In the 19th century, one of the key ways that new compositions became known to the public was by the sales of sheet music, which middle class amateur music lovers would perform at home on their piano or other common instruments, such as violin. With 20th-century music, the invention of new electric technologies such as radio broadcasting and the mass market availability of gramophone records meant that sound recordings of songs and pieces heard by listeners (either on the radio or on their record player) became the main way to learn about new songs and pieces. There was a vast increase in music listening as the radio gained popularity and phonographs were used to replay and distribute music, because whereas in the 19th century, the focus on sheet music restricted access to new music to the middle class and upper-class people who could read music and who owned pianos and instruments, in the 20th century, anyone with a radio or record player could hear operas, symphonies and big bands right in their own living room. This allowed lower-income people, who would never be able to afford an opera or symphony concert ticket to hear this music. It also meant that people could hear music from different parts of the country, or even different parts of the world, even if they could not afford to travel to these locations. This helped to spread musical styles.