I’m not interested in the sky trumpet phenomenon, and in fact the more I learn about it the more skeptical I become (e.g. https://www.youtube.com/watch?v=YVScTxRBHFY) but I have raw data for you on the topic. You see, the World Hum Map attracts not only Hum hearers, but others who are looking for answers to questions about variety of unexplained noises. The raw database contains a significant number of references to “trumpet”-type noises, and obviously I have ignored them for the purposes of the Hum Map. Note that the raw database contains spam, coarse language, and so on.
Here is a recent copy of the live database: