to Susan Rogers , audio engineer and professor at Berklee College of Music , women interested in becoming an audio engineer face "a boys' club, or a guild mentality". The UK "Music Producers' Guild says less than 4% of its members are women" and at

8927-486: The first quarter of 2016, the top smartphone developers worldwide were Samsung , Apple and Huawei ; smartphone sales represented 78 percent of total mobile phone sales. For feature phones as of 2016 , the top-selling brands were Samsung, Nokia and Alcatel . Mobile phones are considered an important human invention as they have been one of the most widely used and sold pieces of consumer technology. The growth in popularity has been rapid in some places, for example, in

9040-599: The growth of bandwidth-intensive applications, such as streaming media . Consequently, the industry began looking to data-optimized fourth-generation ( 4G ) technologies, with the promise of speed improvements up to tenfold over existing 3G technologies. The first publicly available LTE service was launched in Scandinavia by TeliaSonera in 2009. In the 2010s, 4G technology has found diverse applications across various sectors, showcasing its versatility in delivering high-speed wireless communication, such as mobile broadband,

9153-481: The hearing mechanism that results in the perception of sound. In this case, sound is a sensation . Acoustics is the interdisciplinary science that deals with the study of mechanical waves in gasses, liquids, and solids including vibration , sound, ultrasound, and infrasound. A scientist who works in the field of acoustics is an acoustician , while someone working in the field of acoustical engineering may be called an acoustical engineer . An audio engineer , on

9266-632: The influence of European companies had significantly decreased due to fierce competition from American and Asian companies, to where most technical innovation had shifted. Apple and Google, both of the United States, also came to dominate mobile phone software. The world's largest individual mobile operator by number of subscribers is China Mobile , which has over 902 million mobile phone subscribers as of June 2018 . Over 50 mobile operators have over ten million subscribers each, and over 150 mobile operators had at least one million subscribers by

9379-426: The information for timbre identification. Even though a small section of the wave form from each instrument looks very similar, differences in changes over time between the clarinet and the piano are evident in both loudness and harmonic content. Less noticeable are the different noises heard, such as air hisses for the clarinet and hammer strikes for the piano. Sonic texture relates to the number of sound sources and

9492-440: The interaction between them. The word texture , in this context, relates to the cognitive separation of auditory objects. In music, texture is often referred to as the difference between unison , polyphony and homophony , but it can also relate (for example) to a busy cafe; a sound which might be referred to as cacophony . Spatial location represents the cognitive placement of a sound in an environmental context; including

9605-414: The local cell and in the adjacent cells. However, cells further away can re-use that channel without interference as the subscriber's handset is too far away to be detected. The transmitter power of each base station is coordinated to efficiently service its own cell, but not to interfere with the cells further away. Automation embedded in the customer's handset and in the base stations control all phases of

9718-518: The next generation of women in audio, but also has been building up resources and directories of women in audio. Women in Sound is another organization that has been working to highlight women and nonbinary people in all areas of live and recorded sound through an online zine and podcast featuring interviews of current audio engineers and producers. One of the first women to produce, engineer, arrange and promote music on her own rock and roll music label

9831-461: The offset messages are missed owing to disruptions from noises in the same general bandwidth. This can be of great benefit in understanding distorted messages such as radio signals that suffer from interference, as (owing to this effect) the message is heard as if it was continuous. Loudness is perceived as how "loud" or "soft" a sound is and relates to the totalled number of auditory nerve stimulations over short cyclic time periods, most likely over

9944-482: The other hand, is concerned with the recording, manipulation, mixing, and reproduction of sound. Applications of acoustics are found in almost all aspects of modern society, subdisciplines include aeroacoustics , audio signal processing , architectural acoustics , bioacoustics , electro-acoustics, environmental noise , musical acoustics , noise control , psychoacoustics , speech , ultrasound , underwater acoustics , and vibration . Sound can propagate through

10057-399: The phone and the point of sale support near field communication (NFC). Enabling contactless payments through NFC-equipped mobile phones requires the co-operation of manufacturers, network operators, and retail merchants. Mobile phones are commonly used to collect location data. While the phone is turned on, the geographical location of a mobile phone can be determined easily (whether it

10170-567: The phone close to the ear. The average phone battery lasts two–three years at best. Many of the wireless devices use a Lithium-Ion (Li-Ion) battery, which charges 500–2500 times, depending on how users take care of the battery and the charging techniques used. It is only natural for these rechargeable batteries to chemically age, which is why the performance of the battery when used for a year or two will begin to deteriorate. Battery life can be extended by draining it regularly, not overcharging it, and keeping it away from heat. Mobile phones require

