High Fidelity

High Fidelity [ ˌ haɪ̯fɪdɛləti: ] (English, high (sound) loyalty ' or hi -fi [ haɪ̯fɪ ], also [ haɪ̯faɪ̯ ] ) is a quality standard in audio engineering.

Originally, the guidelines were established in the 1960s in DIN 45500. This DIN standard 1996 replaced by EN 61305, which contains only method of measuring and specifying the performance parameters, but no minimum requirements, as the once standard requirements are now no longer seen as a technical challenge.

Technology

The human ear can not hear sounds from about 16 Hz to 20 kHz, the listening area is, however, individually different, an adult has an average range of hearing of about 20 Hz to 16 kHz. In tones between 2 kHz and 5 kHz, the human is most sensitive, so that differences in pitch are also best performed here. So wrote the DIN 45500 for magnetic sound a linear frequency response from 250 Hz to 6300 Hz for hi-fi home studio equipment before, with a tolerance was allowed to 5 dB. For studio devices were considered in accordance with DIN 45511 stricter rules: Only a tolerance was in a frequency range from 80 Hz to 8000 Hz allowed by 3 dB.

The RMS power can not allow any conclusions on the achievable volume. While large horn speaker with 1 watt already reach levels of 105 dB, need a lot of hi-fi speakers for this level of performance of up to 200 watts. The performance data for volume of speaker systems are not standardized. However, the following measurements are needed for a reliable statement:

For a realistic performance data in addition to the transmission range is required for these measurements. A full range speakers ( full range), which must transfer all audible frequencies (20 Hz - 20 kHz) must offer higher performance than, for example because of the high burden for the generation of the bass frequencies a PA high-power top (mid- high speakers 150 Hz - 20 kHz).

Since the abbreviation Hi -Fi is not protected, the compliance with EN 61305 must be checked in particular cases. Information, such as maximum power, music performance or " PMPO " are not precisely defined.

In the so-called RMS power of an amplifier or a speaker must have a broadband test signal consisting of pink noise, 10 minutes survive without permanent damage and in compliance with EN 61305. This signal is with music signals ( crest factor typically greater than 12 dB) were not comparable and therefore makes a statement about the power handling of the speaker, or the amplifier. Usually, however, the speaker just in the bass range already achieved under the maximum electrical load its mechanical maximum load from the can no longer follow the (music) signal speaker membranes. The RMS power so permits only provide limited information about the maximum level of a speaker. In addition, the electrical load of a speaker says nothing about its sound quality (s).

When " Dolby surround sound systems " and " home theater " - or "Cinema" systems, the left and right power amp - speaker combination (possibly including subwoofer) should meet the Hi -Fi standard. For the rear speakers weaker guidelines.

Current quality characteristics

Currently, takes the EN 61305 in Hi- Fi market no longer a quality-determining role, since most recording devices, audio recordings and playback devices exceed these requirements by far. Only radio alarm clock, simple so-called compact plants in the lower price segment, and many car radios ensure even today no Hi- Fi -compliant playback.

It is expected today from a good audio system for music playback that their specified data surpass the hi-fi values ​​significantly. This affects the frequency pass band, which should be as close to the hearing threshold of about 20 kHz, but also the harmonic distortion and the signal to noise ratio.

While the amplifier technology is largely dominated today with regard to frequency response, noise, signal to noise ratio, crosstalk and distortion, are the speakers connected to the room acoustics, still a weak point. Small speakers 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. Speakers have the worst frequency response and by far the highest distortion of all components.

Ground loops or ground loops and the noise of digital devices often negate the good Störabstandswerte individual components.