trying to get my head around which do and which don't. Ibanez site just gives "standard truss rod" in the spec page for the new ones. Also what about the bolt on models ? Do any of the 4 string model have a dual rod set up ? Do the 2 dark insets running down on the back of the neck mean 2 truss rods? Background- I have owned and played a 5 string BTB since 2005. My main bass these days. I have been trying to set up another bass for DGCF as "D" has become the new" E " in my band, mainly for vocals and my guitar player also plays extremely hot slide in D. ATM I have 2 D basses on the go. I have gone to a heavier 110 on the bottom string as standard is too floppy. My trusty old 74 jazz bass has taken to it extremely well and feels right action and tension wise. I have also set up an Ibanez SDGR with the same gauge strings but it just don't like it though I have been slowly tweeking it and getting it better. Sounds killer compared to the fender but very tight feeling to play. I would like to get my hands on a BTB 4 with the dual truss rods ( if there is such an animal) I have seen pictures on ebay of 4's with the dark stripes on the back of the neck hence my earlier question. Any insights would be appreciated.