Tidal has several big name backers Some of the biggest names in entertainment have re-launched the music subscription service Tidal, which they are billing as the first artist-owned platform for music and video.
At an event in New York on Monday, Madonna, Beyonce, Kanye West, and 13 other performers announced they had become co-owners of Tidal.
The service launched last October, but was recently bought by rapper Jay-Z.
It is hoping to compete with the likes of Spotify, Deezer and Google Play.
However Tidal offers 25 million music tracks, fewer than the 30 million offered by many rival services.

As well as a standard subscription for $9.99 a month, Tidal offers a "high fidelity" option for $19.99, which claims to deliver better sound quality.

Alicia Keys said they would make history Singer Alicia Keys spoke on behalf of the artists as they all lined up on stage at Skylight at Moynihan Station in Manhattan.
Describing the event as a "graduation", she said the artists hoped Tidal would alter musical evolution.
"So we come together before you on this day, March 30th, 2015, with one voice in unity in the hopes that today will be another one of those moments in time, a moment that will forever change the course of music history."
Their mission, she said, goes beyond commerce and technology.
"Our intent is to preserve music's importance in our lives,'' she said.