High fidelity

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Logo of the German Institute for Standardization DIN EN 61305
Area Consumer electronics
title Home Hi-Fi Equipment - Methods of Measuring and Specifying Performance Indicators
Brief description: Quality features for audio playback devices
Latest edition 1996-2005 (4 parts, 1 supplement)
ISO

High Fidelity [ ˌhaɪ̯fɪˈdɛləti: ] ( English 'high (sound) loyalty ', or Hi-Fi [ ˈhaɪ̯fɪ ], also  [ ˈhaɪ̯ˌfaɪ̯ ] ) is a quality standard in sound engineering . Please click to listen!Play

The guidelines were originally laid down in DIN 45500 in the 1960s . This DIN standard was replaced in 1996 by EN 61305, which only contains procedures for measuring and specifying the performance parameters, but no longer contains minimum requirements, as the requirements that were once standardized are no longer seen as a technical challenge.

technology

Frequency response

The human ear hears sounds from about 16 Hz to 20 kHz, the audio range , however, is individually different - an adult has an average bandwidth of the hearing of about 20 Hz to 16 kHz. Humans react most sensitively to tones between 2 kHz and 5 kHz, so that differences in pitch are best perceived here. For example, DIN 45500 stipulated a linear frequency response for magnetic sound technology in the range from 250 Hz to 6300 Hz for hi-fi home studio equipment, with a tolerance of up to 5 dB being permitted. According to DIN 45511, stricter rules applied to studio equipment: Only a tolerance of 3 dB was allowed in a frequency range from 80 Hz to 8000 Hz.

power

The RMS performance does not allow any conclusions to be drawn about the achievable volume. While large horn loudspeakers achieve a level of 105 dB with just 1 watt, many hi-fi loudspeakers need outputs of up to 200 watts for this level. The performance specifications for volume levels of loudspeaker systems are not standardized. However, the following measured values ​​are required for a reliable statement:

  1. (Input) sensitivity or characteristic sound pressure level : This value expresses the volume or sound pressure level the system generates at 2 volts or 2.83 volts at a distance of one meter (for example: 90dB / 2V / 1m).
  2. "Continuous Power": This value expresses the maximum volume the system can produce in continuous power. The information is given in dB.
  3. Final sound pressure, "Maximum Power" or "Peak value": This value expresses the maximum level the loudspeaker system can generate before it is destroyed. The information is given in dB.

For a realistic performance specification, the transmission range is required in addition to these measured values. A broadband loudspeaker (full range) that has to transmit all audible frequencies (20 Hz - 20 kHz) has to provide significantly higher performance than, for example, a loudspeaker due to the high loads involved in generating the bass frequencies. B. a PA high-performance top (mid-high speakers approx. 150 Hz - 20 kHz).

Since the abbreviation Hi-Fi is not protected, compliance with EN 61305 must be checked in each individual case. Information such as music performance and, above all, maximum performance or “ PMPO ” are not precisely defined.

With so-called RMS power, a power amplifier or loudspeaker must withstand a broadband test signal consisting of pink noise for 10 minutes without damage and in compliance with EN 61305. This signal cannot be compared with music signals ( crest factor typically greater than 12 dB) and therefore only allows a statement to be made about the electrical load capacity of the loudspeaker or the output stage. Most of the time the loudspeaker reaches its mechanical maximum load, especially in the low frequency range, under the maximum electrical load, above which the loudspeaker membranes can no longer follow the (music) signal. The RMS power therefore only permits statements about the maximum level of a loudspeaker to a limited extent. In addition, the electrical load capacity of a loudspeaker says nothing about its sound quality (s).

In " Dolby Surround systems" or " Home Theater " or "Cinema" systems, the left and right power amplifier / loudspeaker combination (possibly including subwoofer ) should meet the Hi-Fi standard. Weaker guidelines apply to the rear speakers.

Current quality features

At present, EN 61305 no longer plays a quality-determining role in the hi-fi market, as most recording devices, sound carriers and playback devices far exceed these requirements. Only radio alarm clocks, simple so-called compact systems in the lower price segment and many car radios and all hearing aids still do not guarantee hi-fi-compatible playback even today.

Today it is expected of a good audio system for music playback that its specified data significantly exceed the Hi-Fi values. This applies to the frequency transmission range, which should approach the audible limit of around 20 kHz, but also to the distortion factor and the signal-to-noise ratio .

While amplifier technology is largely mastered today in terms of frequency response , noise , signal-to-noise ratio , crosstalk and distortion factor, the loudspeakers , combined with room acoustics , are still a weak point today. Small loudspeakers basically have a problem with the bundled radiation of low-mid frequencies, which is problematic if you want to integrate them into the room acoustics. Loudspeakers have the worst frequency response and by far the highest distortion factor of all components.

Ground loops or ground loops and interference from digital devices often destroy the good signal-to-noise ratio values ​​of individual components.

Individual evidence

  1. ↑ "Hi-Fi", paragraph "Pronunciation". In: Duden online . Retrieved on December 15, 2016 (audio samples from the ARD pronunciation database ).
  2. ↑ Standardized measuring methods of magnetic sound technology

literature

  • Thomas Görne: Sound engineering. 1st edition Carl Hanser, Leipzig 2006. ISBN 3-446-40198-9
  • Gustav Büscher, A. Wiegemann: Little ABC of electroacoustics. 6th edition Franzis, Munich 1972. ISBN 3-7723-0296-3
  • Helmut Röder, Heinz Ruckriegel, Heinz Häberle: Electronics. 3rd part. Communications electronics. 5th edition. Europa-Lehrmittel, Wuppertal 1980. ISBN 3-8085-3225-4

Web links

Wikibooks: Car HiFi  - learning and teaching materials