I have full-text access to the world’s major (and minor) newspapers, in a few cases going back to the late 1700s. Recently, I was doing some broad searches on the Times of London, and some stories from the 1850s/1860s really caught my attention. In two particular cases it appears that descriptions of odd/unusual/unexplained sounds are worth pursuing. There were no “engines idling” outside people’s homes at that time, but there was large industry, which itself was pinpointed as the source of some complaints.
If you know how to use academic search engines and are interested in access to these newspaper archives and doing the digging on this, then contact me.