The main focus of ambient music is on sound and space rather than melody and form and below are some ambient music reviews. Ambient music is a style that can be used not only as music to listen to, but is also great as background music. Slowly evolving sounds and repetition are the main characteristics of ambient music. In 1978, Brian Eno released Ambient 1, Music for Airports. The album was released at the pick of disco music and went pretty much unnoticed. The album, however, has grown in importance every year since. Ambient 1 was a beautiful manifesto. It is a collection of timeless soundscapes, all beautifully packaged. It also marks the birth of ambient music. In his liner notes, Eno places ambient music as an alternative to Muzak. Composers but also serious listeners did not pay too much attention to Muzak as, according to Eno, it was too lightweight and dull. “Ambient music” was a term created by Eno to show the difference between his music and background music available at that time. The most important thing is that Eno wanted to create music that would make people to think. He achieved this by creating beautiful yet not attention demanding music. Eno writes, “Ambient Music must be ignorable and in the same time interesting, and also must be able to accommodate many levels of listening attention”. Eno's Ambient series contains a set of four works that cover a lot of territory. His four piece Ambient 1, Music for Airports is the aural analogue of a mobile. Sounds move slowly by the listener in what looks like a random pattern, but later combine to make subtle variations. The composer Harold Budd was working with Eno when he was creating Ambient 2, The Plateaux of Mirror. The album is a collection of slow and soft piano work. Eno experiments with different electronic effects, giving his piano different sound. Ambient 3, Day of Radiance, exhibits another side of Eno’s ambient idea. Day of Radiance is a collaboration with Laraaji, and has two groups of pieces. The first group are dances with hammered-dulcimer upbeat music. The remaining pieces are slow and reflective. The darkest of Eno’s work is Ambient 4, On Land. It is mostly electronic, but Eno added also a bit of treated electronic sound. Ambient 4, On Land consists of the sounds that are not easy to recognize – you will have a difficulty to know if you are hearing an instrument ,treated recording or maybe an electronic sound.  On Land and Music for Airports share the same approach, however the final results are very different. On Land is a collage of mysterious, even scary sounds, that create a sense that you're in an alien landscape. While Brian Eno has been the most influential composer of ambient music, many other musicians have explored this area, too. There is a great number of ambient music podcast sites on the internet, which allow you to download podcasts to your iPod for free. Nowadays, ambient music is divided into many sub-genres such as ambient techno, ambient trance or dark ambient. Among active ambient artists you will find Eluvium, Carbon Based Lifeforms and UtopiaXO.