WIKIBOOKS
DISPONIBILI
?????????

ART
- Great Painters
BUSINESS&LAW
- Accounting
- Fundamentals of Law
- Marketing
- Shorthand
CARS
- Concept Cars
GAMES&SPORT
- Videogames
- The World of Sports

COMPUTER TECHNOLOGY
- Blogs
- Free Software
- Google
- My Computer

- PHP Language and Applications
- Wikipedia
- Windows Vista

EDUCATION
- Education
LITERATURE
- Masterpieces of English Literature
LINGUISTICS
- American English

- English Dictionaries
- The English Language

MEDICINE
- Medical Emergencies
- The Theory of Memory
MUSIC&DANCE
- The Beatles
- Dances
- Microphones
- Musical Notation
- Music Instruments
SCIENCE
- Batteries
- Nanotechnology
LIFESTYLE
- Cosmetics
- Diets
- Vegetarianism and Veganism
TRADITIONS
- Christmas Traditions
NATURE
- Animals

- Fruits And Vegetables



ARTICLES IN THE BOOK

  1. Acoustics
  2. AKG Acoustics
  3. Audio feedback
  4. Audio level compression
  5. Audio quality measurement
  6. Audio-Technica
  7. Balanced audio connector
  8. Beyerdynamic
  9. Blumlein Pair
  10. Capacitor
  11. Carbon microphone
  12. Clipping
  13. Contact microphone
  14. Crosstalk measurement
  15. DB
  16. Decibel
  17. Directional microphone
  18. Dynamic range
  19. Earthworks
  20. Electret microphone
  21. Electrical impedance
  22. Electro-Voice
  23. Equal-loudness contour
  24. Frequency response
  25. Georg Neumann
  26. Harmonic distortion
  27. Headroom
  28. ITU-R 468 noise weighting
  29. Jecklin Disk
  30. Laser microphone
  31. Lavalier microphone
  32. Loudspeaker
  33. M-Audio
  34. Microphone
  35. Microphone array
  36. Microphone practice
  37. Microphone stand
  38. Microphonics
  39. Nevaton
  40. Noise
  41. Noise health effects
  42. Nominal impedance
  43. NOS stereo technique
  44. ORTF stereo technique
  45. Parabolic microphone
  46. Peak signal-to-noise ratio
  47. Phantom power
  48. Pop filter
  49. Positive feedback
  50. Rode
  51. Ribbon microphone
  52. Schoeps
  53. Sennheiser
  54. Shock mount
  55. Shure
  56. Shure SM58
  57. Signal-to-noise ratio
  58. Soundfield microphone
  59. Sound level meter
  60. Sound pressure
  61. Sound pressure level
  62. Total harmonic distortion
  63. U 47
  64. Wireless microphone
  65. XLR connector

 

 



MICROPHONES
This article is from:
http://en.wikipedia.org/wiki/Clipping_%28audio%29

All text is available under the terms of the GNU Free Documentation License: http://en.wikipedia.org/wiki/Wikipedia:Text_of_the_GNU_Free_Documentation_License 

Clipping (audio)

From Wikipedia, the free encyclopedia

 
The picture shows an oscilloscope screen of an amplifier "clipping."  The amplifier should be outputting a clean sine wave with rounded tops and bottoms, but instead they are cut off flat, or "clipped", as if they had been cut with a pair of scissors or shears.
The picture shows an oscilloscope screen of an amplifier "clipping." The amplifier should be outputting a clean sine wave with rounded tops and bottoms, but instead they are cut off flat, or "clipped", as if they had been cut with a pair of scissors or shears.
This PCM waveform is clipped between the red lines
This PCM waveform is clipped between the red lines

Clipping is a form of distortion that occurs when an amplifier is overdriven, which happens when it attempts to increase voltage or current beyond its limits.

Overview of clipping

When an amplifier is pushed to create a signal with more power than it can support, it will amplify the signal only up to its maximum capacity, at which point the signal will be amplified no further. As the signal simply "cuts" or "clips" at the maximum capacity of the amplifier, the signal is said to be "clipping." The extra signal which is beyond the capability of the amplifier is simply cut off, resulting in a distorted waveform.

Many electric guitar players intentionally overdrive their guitar amplifiers to cause clipping in order to get a desired sound. See Guitar distortion.

All amplifiers have a maximum amount of power, so theoretically they all can clip. However, many amplifiers will not allow a user to turn gain up beyond that point, so that the amplifier never clips. This is sometimes to reduce accidental distortion, or more importantly, to keep from damaging the amplifier as some amplifiers cannot withstand the heat generated by some forms of clipping.

Effects of clipping

In power amplifiers, the signal from an amplifier operating in clipping has two characteristics that could damage a connected loudspeaker:

  • Because the clipped waveform has more area underneath it than the smaller unclipped waveform, the amplifier produces more power when it is clipping. This extra power can damage any part of the loudspeaker, including the woofer or the tweeter, by causing overexcursion, or by overheating the voice coil.
  • In the frequency domain, clipping produces strong harmonics in the high frequency range. The extra high frequency weighting of the signal could make tweeter damage more likely than if the signal was not clipped. However most loudspeakers are designed to handle signals like cymbal crashes that have even more high frequency weighting than amplifier clipping produces, so damage attributable to this characteristic is rare.

Digital clipping

In digital signal processing, clipping occurs when the signal is restricted by the range of a chosen representation. For example in a system using 16-bit signed integers, 32767 is the largest positive value that can be represented, and if during processing the amplitude of the signal is doubled, sample values of 32000 should become 64000, but instead they are truncated to the maximum, 32767. Clipping is preferable to the alternative in digital systems wrapping which occurs if the digital hardware is allowed to "overflow", ignoring the most significant bits of the magnitude, and sometimes even the sign of the sample value, resulting in terrible modification of the signal.

Sources of clipping

In analogue audio equipment, there are three common causes of clipping.

  • An integrated circuit or discrete solid state amplifier cannot give an output voltage larger than the voltage it is powered by (commonly a 24- or 30-volt spread for operational amplifiers used in line level equipment).
  • A vacuum tube can only move a limited number of electrons in an amount of time, dependent on its size, temperature, and metals.
  • A transformer (most commonly used between stages in tube equipment) will clip when its ferromagnetic core becomes electromagnetically saturated.

Some audiophiles believe that the clipping behavior of vacuum tubes is superior to that of transistors, in that vacuum tubes clip more gradually than transistors, resulting in harmonic distortion that is generally less objectionable.

See also

  • Loudness war
  • Valve sound
  • Clipper
  • Overdrive (music)
Retrieved from "http://en.wikipedia.org/wiki/Clipping_%28audio%29"