Sound

In physics, sound is a vibration that propagates as a typically audible mechanical wave of pressure and displacement, through a medium such as air or water. In physiology and psychology, sound is the reception of such waves and their perception by the brain.

Acoustics

Acoustics is the interdisciplinary science that deals with the study of mechanical waves in gases, 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 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.

Point-blank range

Point-blank range is any distance over which the trajectory of a given projectile fired from a given weapon remains sufficiently flat that one can strike a target by firing at it directly. Point-blank range will vary by a weapon's external ballistics characteristics and target chosen. A weapon with a flatter trajectory will permit a longer maximum point-blank range for a given target size, while a larger target will allow a longer point-blank range for a given weapon.

In forensics and popular usage, point-blank range has come to mean extremely close "can't miss" range with a firearm, within four feet of its muzzle at moment of discharge yet not close enough to be a contact shot.

History

The term point-blank range is of French origin, deriving from pointé à blanc, "pointed at the target", with the word blanc used to describe a small white aiming spot formerly at the center of shooting targets. Today, point-blank range denotes the distance a marksman can expect to fire a specific weapon and hit a desired target without adjusting its fixed sights. If a weapon is sighted correctly and ammunition reliable, the same spot should be hit every time at point-blank range.

Record producer

A record producer (or music producer) has a very broad role in overseeing and managing the recording (i.e. "production") of a band or performer's music. A producer has many roles that may include, but are not limited to, gathering ideas for the project, selecting songs and/or session musicians, proposing changes to the song arrangements, coaching the artist and musicians in the studio, controlling the recording sessions, and supervising the entire process through audio mixing (recorded music) and, in some cases, to the audio mastering stage. Producers also often take on a wider entrepreneurial role, with responsibility for the budget, schedules, contracts, and negotiations.

In the 2010s, the recording industry has two kinds of producers with different roles: executive producer and music producer. Executive producers oversee project finances while music producers oversee the creation of music.

A music producer can, in some cases, be compared to a film director, with noted practitioner Phil Ek describing his role as "the person who creatively guides or directs the process of making a record, like a director would a movie. The audio engineering [person] would be more the cameraman of the movie." Indeed, in Bollywood music, the designation actually is music director. The music producer's job is to create, shape, and mold a piece of music. The scope of responsibility may be one or two songs or an artist's entire album – in which case the producer will typically develop an overall vision for the album and how the various songs may interrelate.

Khan Academy

Khan Academy is a non-profit educational organization created in 2006 by educator Salman Khan with the aim of providing a free, world-class education for anyone, anywhere. The organization produces short lectures in the form of YouTube videos. In addition to micro lectures, the organization's website features practice exercises and tools for educators. All resources are available for free to anyone around the world. The main language of the website is English, but the content is also available in other languages.

History

The founder of the organization, Salman Khan, was born in New Orleans, Louisiana, United States to immigrant parents from Bangladesh and India. After earning three degrees from the Massachusetts Institute of Technology (a BS in mathematics, a BS in electrical engineering and computer science, and an MEng in electrical engineering and computer science), he pursued an MBA from Harvard Business School.

In late 2004, Khan began tutoring his cousin Nadia who needed help with math using Yahoo!'s Doodle notepad.When other relatives and friends sought similar help, he decided that it would be more practical to distribute the tutorials on YouTube. The videos' popularity and the testimonials of appreciative students prompted Khan to quit his job in finance as a hedge fund analyst at Connective Capital Management in 2009, and focus on the tutorials (then released under the moniker "Khan Academy") full-time.

Audio engineer

An audio engineer works on the recording, manipulation, mixing, reproduction, and reinforcement of sound. Audio engineers work on the "...technical aspect of recording—the placing of microphones, the turning of pre-amp knobs, the setting of levels. The physical recording of any project is done by an engineer ... the nuts and bolts." Many audio engineers creatively use technologies to produce sound for film, radio, television, music, electronic products and computer games. Audio engineers also set up and operate sound reinforcement systems for concert, corporate, theatre, sporting and other events.

Alternatively, the term audio engineer can refer to a scientist or professional engineer who holds a B.Sc. or M.Sc. who designs, develops and builds new audio technologies working within the field of acoustical engineering.

Audio engineering concerns the creative and practical aspects of sounds including speech and music, as well as the development of new audio technologies and advancing scientific understanding of audible sound.