forever changed the way music was heard and listened to. Opera houses, concert halls, and clubs continued to produce music and musicians and singers continued to perform live, but the power of radio allowed bands, ensembles and singers who had previously performed only in one region to become popular on a nationwide and sometimes even a worldwide scale. Moreover, whereas attendance at the top symphony and opera concerts was formerly restricted to high-income people in a pre-radio world, with broadcast radio, a much larger wider range of people, including lower and middle-income people could hear the best orchestras, big bands, popular singers and opera shows. The "record industry" eventually replaced the sheet music publishers as the music industry's largest force. A multitude of record labels came and went. Some noteworthy labels of the earlier decades include the Columbia Records, Crystalate, Decca Records, Edison Bell, The Gramophone Company, Invicta, Kalliope, Pathé, Victor Talking Machine Company and many others. Many record companies died out as quickly as they had formed, and by the end of the 1980s, the "Big six" — EMI, CBS, BMG, PolyGram, WEA and MCA — dominated the industry. Sony bought CBS Records in 1987 and changed its name to Sony Music in 1991. In mid-1998, PolyGram Music Group merged with MCA Music Entertainment creating what we now know as Universal Music Group. Since then, Sony and BMG merged in 2004, and Universal took over the majority of EMI's recorded music interests in 2012. EMI Music Publishing, also once part of the now defunct British conglomerate, is now co-owned by Sony as a subsidiary of Sony/ATV Music Publishing. As in other industries, the record industry is characterised by many mergers and/or acquisitions, for the major companies as well as for middle sized business (recent example is given by the Belgium group PIAS and French group Harmonia Mundi). Genre-wise, music entrepreneurs expanded their industry models into areas like folk music, in which composition and performance had continued for centuries on an ad hoc self-supporting basis. Forming an independent record label, or "indie" label, or signing to such a label continues to be a popular choice for up-and-coming musicians, especially in genres like hardcore punk and extreme metal, even though indies cannot offer the same financial backing of major labels. Some bands prefer to sign with an indie label, because these labels typically give performers more artistic freedom. Rise of digital