That's roughly the equivalent of an mp3 encoded in 320kbps.
On Spotify, the usual streaming quality is 160 kbps. When users turn on the "high quality streaming" option, the stream rate jumps to to 320 kbps. It's unclear if Soundcloud's offering uses additional compression or other technology or essentially mirrors Spotify
Tracks uploaded as lossless or at a high bitrate will be available for streaming on SoundCloud in "high quality."