Within a frame work of two channel audio, it is not simply timing information that is important, but relative timing information, i.e. the time difference between arrival at both your ears. To that end, a large baffle will not impact the primary wave front timing differential between a signal from one speaker to both your ears. Maybe you meant something else?
Time and Phase. Study how the highly evolved ear brain function to localize food and threat sounds and you will understand it is small timing differences. Add in low diffraction because a large baffle destroys time information while functioning as a mechanical averaging machine ( frequency response )