From the ancient Greek theater, through the dawn of the Renaissance, beyond the development of Shakespearean theater, to the Broadway theater boon in the 1920s, sound reinforcement within the theater remained virtually unchanged. Through Broadway's Golden Age, directors and producers relied on architectural acoustics to carry sound throughout the theaters. This is not surprising given that most of the theaters were built in the early 1900s, before the invention of any electric sound reinforcement technology. Moreover, early attempts at amplification in the 1940s yielded dismal results. Eventually, the maturation of the integrated book musical and the invasion of the rock musical in the late 1960s demanded more than architectural acoustics alone could provide. Abe Jacob, the sound designer of Hair and Jesus Christ Superstar, led the efforts to create a modern approach to sound design. Relying on his rock-and-roll touring experience and the introduction of technological advancements within the recording industry, Jacob and others forged a modern approach to sound design specifically within the framework of the Broadway musical, which helped restore the fading industry of the Broadway musical in the late 1960s. These new approaches served well the human irony and concept musicals of the 1970s by Sondheim and other emerging composers. Sound design was critical to the successful mounting of the mega-musicals of the 1980s (Cats, Les Miserables, Starlight Express, The Phantom of the Opera, Miss Saigon, etc.). Now, modern day composers collaborate early in the creation process with sound designers and create original works with the power of modern sound design in mind, such that today, sound design is a fundamental design discipline employed in every Broadway musical–from the initial show concept conversations all the way through opening night.