SoundFocus: SoundFocus is “the world’s first music player that tunes to your hearing,” according to its creators, led by SoundFocus CEO Alex Selig, who himself suffers from hearing impairment.First, you test your hearing acuity, roughly speaking, in three zones — lows, mids, and highs. In addition to everything on your phone and in your Apple iTunes Match account (although it can’t apply its EQ to the cloud-stored songs), SoundFocus includes artist radio stations using Spotify’s catalog, if you’re a premium subscriber, programming the artist stations using technology from The Echo Nest (publisher of Evolver.fm). You also get access to all your Spotify on-demand tracks. SoundFocus can work its EQ magic on Spotify songs, just not on iTunes Match songs, so we recommend turning off iTunes Match in your iOS settings if you’re going to use this app as your main player. [Free]