HQ TTS: very High Quality Text To Speech resulting in a very natural and pleasant-sounding voice which has never been closer to the human speaker.
HD TTS : very High Density Text To Speech offering the best density/quality compromise of the market
HQM TTS: HQ Medium Quality: Same voices as HQ voices, but with a lower audio encoding in order to reduce size on disk.
LF TTS : Low Footprint version of our HQM Text To Speech voices (~25MB/voice)