I also wonder when those who mention it when writing reminiscences get confused with other event. A woman in Benton, AR wrote of hearing the cannons at the battle of Helena, AR July 4, 1863 and worrying because her husband was there. Distance about 140 miles. Nothing to funnel sound as sound waves would have to cross miles of flat Miss River and Ark River delta. I think she remembered a little,too much in her writing. But acoustic shadows as well as the opposite do occur and did.