Yes, I have tried one. I have owned/still own a fair amount of PJB kit. The Double 4 can be deceiving, because you can place it close to you, even at ear level due to its small size and hear yourself quite well. However, it has very limited projection at any distance. It just doesn't move enough air. I used to have a Flightcase and that didn't do the job in anything other than very quiet, smallish rooms, so a Double 4 certainly won't. As Hiram says above, you need at least a Suitcase in any real-world situation (I use my 4B - essentially a Suitcase minus amplification - with a head for smaller jobs).