把音樂廳搬回家——現代音頻技術發展的標準化軌跡

文/五花肉

把音樂廳搬回家，隨時享受美妙的音樂，是人類自發明留聲機以來的100多年間，孜孜以求的夢想。隨著音頻技術標準的不斷發展，從最初的雙聲道到如今的八聲道，尋常百姓的樸素音樂夢想已經觸手可及。

Enjoying concert at home is the dream that human have pursued since the phonograph was invented 100 years ago. From the initial dualchannel to eight-channel till now, thanks to the development of the audio standards, the music dream of ordinary folks has come true.

雙聲道—高保真的起點Dual-channel Stereo—Origin of Hi-Fi

1957年，美國無線電公司（RCA）率先將雙聲道立體聲唱片投入商用，通過左、右兩聲道間錄制成電平不同的聲音信號，制造出聲源在兩路揚聲器之間移動的感覺，產生立體聲效果，廣受市場好評，雙聲道技術自此迅速得到普及。

In 1957, RCA Corporation initially introduced the dual-channel stereo discs into commercial application. Different electrical levels of audio signal were recorded in left and right channels to create the stereo sound effect. The stereo technology widely acclaimed in the market and rapidly grew popular in the world.

為了評價立體聲系統的質量，Hi-Fi（High-Fidelity俗稱高保真）標準應運而生：要求音像制品頻率響應達到40Hz～16kHz的均勻放聲，不均勻度不大于5dB，非線性失真小于0.3%等。

In order to evaluate the quality of stereo sound system,high- fi delity ( Hi-Fi ) was developed, which requires that frequency response of audio and video products reach 40Hz-16kHz sound reproduction evenly;unevenness be no more than 5dB and non-linear distortion be less than 0.3%, etc.

多聲道—身臨其境的體驗Multi-Channel—Immersive Experience

到了1977年，美國杜比公司在雙聲道的基礎上，成功研發出四聲道的杜比立體聲技術（Dolby Stereo）。杜比公司把左、中、右、環繞的四個聲道信號編碼合成為雙聲道，在播放時將其解碼還原成四聲道信號。通過這種技術，即使是普通的家庭音響設備，也能讓人感受到身臨其境的音樂體驗。

In 1977, Dolby Laboratories Inc developed multichannel technology——Dolby Stereo based on dualchannel sound system. Dolby technology encoded four original channels, namely left; center; right and surround into two channels and decoded the two channels into four channels in performance. Such a multi-channel audio technology was applied into family audio system, which created the immersive music experience at home.

一時間，杜比標準成為了衡量音響設備質量的重要依據，通過杜比認證的產品，也成為了優質音響設備的代名詞。

Dolby standards became important criteria to evaluate the quality of audio equipment at that time. Products certified by Dolby Inc symbolized superior acoustic fi delity.

數字時代—音頻標準大發展Digital Era—Great Leap in Audio Standards

數字時代的到來，再次加快了音頻標準發展的步伐。

The advent of digital era accelerated the development of audio standards.

1991年，杜比公司與日本先鋒公司共同研發出杜比AC-3音頻標準。該標準使用數碼壓縮編碼技術將6個完全獨立的聲道進行數字化處理，使用戶獲得更加清晰的音樂細節。兩年之后，AC-3標準被正式認定為美國高清晰度電視的音頻編碼、解碼標準。

Dolby AC-3 was created by the joint efforts of Dolby Inc and Pioneer Corporation in 1991. This standard encoded six separate channels signal into digital data, which improved sound quality. Two years later,AC-3 was officially recognized as the audio coding and decoding standard for American high-definition television (HDTV).

此后，另一家美國公司發布了DTS標準，通過更高的數據流量和更低的數字壓縮比，進一步提升了聲音的還原度和清晰度。杜比和DTS兩家公司研發的8種音頻規格,也成為了目前視聽應用的主流音頻標準。

Later, DTS Corporation developed DTS standard.Compared with Dolby standard, DTS standard boasted a higher fidelity with more data flow and lower compression ratio. Eight audio standards developed by Dolby Laboratories and DTS respectively have been the mainstream audio standards in audio-visual applications by far.

結 語 Conclusion

升級音頻技術，引領產業方向，音頻設備產業的每一次重要革新和市場飛躍，都離不開標準的推波助瀾，讓原本奢侈專享的“音樂廳”，真正飛入了尋常百姓的客廳，為人類100多年的音樂夢想附上了圓滿的注腳。

Standards make great contribute to every step of audio technology innovation. Thanks to the audio technology standardization, it makes possible to get experience of concert and cinema at home. Music dream in 100 years of ordinary folks eventually has come true.