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Hi-fi system

Belongs to:
Consumer electronics
Synonyms:
Audio system, Music centre, Sound system, Stereo, Stereo system
Description:

A stereo system is an electric music system that consists of different electric devices for the sound reproduction of different media, e.g. vinyl or digital media. The main characteristic of a stereo system is that it processes and reproduces two simultaneous, yet separated sound signals for spatial and binaural hearing.

A hi-fi system (hifi = High Fidelity) is an electric stereo system which covers in comparison to a conventional stereo system a broader sound spectrum.

The fundamental frequency of the emitted electric and magnetic fields is 50 Hz resp. 60 Hz due to the operation with voltage mains.

Frequency ranges:
  • 0 Hz
  • 30 Hz–20 kHz
Type of field:
electric and magnetic

Measurements (acc. to literature)

hi-fi system
Measurand Value Feature Remarks
magnetic flux density 0.02 µT (mean, measured) - average value of 30 devices at a distance of 1 m; measurement bandwidth: 40 - 800 Hz [1]
magnetic flux density 0.04–3 µT (maximum) - at a distance of 30 cm [2]
magnetic flux density 0.08 µT (mean, measured) - average value of 30 devices at a distance of 50 cm; measurement bandwidth: 40 - 800 Hz [1]
magnetic flux density 0.54 µT - at a distance of 10 cm [3]
magnetic flux density 1.56 µT (mean, measured) - average value of 30 devices at a distance of 5 cm; measurement bandwidth: 40 - 800 Hz [1]
magnetic flux density 170 µT (maximum) - at the surface of the device at 50 Hz [4]
stereo system
Measurand Value Feature Remarks
magnetic flux density 0.02 µT (mean, measured) - average value of 8 devices at a distance of 1 m; measurement bandwidth: 40 - 800 Hz [1]
magnetic flux density 0.06 µT (measured) - average of 23 devices at a distance of 50 cm; measurement bandwidth: 0 - 3 kHz [3]
magnetic flux density 0.07 µT (mean, measured) - average value of 8 devices at a distance of 50 cm; measurement bandwidth: 40 - 800 Hz [1]
magnetic flux density 0.48 µT (mean, measured) - average value of 8 devices at a distance of 5 cm; measurement bandwidth: 40 - 800 Hz [1]
magnetic flux density 0.54 µT (mean, measured) - average of 23 devices at a distance of 10 cm; measurement bandwidth: 0 - 3 kHz [3]

References

  1. Preece AW et al. (1997): Magnetic fields from domestic appliances in the UK.
  2. Neitzke HP et al. (2006): [EMF manual. Electromagnetic fields: sources, risks, protection].
  3. Ainsbury EA et al. (2005): An investigation into the vector ellipticity of extremely low frequency magnetic fields from appliances in UK homes.
  4. Leitgeb N et al. (2008): Magnetic emission ranking of electrical appliances. A comprehensive market survey.