Linux version with FM (including stereo and RDS) and Low Latency audio:
http://www.stereotool.com/download/ster ... ETA724-021
Note: To use for FM, set the Jack samplerate to 192000 and the Stereo Tool sample rate too! (I still have to write code to detect the Jack sample rate and use it, and disable the current sample rate dropdown menu).
Also, make sure that buffer sizes are *below* 1 second (AT one second is already bad).
I hear a clicking sound in the FM output (not always, seems to be related to stereo sounds). Not sure yet what's causing this, could be that my CPU cannot handle it or there's a real bug somewhere (so I'm curious if others hear it too). It might also be related to the issue that Bojcha reported - I will try to fix that first and see if it fixes the clicking sound.
Hint: To use with realtime priority, you need to start jackd or qjackctl as superuser (using sudo). If you do that, you also need to start Stereo Tool with sudo or it cannot connect to Jack!