The heyday of prerecorded reel tapes was the mid-1960s, but after the introduction of less complicated cassette tapes and 8-track tapes, the number of albums released on prerecorded reel tape dropped dramatically despite their superior sound quality. By the latter 1960s, their retail prices were considerably higher than competing formats, and musical genres were limited to those most likely to appeal to well-heeled audiophiles willing to contend with the cumbersome threading of open-reel tape. The introduction of the Dolby noise-reduction system narrowed the performance gap between cassettes and open-reel, and by 1976 prerecorded open-reel offerings had almost completely disappeared, even from record stores and audio equipment shops. Columbia House advertisements in 1978 showed that only one-third of new titles were available on reel-to-reel; they continued to offer a select number of new releases in the format until 1984.