OK Plesse redo all Doings in the truss rod!
Probably the string is going to die.....
Check if the string is in tune
First with your ears and then finetuning with the Tuner (if you use one)
If you get the string in tune, we'll have to look at the hardware

So, the beauty of Emmett truss design is that it both pulls or pushes. If you have looosened the nut all the way and you still have an arch, then you can spin the nut all theway to the end of the threads and then apply tension to it to "push" out the arch.

This is covered at 5:20 in the video linked above.

Another possibility for your problem though, is that your string could be damaged. run your fingers along the string and see if you can feel a divot or bend in the string itself. If that happens, you will need to change the string.

Hope that helps.

The string is in tune and I have returned the truss rod to its' original position.

Do you still have the poor sound?
Does the string hold the tuning during playing?
If yes take a look at both sides of the string if all parts are tight. (You wrote,that you transported the stick a lot)
Eventually the tuner, the saddle screw or the slideblocks is loose and not in the correct Position.

Thanks all of you for your help and knowledge. The problem was the string. Fortunately I had a backup. After I replaced the string all was normal again. Thanks again everyone!