There have been a few seriously useful Acoustics Fora over the years. In two in particular I have gotten to know many Acoustician friends around the world. I have also learned a helluva lot from some of the greats, but also from humble discussions.
These two Fora have been rescued and Archived by unknown heroes IMO.
Thank you, thank you.
Let's hear it for the legendary, StudioTips https://web.archive.org/web/20060109211308/http://forum.studiotips.com/index.php
The antipodean JohnLSayers forum.
https://www.johnlsayersarchive.com/viewforum.php?f=2&sid=0537c48d16f3c58ac858ab633f5ea38d
John's site is also available on the archive.org as well as the archive site setup by
Sam Napolitano