
1) At turbo-prop speed 2) Below Mach 1 3) Infrasonic 4) Not like an SST
Found on
https://www.crosswordclues.com/clue/subsonic
[Younha EP] Subsonic is the third extended play by South Korean singer Younha. The album was released on December 6, 2013 and is her eleventh non-compilation release. ==History== ===Creation and promotion=== The mini album was part of a series of albums Younha released following a self-imposed hiatus due to panic disorder. It was also the t...
Found on
http://en.wikipedia.org/wiki/Subsonic_(Younha_EP)
[media server] Subsonic is an open source, web-based media server. Because Subsonic was written in Java, it may be run on any operating system with Java support. Subsonic supports streaming to multiple clients simultaneously, and supports any streamable media (including MP3, AAC, and Ogg). Subsonic also supports on-the-fly media conversion ...
Found on
http://en.wikipedia.org/wiki/Subsonic_(media_server)

Less than the speed of sound.
Found on
http://www.daviddarling.info/encyclopedia/S/subsonic.html

Type: Term Pronunciation: sŭb-son′ik Synonyms: infrasonic
Found on
http://www.medilexicon.com/medicaldictionary.php?t=85998

[
adj] - (of speed) less than that of sound in a designated medium
Found on
http://www.webdictionary.co.uk/definition.php?query=subsonic

Having a speed less than that of sound in a designated medium. See also: Hypersonic, Hypervelocity, Mach Number, Sound, Supersonic.
Found on
https://www.encyclo.co.uk/local/20687
adjective (of speed) less than that of sound in a designated medium; `aircraft flying at subsonic speeds`
Found on
https://www.encyclo.co.uk/local/20974

noting or pertaining to a speed less than that of sound in air at the same height above sea level. · infrasonic.
Found on
https://www.infoplease.com/dictionary/subsonic
No exact match found.