Turning right puts more load on the outside wheel, the left one. Try removing and inspecting the left wheel bearings, both inside and outside. I suspect you're going to find some flat spots on an inner wheel bearing. They get progressively worse as the bearing deteriorates. I chased a noise like that on a Ford Explorer for two years, until it finally got loud enough to isolate the noise down to one specific bearing. Even then, I had to take the bearing apart, as the noise was caused by roughness on the inner race, under the tapered rollers!
Jerry