When Concordes supersonic audiability was being checked by Capt John Hutchinson in Port Dickson Malaysia due to complaints that it was rattling windows and waking people up there while still supersonic over the Straits of Malacca en route into Singapore the verdict was that the sonic boom, having gone directly downwards from the aircraft then spread up to 20 miles each side. The noise depended on atmospheric conditions but in an area familiar with tropical thunderstorms even the worst booms were hardly shattering,- more a dull thud than a crack. The loudest complainer,- almost the only complainer,- was an elderly Brit. By edging slighly further out into the Straits to avoid Port Dickson the only known recipients of the boom were the staff of a lighthouse in Indonesia, and they didnt seem fussed at all.