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Topic: Microphone


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In the News (Mon 18 Feb 19)

  
  Microphone   (Site not responding. Last check: 2007-11-07)
Microphones are important in many kinds of communications systems and in instruments that measure sound and noise.
Another common type, the crystal microphone, utilizes piezoelectric crystals, in which a voltage develops between two faces of the crystal when pressure is applied to the crystal.
Among the important characteristics of microphones are their frequency response, directionality, sensitivity, and immunity to outside disturbances such as shock or vibration.
library.thinkquest.org /C006657/electronics/microphone.htm   (440 words)

  
  Microphone - Wikipedia, the free encyclopedia
Electret microphones have existed since the 1920s but were considered impractical, but they have now become the most common type of all, used in many applications from high-quality recording and lavalier use to built-in microphones in small sound recording devices and telephones.
In a dynamic microphone a small movable induction coil, positioned in the magnetic field of a permanent magnet, is attached to the diaphragm.
A pressure gradient microphone is a microphone in which both sides of the diaphragm are exposed to the incident sound and the microphone is therefore responsive to the pressure differential (gradient) between the two sides of the membrane.
en.wikipedia.org /wiki/Microphone   (5399 words)

  
 Microphone - Iridis Encyclopedia   (Site not responding. Last check: 2007-11-07)
Electret microphones have existed since the 1920s but were considered impractical, but have now become the most common type of all, used in many applications from high-quality public address to built-in microphones in small sound recording devices.
In ribbon microphones a thin, corrugated metal ribbon is suspended in a magnetic field: vibration of the ribbon in the magnetic field generates a changing voltage.
A microphone with a cardioid directional characteristic is effectively a superposition of an omnidirectional and a figure-8 microphone; for sound waves coming from the back, the negative signal from the figure-8 cancels the positive signal from the omnidirectional element, whereas for sound waves coming from the front, the two add to each other.
www.iridis.com /Microphone   (2161 words)

  
 Encyclopedia at AudioXchange: Microphone - Online Store & Product Reviews   (Site not responding. Last check: 2007-11-07)
Microphones are used in many applications such as telephones, tape recorders, hearing aids and in radio and television broadcasting.
Electret microphones have existed since the 1920s but were considered impractical, but have now become the most common type of all, used in many applications from high-quality PA to built-in microphones in small sound recording devices.
When two directional microphones are placed coincidentally, typically at a 90+ degree angle to each other (typically with each microphone pointing to a side of the sound-stage), a stereo effect is achieved simply through intensity differences of the sound entering each microphone.
www.audioxchange.com /encyclopedia/Microphone.shtml   (1509 words)

  
 Microphone Data - Help on using the site
In capacitor microphones Max SPL is usually limited by the electronics rather than the capsule so a pre-attenuator or pad may be fitted to increase the range.
The division of microphones into “dynamic” or “capacitor” is rather too broad for the purposes of Microphone Data so narrower classifications (shown as icons at the head of the page) have been made to distinguish each microphone’s operating principles.
Lavalier microphones were originally hung around the neck but have long since shrunk to something tiny that is pinned on the lapel, hidden in the hair or disguised amongst clothing.
www.microphone-data.com /help.asp   (2197 words)

  
 Adobe - Flash Player : Help - Microphone settings   (Site not responding. Last check: 2007-11-07)
Microphone settings allow you to select a microphone, adjust its sensitivity, and reduce the echo that may be coming from your speakers.
To test your microphone, speak in a normal tone of voice and watch the indicator on the left.
To increase or decrease your microphone's sensitivity, move the slider to the right or the left, respectively.
www.macromedia.com /support/documentation/en/flashplayer/help/help03.html   (391 words)

  
 Microphones
Microphones produce a very small amount of current, which makes sense when you consider just how light the moving parts must be to accurately follow sound waves.
Dynamic microphones are essentially noise free, but the electronic circuit built into condensor types is a potential source of trouble, and must be carefully designed and constructed of premium parts.
The practical range of distance between the instrument and the microphone is determined by the point where the sound overloads the microphone or console at the near end, and the point where ambient noise becomes objectionable at the far end.
arts.ucsc.edu /EMS/Music/tech_background/TE-20/teces_20.html   (4848 words)

