I have been trying to figure this out for a few weeks. I am currently running Crunchbang linux on my laptop and I use it to record music and play guitar through Guitarix. To run Guitarix I need to use Jack audio server. When Jack is running I can't playback Youtube videos, which I need to do to play along to lessons.

I have tried:

1. playing back youtube in VLC which I can't get to work
2. Jack Flash plug in. I found some threads about this from 2009 and the plug in doesn't install on Crunchbang.
3. Downloading youtube videos to playback in VLC with smtube and youtube-dl and can't get either to install on Crunchbang.

Any thoughts on how to get this working?

since I myself have never need jack, I can not give anything concrete

However I do hope the following link helps you out

http://jackaudio.org/pulseaudio_and_jack


I have made an assumption that pulse works well for you,I have seen people complaining about pulse , I guess that is the nature of the interwebz , pulse works well for me

My solution to this was to run Linux mint on my laptop. I am able to run guitarix app through jack and playback YouTube videos in vlc player with the jack plug in. Same work flow wouldn't work in crunchbang, Debian or fedora which I also tried.