Bitrate. This setting selects the desired compression quality of the music you wish to download. This is measured in Kbps (Kilobytes per second), selecting a lower bitrate has 2 consequences The first being that soundquality is reduced, the second being that the file size is smaller, e.g. a 128Kbps music file would be 1/2 the size had it been compressed at 64Kbps. Depending on your Internet connection you try to select an appropriate Bitrate, i.e. If you are on a slow Internet connection you should try downloading lower bitrate music as it will download faster, while this on fast connections should go for higher bitrate music as the sound quality is better & they should be able to download it relatively fast.