I recently started fooling around with GarageBand for the first time, and even though it’s presumably not a product aimed at very serious musicians, it’s quick and easy to make some nice sounds. Here are a couple of ambient pseudo-improvisations I made (they’re more or less improvised, although since they are each several tracks, they weren’t made 100% in real time).
The first one is made from a couple of GarageBand’s built-in keyboards and synths, and has a “theme song to a sci-fi show” vibe to it:
The second one is built in a few layers of repetition, and has a very earnest vibe to it. It’s just a recording or two of me playing the piano, so I was only using GarageBand for mixing: