I would put the oak in, if anything it sound like it might help with diffusion. When you build a room with parallel walls and everything is the same on both sides you are going to have to deal with the echo it will create. Plus wood sounds better than other building materials. The best sounding rooms I have been in are largely sided with wood.
Oak ledge in dedicated room?
I am finishing my lower level and my dedicated listening room will be smallish, (11' x 18' x8"). I have the option of having a 6 inch oak ledge four feet up from the floor the full length of the outside long wall. The ledge would asthetically look great. I could forgo the ledge and only have a straight up wall if the ledge would degrade room acoustics, (ie, nodes, standing waves, or whatever)? I am already planning on using dedicated lines, insulation, sound channel. Any input on whether to use the ledge or any other suggestions would be greatly appreciated. Thank you in advance for your time.