  
 Microphone Array Research
Microphone arrays have a distinct advantage as they enable hands-free acquisition of speech with little constraint on the user, and they can also provide information on the location of speakers.
Research into microphone array processing is thus required to reduce these disadvantages, enabling the advantages of microphone arrays to be exploited in practical systems.
To direct the research, we are investigating the use of microphone arrays in smart meeting rooms, although the aim is to develop generic techniques that could apply in different applications.
www.idiap.ch /~mccowan/arrays/arrays.html   (484 words)

  
 Georg Neumann GmbH - Products/Current Microphones//
The KMS 104 and KMS 105 microphones have been developed to permit optimal transmission of the human voice, and are thus microphones of choice for demanding live applications.
Since vocalist microphones are typically addressed at close range, for the bass frequency response of the microphones, electronic compensation is used for the proximity effect in the respective capsules.
Even at large distances, the microphones thus operate with a high signal-to-noise ratio, facilitating the freedom of movement and creativity that are important to the artist.
www.neumann.com /?lang=en&id=current_microphones&cid=kms105_description   (593 words)

  
 [No title]
Their main drawback compared to larger, more expensive microphones is a relatively high self-noise (roughly 30 to 40 dBa) but the self-noise is normally swamped by the ambient noise level at a concert.
The sounds that the two microphones record are exactly what the listener hears, including the effects of the outer ear (the pinna), the acoustic shadow of the head, and inter-ear phase and frequency response differences that provide localization cues (the information that lets you determine where a sound is coming from).
But because the microphone spacing is a bit narrow (7 to 9 inches instead of the more typical 24 to 36 inches) the stereo image may sound a bit compressed.
www.harmony-central.com /Other/mic-faq.txt   (12011 words)

  
 Howstuffworks "How do microphones work, and why are there so many different types?"
In a dynamic microphone, the diaphragm moves either a magnet or a coil when sound waves hit the diaphragm, and the movement creates a small current.
Ribbon microphones - In a ribbon microphone, a thin ribbon is suspended in a magnetic field.
Condenser microphones - A condenser microphone is essentially a capacitor, with one plate of the capacitor moving in response to sound waves.
www.howstuffworks.com /question309.htm   (600 words)

  
 STEREO MICROPHONE TECHNIQUES
The greater the angle between microphones, and the narrower the polar pattern, the wider the stereo spread.
With coincident and near-coincident techniques, the microphones should be rigidly mounted with respect to one another, so that they can be moved as a unit without disturbing their arrangement.
To reproduce all the instruments' timbres equally well, the microphone should have a broad, flat response at all angles of incidence within at least 90 degrees, that is, the polar pattern should be uniform with frequency.
www.tape.com /Bartlett_Articles/stereo_microphone_techniques.html   (3172 words)

  
 System Test
The data was taken with the microphone at 52" (1.32 m) in front of the panel and the panel being lowered by 4.5", 9" and 14" to increase the angle from zero to 5, 10 and 15 degrees.
The wiring diagram for a stereo microphone with output attenuator, if needed, and using the modified capsules is shown on the microph2.gif page.
Attenuation of the microphone output degrades the signal to noise ratio and should only be used, when the preamplifier gain can not be reduced.
www.linkwitzlab.com /sys_test.htm   (3045 words)

  
 Microphones
The signal from a ribbon microphone is generated as a motional voltage; the movement of the ribbon in the magnetic field generates a voltage proportional to the velocity of the ribbon.
Electret condenser microphones are not to be compared with the studio standard condenser microphones which have such excellent frequency response characteristics.
The electret class of microphones are condenser microphones which use a permanently polarized electret material for their diaphragms, thus avoiding the necessity for the biasing DC voltage required for the conventional condenser.
hyperphysics.phy-astr.gsu.edu /hbase/audio/mic2.html   (487 words)

