Nowadays is easier than ever for an artist release an album: through a label (one of the three major labels, their subsidiaries or an independent label), release founded by crowdfunding as Kickstarted, release directly through Bandcamp or Soundcloud, or even release their music via YouTube.
While in the old times the first filter was the team in the labels which do this selection, something like headhunters, choosing who will release an album and who will not, with this freedom to record and release albums, there are lot of music, lot of artists, lot of new releases every day, week, month, year but… how can we distinguish between the good music and the very special music that will remain for years and years? That’s the work for the filters in music.
The first and traditional filters are the music critics. There are sites as Pitchfork, Rolling Stone, Indie Shuffle or we can find relevant music critics writing in the newspapers (as Neil McCormick), writing books (as Robert Hilburn, Robert Christgau and Alex Ross) or in blog sites. Their relevance is according to their trajectory, knowledge, experience to review the albums.
The second type of filters in the music are the music rankings, for example Billboard. In the particular case of Billboard, their “Hot 100 formula targets a ratio of sales (35-45%), airplay (30-40%) and streaming (20-30%)”. (You can check it out the full article about their methodology here: http://www.billboard.com/articles/columns/ask-billboard/5740625/ask-billboard-how-does-the-hot-100-work )
The third are the music prizes, as the Mercury Prize in England, the Polaris in Canada or the Grammy in the United States. In general, the people who choose the winners are people professional, deeply involved in the music industry.
Finally, there are other useful tools, as the music recommendations according to our profile using big data, as in the case of Spotify, Record Bird or Apple Music. But in this cases, more than filters are tools to know bands/musicians according to our likes, using algorithms.
As we said earlier, originally the first filters was the headhunters of the labels and the fame of the label was behind of the group/artist that gonna be released. Nowadays, we need more filters to find the very special music, and that opens a lot of possibilities in the music industry.