a simple fix is what Canadian and UK forums have as effective forum screening tool : new member posts will be held in limbo before release into the audio forum, pending a review first by the moderator.
I have recommended this MANY TIMES! The single biggest problem is people posting for the immediate gratification of seeing their blather in print. Anyone with anything truly valuable to say knows it will be just as valuable in an hour as now.
The moderator complaint is this is too much work. But it doesn't have to be. This could be rolled out one topic at a time. Start with Misc Audio. Anyone wanting a serious discussion starts it in Misc Audio. All posts on Misc Audio are moderated. Nothing gets posted without first being reviewed and deemed ON TOPIC. Anyone trying to post off-topic gets a warning. Three warnings they get the boot.
Start with one Topic, see how it goes. What have we got to lose?