  
 Microphones for your Home Studio   (Site not responding. Last check: 2007-11-07)
It is extremely difficult to make a microphone that is both sensitive enough to pick up the subtle nuances of a fine acoustic instrument while also being able to capture the brute force of a rock kick drum or a Marshall stack without overloading.
When placing cardioid-patterned microphones on a stage or in the studio, remember the 4-to-1 rule—each microphone should be at least four times as far from the next one as it is from the sound source.
Since the maximum distance between the sound source (the vocalist and the saxophonist) and their respective microphones will be one foot, the 4-to-1 rule dictates that the two microphones (and the two musicians) should be placed no less than four feet from eachother.
home.earthlink.net /~rongonz/home_rec/microphone.html   (4184 words)

  
 microphone - Hutchinson encyclopedia article about microphone
One of the simplest microphones is the telephone receiver mouthpiece, invented by Scottish–US inventor Alexander Graham Bell in 1876; other types of microphone are used with broadcasting and sound-film apparatus.
The condenser microphone is most commonly used in recording and works by a capacitor.
The signals, transmitted and amplified, can also be used for radio, television, or recording purposes, or in theatres and public halls for the relaying of speech, song, and taped sound to amplifiers placed at various points of the building.
encyclopedia.farlex.com /microphone   (378 words)

  
 CNN - Lander to listen for the sounds of Mars - November 1, 1999
The microphone is funded solely by the Planetary Society, a worldwide nonprofit organization devoted to encouraging space exploration and the search for extraterrestrial life.
Microphones in space exploration are not new, according to the Planetary Society.
Russian scientists sent a microphone to Venus in the 1980s and heard electrical discharges, although the results were not reported in the published literature.
www.cnn.com /TECH/space/9911/01/mars.microphone/index.html   (510 words)

  
 Laser microphone - Wikipedia, the free encyclopedia
It has been suggested that this article or section be merged into Microphone.
This technology can be used to secretly eavesdrop on people, with minimal chance of exposure unless specialized light sensors are used to detect the light from the beam.
Supposedly this type of microphone does not work on older "wavy" glass and modern reproductions of it, since it is an irregular surface.
en.wikipedia.org /wiki/Laser_microphone   (227 words)

  
 quiet american
Some microphones are specialized to specific kinds of recording: they are designed to capture only very loud or very soft sounds; they are intended to work in close proximity or at a distance; they capture ambiance well, or filter out peripheral sounds.
I wear microphones in a headband that appears, to the casual observer, to be a pair of headphones.
Head-worn stereo microphones (binaurals and similar) are, by definition, positioned on either temple or near the ears.
www.quietamerican.org /links_diy-mics.html   (1267 words)

  
 Microphone Preamplifier Project
Continuing on with the wand assembly, coil the tiny microphone leads around a pen or pencil so they form the shape of a spring, as shown in Figure 5 (or see picture).
You now have a durable and functional microphone wand which may be easily mounted to a tripod for loudspeaker testing.
Once the preamplifier and microphone wand are assembled, a few quick tests using a minimum of test equipment can help determine if it is working properly.
orca.st.usm.edu /~jmneal/preamp1.htm   (3984 words)

  
 Powering microphones
Typical electret condenser microphone capsule is a 2 terminal device (there are also 3 pin capsules) which approximates to a current source when biassed with around 1-9 volt and routinely consumes less than half a milliamp.
The microphone capsules are not usually too picky of the actual votlage, so generally anything in the range of 3V to 9V will work (although the voltage can sometime affect the microphone output voltage level somewhat).
The advantage of T-power is that the shield of the microphone cable need not be connected at both ends, thus this allows the common practice of disconnecting one end of the shield to a microphone in order to prevent hum (earth loops).
www.epanorama.net /circuits/microphone_powering.html   (4005 words)

  
 Microphone Technique
Some microphones are so insensitive that when a speaker is about two or more feet away, hardly any speech signal at all is converted to an electrical current (the basis operation of all microphones).
The most important principle in using an FM microphone in a classroom is for the user to ensure that it is switched on when the recipient is supposed to hear the utterance and tumed off when the message is not intended for the FM user (either individually or as a member of the class).
It should be noted that when using an FM microphone, the distance from the talker to the receiver has a negligible effect upon the loudness of the speech received by a child (within the range of the FM transmitter).
www.hearingresearch.org /Dr.Ross/microphone_technique.htm   (2977 words)

  
 Microphones
Microphones are transducers which detect sound signals and produce an electrical image of the sound, i.e., they produce a voltage or a current which is proportional to the sound signal.
Besides the variety of basic mechanisms, microphones can be designed with different directional patterns and different impedances.
Principle: the air movement associated with the sound moves the metallic ribbon in the magnetic field, generating an imaging voltage between the ends of the ribbon which is proportional to the velocity of the ribbon - characterized as a "velocity" microphone.
hyperphysics.phy-astr.gsu.edu /hbase/audio/mic.html   (281 words)

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