Since the dawn of the 20th century, recordings have come to dominate our musical experience. From at least the 1920s until the present day, the principal way jazz musicians learned their craft was through recordings. Today, the first experience most children have with any music is most often through recordings in toys or on TV. Recordings themselves are now an integral part of many new compositions -- hip-hop, based originally on sampled LPs, simply wouldn't exist without them.
More, recordings have broadened the time window of the culture. Where the era of Brahms would have heard only the musicians and performers alive at that time, we routinely hear the music of performers who died a half century or more ago. Performances by John Lennon (died 1980), Louis Armstrong (died 1971), Billie Holiday (died 1959) and conductor Leopold Stokowski (died 1977), to name just a few, are all still enormously popular through recordings.
Where Brahms' history is mostly darkness, recordings light up the lives of more contemporary composers like Time Square marquees turn New York City night into day: Frank Zappa, John Luther Adams, Elliott Carter, John Adams, Philip Glass, Pauline Oliveros -- all of them supervised recordings of their music; all of them appear on recordings in interviews.
For the future's history buffs, a John Cage appearance on What's My Line? in 1960, currently available on YouTube, holds enormous value, placing the avant garde composer's radical music in the context of a live game show's everyman audience. Other recordings reveal him participating in performances, enjoying a laugh with friends, talking extensively, off the cuff, about his thoughts on music and spirituality.By contrast, even a well-documented life, like that of Brahms, is a black hole to us. As that process escalates, with products like Google Glass and a growing acceptance of surveillance culture, less and less of history will be dark. In 2189, 300 years after Brahms walked away from the Edison cylinder recording and returned to his relative darkness, the lives of our children and our grandchildren will appear to historians transparent, as open to investigation as their own.