Hello everybody! I'm new at this forum. Javi from Spain (sorry about my english 😅)
Firstly, I find that if you go with a mono setup (using just one l2t) you really don't need to use the L6 link connection... So if you use the XLR output or the 1/4 unbalanced output you will change manually the speaker mode setting.
Anyway, if you want to use for some reason the L6 link, I think that you just have to re-save your patch with the speaker mode you want.
Finally, the most important thing about this that I want to tell you is that you can trust in the floor monitor mode as a good reference of what you are sending to FOH.
When the Lt2 is on the floor, the sound of your patch gets some lower frecuencies that are garbage in your sound. The floor monitor mode simply cuts these lower frecuencies giving you a good representarion of what you are sending.
In fact, if you use the PA/ reference mode with the lt2 on the floor, you will not have a true reference of what you are sending to the PA of the Venue because what you will be sending won't have these lower frecuencies.
