A microphone, colloquially named mic or mike, is a device – a transducer – that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production and recorded audio engineering, sound recording, two-way radios, megaphones and television broadcasting, in computers for recording voice, speech recognition, VoIP, for non-acoustic purposes such as ultrasonic sensors or knock sensors. Several types of microphone are in use, which employ different methods to convert the air pressure variations of a sound wave to an electrical signal; the most common are the dynamic microphone. Microphones need to be connected to a preamplifier before the signal can be recorded or reproduced. In order to speak to larger groups of people, a need arose to increase the volume of the human voice; the earliest devices used to achieve this were acoustic megaphones. Some of the first examples, from fifth century BC Greece, were theater masks with horn-shaped mouth openings that acoustically amplified the voice of actors in amphitheatres.
In 1665, the English physicist Robert Hooke was the first to experiment with a medium other than air with the invention of the "lovers' telephone" made of stretched wire with a cup attached at each end. In 1861, German inventor Johann Philipp Reis built an early sound transmitter that used a metallic strip attached to a vibrating membrane that would produce intermittent current. Better results were achieved in 1876 with the "liquid transmitter" design in early telephones from Alexander Graham Bell and Elisha Gray – the diaphragm was attached to a conductive rod in an acid solution; these systems, gave a poor sound quality. The first microphone that enabled proper voice telephony was the carbon microphone; this was independently developed by David Edward Hughes in England and Emile Berliner and Thomas Edison in the US. Although Edison was awarded the first patent in mid-1877, Hughes had demonstrated his working device in front of many witnesses some years earlier, most historians credit him with its invention.
The carbon microphone is the direct prototype of today's microphones and was critical in the development of telephony and the recording industries. Thomas Edison refined the carbon microphone into his carbon-button transmitter of 1886; this microphone was employed at the first radio broadcast, a performance at the New York Metropolitan Opera House in 1910. In 1916, E. C. Wente of Western Electric developed the next breakthrough with the first condenser microphone. In 1923, the first practical moving coil microphone was built; the Marconi-Sykes magnetophone, developed by Captain H. J. Round, became the standard for BBC studios in London; this was improved in 1930 by Alan Blumlein and Herbert Holman who released the HB1A and was the best standard of the day. In 1923, the ribbon microphone was introduced, another electromagnetic type, believed to have been developed by Harry F. Olson, who reverse-engineered a ribbon speaker. Over the years these microphones were developed by several companies, most notably RCA that made large advancements in pattern control, to give the microphone directionality.
With television and film technology booming there was demand for high fidelity microphones and greater directionality. Electro-Voice responded with their Academy Award-winning shotgun microphone in 1963. During the second half of 20th century development advanced with the Shure Brothers bringing out the SM58 and SM57; the latest research developments include the use of fibre optics and interferometers. The sensitive transducer element of a microphone is called its capsule. Sound is first converted to mechanical motion by means of a diaphragm, the motion of, converted to an electrical signal. A complete microphone includes a housing, some means of bringing the signal from the element to other equipment, an electronic circuit to adapt the output of the capsule to the equipment being driven. A wireless microphone contains a radio transmitter. Microphones are categorized by their transducer principle, such as condenser, etc. and by their directional characteristics. Sometimes other characteristics such as diaphragm size, intended use or orientation of the principal sound input to the principal axis of the microphone are used to describe the microphone.
The condenser microphone, invented at Western Electric in 1916 by E. C. Wente, is called a capacitor microphone or electrostatic microphone—capacitors were called condensers. Here, the diaphragm acts as one plate of a capacitor, the vibrations produce changes in the distance between the plates. There are two types, depending on the method of extracting the audio signal from the transducer: DC-biased microphones, radio frequency or high frequency condenser microphones. With a DC-biased microphone, the plates are biased with a fixed charge; the voltage maintained across the capacitor plates changes with the vibrations in the air, according to the capacitance equation, where Q = charge in coulombs, C = capacitance in farads and V = potential difference in volts. The capacitance of the plates is inversely proportional to the distance between them for a parallel-plate capacitor; the assembly of fixed and movable plates is called an "element" or "capsule". A nearly constant charge is maintained on the capac
Richard Dennis was a Union Navy sailor in the American Civil War and a recipient of the U. S. military's highest decoration, the Medal of Honor, for his actions at the Battle of Mobile Bay. Dennis was born in 1826 in Massachusetts, he joined the Navy from Boston in March 1864, served during the Civil War as a boatswain's mate on the USS Brooklyn. At the Battle of Mobile Bay on August 5, 1864, he operated the ship's torpedo catcher and helped fire the bow chase gun despite heavy fire. For this action, he was awarded the Medal of Honor four months on December 31, 1864, he was discharged in February 1866. Dennis's official Medal of Honor citation reads: On board the U. S. S. Brooklyn during successful attacks against Fort Morgan, rebel gunboats and the ram Tennessee in Mobile Bay, on 5 August 1864. Despite severe damage to his ship and the loss of several men on board as enemy fire raked her decks from stem to stern, Dennis displayed outstanding skill and courage in operating the torpedo catcher and in assisting in working the bow chasers throughout the furious battle which resulted in the surrender of the prize rebel ram Tennessee and in the damaging and destruction of batteries at Fort Morgan
Andy Petree Racing was a NASCAR team that won 12 races. Formed in 1985 as Jackson Bros. Motorsports, ts ownership changed hands several times over the years, with three different owners from its beginning to its closure in 2004; the team was based out of North Carolina and was always a steady competitor for the win despite never winning a championship. The team was formed in 1985 by Richard Jackson. At the Daytona 500 that year, the team entered the No. 55 and No. 66 cars, sponsored by U. S. Smokeless Tobacco through its Copenhagen and Skoal brands and driven by another pair of brothers, Benny Parsons and his brother Phil. Benny finished Phil finished 29th, both suffering engine failure. Phil ran fourteen races with the team that year and posted three top 10s while splitting time with another ride, Benny ran fourteen races as well and had six top 10 finishes running a limited schedule; the two returned for 1986, when BP won the team's first pole position. Phil had five top-tens. After Benny left at the end of the year, his brother moved from the No. 66 to the No. 55.
