I had to initiate qjackctl for every operation I did unto Audacity- then using the jack audio playback in the audacity I converted the wav to Mp3, and it worked fine. Audacious will also play through jack if you go into the settings, and the wav will play. Ardour claims that “all audio I/O is processed through jack”. So the steps I took= intitiating Qjackctl, I made sure all setting matched all settings in Ardour audio setup and export. I played wav file through Audacious using Jack audio playback setting. This gave me the idea to try it on Audacity, and doing that I exported the wav file to Mp3.
I had to intiate Qjackctl for every process I did until Audacity, and kept it running for all processes I did, by using the jack server playback setting on all processes of playback.
As for the problem which seablade has mentioned in his post from April 4th, 2011: maybe it’s a solution to use Audacious (http://audacious-media-player.org/) for monitoring: it’s a comfortable and small open source software which cooperates nicely with Jack.
I use Audacious everytime when I want to listen quickly to an exported *.wav file while keeping Ardour open - and also afterwards to listen to *.mp3 files which I made with Soundconverter (http://soundconverter.org/).
Michael