10283-580: The placement of a sound on both the horizontal and vertical plane, the distance from the sound source and the characteristics of the sonic environment. In a thick texture, it is possible to identify multiple sound sources using a combination of spatial location and timbre identification. Ultrasound is sound waves with frequencies higher than 20,000 Hz. Ultrasound is not different from audible sound in its physical properties, but cannot be heard by humans. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz. Medical ultrasound

10396-562: The pressure acting on it divided by its density: This was later proven wrong and the French mathematician Laplace corrected the formula by deducing that the phenomenon of sound travelling is not isothermal, as believed by Newton, but adiabatic . He added another factor to the equation— gamma —and multiplied γ {\displaystyle {\sqrt {\gamma }}} by p / ρ {\displaystyle {\sqrt {p/\rho }}} , thus coming up with

10509-500: The producer. In smaller productions and studios the sound engineer and producer are often the same person. In typical sound reinforcement applications, audio engineers often assume the role of producer, making artistic and technical decisions, and sometimes even scheduling and budget decisions. Audio engineers come from backgrounds or postsecondary training in fields such as audio, fine arts , broadcasting, music, or electrical engineering. Training in audio engineering and sound recording

10622-423: The production of harmonics and mixed tones not present in the original sound (see parametric array ). If relativistic effects are important, the speed of sound is calculated from the relativistic Euler equations . In fresh water the speed of sound is approximately 1,482 m/s (5,335 km/h; 3,315 mph). In steel, the speed of sound is about 5,960 m/s (21,460 km/h; 13,330 mph). Sound moves

10735-555: The question: " if a tree falls in a forest and no one is around to hear it, does it make a sound? " is "yes", and "no", dependent on whether being answered using the physical, or the psychophysical definition, respectively. The physical reception of sound in any hearing organism is limited to a range of frequencies. Humans normally hear sound frequencies between approximately 20  Hz and 20,000 Hz (20  kHz ), The upper limit decreases with age. Sometimes sound refers to only those vibrations with frequencies that are within

10848-491: The recording booth. At a meeting of the Audio Engineering Society , Proffitt was told to "shut up" by a male producer when she raised the issue of updating studio recording technologies. Proffitt said she "finds sexism rampant in the industry". Other notable women include: There are four distinct steps to the commercial production of a recording: recording, editing, mixing, and mastering. Typically, each

10961-550: The requirements for public address systems, carry out research on audible sound for video game console manufacturers, and other advanced fields of audio engineering. They might also be referred to as acoustic engineers. Audio engineers working in research and development may come from backgrounds such as acoustics , computer science , broadcast engineering , physics , acoustical engineering , electrical engineering and electronics . Audio engineering courses at university or college fall into two rough categories: (i) training in

11074-443: The response of the human ear to noise and A-weighted sound pressure levels are labeled dBA. C-weighting is used to measure peak levels. A distinct use of the term sound from its use in physics is that in physiology and psychology, where the term refers to the subject of perception by the brain. The field of psychoacoustics is dedicated to such studies. Webster's dictionary defined sound as: "1. The sensation of hearing, that which

11187-552: The second-generation ( 2G ) digital cellular technology was launched in Finland by Radiolinja on the GSM standard. This sparked competition in the sector as the new operators challenged the incumbent 1G network operators. The GSM standard is a European initiative expressed at the CEPT ("Conférence Européenne des Postes et Telecommunications", European Postal and Telecommunications conference). The Franco-German R&D cooperation demonstrated

11300-528: The sound is called the medium . Sound cannot travel through a vacuum . Studies has shown that sound waves are able to carry a tiny amount of mass and is surrounded by a weak gravitational field. Sound is transmitted through gases, plasma, and liquids as longitudinal waves , also called compression waves. It requires a medium to propagate. Through solids, however, it can be transmitted as both longitudinal waves and transverse waves . Longitudinal sound waves are waves of alternating pressure deviations from

11413-420: The sound wave. At a fixed distance from the source, the pressure , velocity , and displacement of the medium vary in time. At an instant in time, the pressure, velocity, and displacement vary in space. The particles of the medium do not travel with the sound wave. This is intuitively obvious for a solid, and the same is true for liquids and gases (that is, the vibrations of particles in the gas or liquid transport

11526-417: The speed of sound in gases depends on temperature. In 20 °C (68 °F) air at sea level, the speed of sound is approximately 343 m/s (1,230 km/h; 767 mph) using the formula v  [m/s] = 331 + 0.6  T  [°C] . The speed of sound is also slightly sensitive, being subject to a second-order anharmonic effect, to the sound amplitude, which means there are non-linear propagation effects, such as

