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.
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.
I agree. Varying its height and depth here and there might help too.
Sorry, the ledge I was describing is only 1" X 6" horizontal oak with the sheetrock set back above the ledge and there will be sheetrock below the ledge. Most of the room will be sheetrock, although it may be 5/8" thick.
I would go with the ledge. It will likely help rather than hurt your acoustics plus as it will look great.
I'd worry a lot more about the parallel walls away from the proposed ledge. Suitable treatment elsewhere should improve your sound, while the ledge by itself, as already suggested by Ejlif, will, if anything, help a little, not hurt. I always recommend reading F. Alton Everest, "Sound Studio Construction on a Budget" or "Master Handbook of Acoustics" (edition later than the first), and will do so again. If you let him guide you, you'll end up with a room that's both aesthetically and acoustically pleasing.