In his first year with the No. 55, Phil Parsons finished a career-high fourth at Martinsville and finished 14th in points. The No. 66 ran only one race that year, with IndyCar driver Tom Sneva running at Daytona before dropping out with engine failure. In 1988, Parsons improved to a ninth-place finish in points, with the highlight of his year coming with his victory at the Winston 500 despite running out of fuel earlier in the race. In 1989 the team returned to a two-car operation, signing Harry Gant away from Mach 1 Racing with the Skoal sponsorship coming with him; the Jacksons traded numbers with Mach 1 owner Hal Needham and ran the No. 33 alongside the No. 55. Gant won early in the season at Darlington Speedway and finished seventh in points, while Parsons, despite additional sponsorship from Crown Petroleum, only had three top-tens and dropped to 21st in points. At the end of the year, Parsons left for Morgan-McClure Motorsports. In 1990, Richard Jackson splintered from the team to form his own operation, taking the equipment for the No. 55 with him.
The newly renamed Leo Jackson Motorsports still held onto the No. 33 and Gant who won at Pocono Raceway but finished 17th in points that year. Phil Parsons returned to the team following his release from Morgan-McClure, pulling substitute duty for Gant at Bristol Motor Speedway. 1991 was much better for Gant, as he finished 3rd in points and won four consecutive races late in the season, which began a "Life Begins at 51" campaign because Gant was the oldest winner in the history of the sport. He followed that up with his final two career wins in a fourth-place finish in points. In 1993 & 1994, he didn't win but had a pole each year as well as an eleventh-place finish in points in 1993. During his retirement year in 1994, LJM began grooming his replacement, Robert Pressley, ran three races for the team in the No. 54 sponsored by Manheim Auctions. His best finish was 31st, he moved to the No. 33 full-time in 1995, where he posted a tenth-place at Bristol, finished runner-up to Ricky Craven for Rookie of the Year.
1996 was a struggle for Pressley and the team, when Pressley was running decently before having to miss the first race at Dover Downs. Around this time, Jackson began looking to sell the team, his buyer was his crew chief at Andy Petree. After one race as an owner, he had Todd Bodine finish out the year for him. For 1997, Petree selected Ken Schrader to be his driver. Having won four Cup races, Schrader was solid all season long, as he won the pole for both Loudon races and finished tenth in the points standings. 1998 saw about the same result, with eight finishes of ninth or better, two more pole positions. APR expanded to a multi-car operation fielding the No. 55 Oakwood Homes-sponsored Chevy driven by Hut Stricklin in the Pepsi 400. The team became a multi-car full-time in 1999, with Kenny Wallace signing to drive the No. 55 car with a sponsorship from Square D. The year was "up and down" for Wallace, as he posted a career-best second-place finish at Loudon, but could only muster a 22nd-place points finish.
Meanwhile, in the No. 33 team, NASCAR's community was shocked when long-time sponsor Skoal announced it would no longer continue its association with the No. 33. After the team signed Oakwood Homes to be a full-time sponsor for the car, Schrader announced he would leave to pursue other opportunities. After a long search, APR decided to hire Joe Nemechek to pilot the car. While he didn't visit victory lane at all in 2000, he did have three top fives and the first top 25 points finish of his career. After nailing just one top 10 that year, Wallace announced. Wallace finished second at the Winston 500 at Talldega, it was Earnhardt's last victory before his death the following February in the Daytona 500. It wasn't long; when the 2000 season came to an end, APR fielded an unprecedented third team, the No. 35 for Geoffrey Bodine at Atlanta Motor Speedway. 2001 was a banner year for APR, as Hamilton won at Talladega Superspeedway in the same car that Wallace finished 2nd in with last fall, finished eighteenth in points, while Nemechek had ups and downs, breaking a shoulder at Dover and being replaced by Scott Pruett.
When he returned from his injuries, Nemechek was able to rebound with a victory at Rockingham Speedway and had a respectable 28th-place finish in points. Oakwood Homes had financi