 Cassette-based machines could not provide the same audio quality as reel-to-reel machines, but served as a useful tool for professional and semi-pro musicians in making song demos.The Portastudio had a revolutionary effect on the emerging punk rock genre, because it enabled young bands to make recordings without signing to a record label.In the early years of punk, many bands self-produced their own recordings and sold them at gigs and by putting advertisements in underground zines.