11639-401: The technical feasibility, and in 1987, a Memorandum of Understanding was signed between 13 European countries that agreed to launch a commercial service by 1991. The first version of the GSM standard had 6,000 pages. The IEEE and RSE awarded Thomas Haug and Philippe Dupuis the 2018 James Clerk Maxwell medal for their contributions to the first digital mobile telephone standard. In 2018,

11752-699: The use of native software applications are known as smartphones . The first GSM phones and many feature phones had NOR flash memory, from which processor instructions could be executed directly in an execute in place architecture and allowed for short boot times. With smartphones, NAND flash memory was adopted as it has larger storage capacities and lower costs, but causes longer boot times because instructions cannot be executed from it directly, and must be copied to RAM memory first before execution. Mobile phones have central processing units (CPUs), similar to those in computers, but optimised to operate in low power environments. Mobile CPU performance depends not only on

11865-407: The use of the title engineer to any individual not a registered member of a professional engineering licensing body . In the recording studio environment, a sound engineer records, edits, manipulates, mixes, or masters sound by technical means to realize the creative vision of the artist and record producer . While usually associated with music production, an audio engineer deals with sound for

11978-566: The vibrations, while the average position of the particles over time does not change). During propagation, waves can be reflected , refracted , or attenuated by the medium. The behavior of sound propagation is generally affected by three things: When sound is moving through a medium that does not have constant physical properties, it may be refracted (either dispersed or focused). The mechanical vibrations that can be interpreted as sound can travel through all forms of matter : gases, liquids, solids, and plasmas . The matter that supports

12091-430: The whir of a drill, the tone of a musical instrument or the quality of a voice) and represents the pre-conscious allocation of a sonic identity to a sound (e.g. "it's an oboe!"). This identity is based on information gained from frequency transients, noisiness, unsteadiness, perceived pitch and the spread and intensity of overtones in the sound over an extended time frame. The way a sound changes over time provides most of

12204-599: Was Cordell Jackson (1923–2004). Trina Shoemaker is a mixer, record producer and sound engineer who became the first woman to win the Grammy Award for Best Engineered Album in 1998 for her work on The Globe Sessions . Gail Davies was the first female producer in country music , delivering a string of Top 10 hits in the 1970s and 1980s including " Someone Is Looking for Someone Like You ", " Blue Heartache " and " I'll Be There (If You Ever Want Me) ". When she moved to Nashville in 1976, men "didn't want to work for

12317-412: Was attributed to the desire to obtain the lowest calling costs. When the removal of a SIM card is detected by the operating system, it may deny further operation until a reboot. Feature phones have basic software platforms. Smartphones have advanced software platforms. Android OS has been the best-selling OS worldwide on smartphones since 2011. A mobile app is a computer program designed to run on

12430-587: Was demonstrated by Martin Cooper of Motorola in New York City on 3 April 1973, using a handset weighing c. 2 kilograms (4.4 lbs). In 1979, Nippon Telegraph and Telephone (NTT) launched the world's first cellular network in Japan. In 1983, the DynaTAC 8000x was the first commercially available handheld mobile phone. From 1983 to 2014, worldwide mobile phone subscriptions grew to over seven billion; enough to provide one for every person on Earth. In

12543-555: Was followed in 1981 by the simultaneous launch of the Nordic Mobile Telephone (NMT) system in Denmark, Finland, Norway, and Sweden. Several other countries then followed in the early to mid-1980s. These first-generation ( 1G ) systems could support far more simultaneous calls but still used analog cellular technology. In 1983, the DynaTAC 8000x was the first commercially available handheld mobile phone. In 1991,

12656-507: Was launched in Finland in 2000, and subsequently many organizations provided "on-demand" and "instant" news services by SMS. Multimedia Messaging Service (MMS) was introduced in March 2002. The introduction of Apple's App Store for the iPhone and iPod Touch in July 2008 popularized manufacturer-hosted online distribution for third-party applications (software and computer programs) focused on

12769-508: Was market leader in mobile phones. Nokia was the market leader in mobile phones from 1998 to 2012. In Q1 2012, Samsung surpassed Nokia, selling 93.5 million units as against Nokia's 82.7 million units. Samsung has retained its top position since then. Aside from Motorola, European brands such as Nokia, Siemens and Ericsson once held large sway over the global mobile phone market, and many new technologies were pioneered in Europe. By 2010,

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