High fidelity

: High Fidelity is also the title of a book by Nick Hornby and a film directed by Stephen Frears, based on Hornby's book.

Semblance of Realism

When high fidelity was limited to monophonic sound reproduction, a realistic approximation to what the listener would experience in a concert hall was limited. Researchers early realized that the ideal way to experience music played back on audio equipment was through multiple transmission channels, but the technology was not available at that time. It was, for example, discovered that a realistic representation of the separation between performers in an orchestra from an ideal listening position in the concert hall would require at least three loudspeakers for the front channels. For the reproduction of the reverberation, at least two loudspeakers placed behind or to the sides of the listener were required.

Related Topics:
Monophonic - Concert hall - Researchers - Technology - Orchestra - Reverberation

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Stereophonic sound provided a partial solution to the problem of creating some semblance of the illusion of performers performing in an orchestra by creating a phantom middle channel when the listener sits exactly in the middle of the two front loudspeakers. When the listener moves slightly to the side, however, this phantom channel disappears or is greatly reduced. An attempt to provide for the reproduction of the reverberation was tried in the 1970s through quadraphonic sound but, again, the technology at that time was insufficient for the task. Consumers did not want to pay the additional costs required in money and space for the marginal improvements in realism. With the rise in popularity of home theatre, however, multi-channel playback systems became affordable, and consumers were willing to tolerate the six to eight channels required in a home theatre. The advances made in signal processors to synthesize an approximation of a good concert hall can now provide a somewhat more realistic illusion of listening in a concert hall.

Related Topics:
Illusion - Quadraphonic - Consumers - Money - Home theatre - Signal processors

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In addition to spatial realism, the playback of music must be subjectively free from noise to achieve realism. The compact disc (CD) provides at least 90 decibels of dynamic range, which is about as much as most people can tolerate in an average living room. This therefore requires the playback equipment to provide a signal-to-noise ratio of at least 90 decibels. Many people can hear up to, at most, 15 kHz and for a few, up to 20 kHz. There is relatively little music below 50 Hz, loud bass below 30 Hz is rare, music below 16 Hz is almost non-existent, and music below 5 Hz is probably non-existent. (Incidentally, the cannons in Telarc's recording of Pyotr Tchaikovsky's 1812 Overture are said to go down to 5 Hz.) The equipment must also provide no noticable distortion of the signal or emphasis or de-emphasis of any frequency in this frequency range. Except for spatial realism, good modern equipment can easily satisfy all of these requirements at a relatively moderate cost.

Related Topics:
Music - Compact disc - Decibels - Dynamic range - Living room - Signal-to-noise ratio - KHz - Bass - Cannons - Recording - Pyotr Tchaikovsky - ''1812 Overture'' - Signal

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