I believe a little differently than some here... and if you have been a member for quite some time, you might remember our little "difference of opinion"...

OK, here's the deal. We are developing sites for the user, and as such, they
must remain the focus of our development. I see it like this, if they aren't posting, it's because I am not making the site interesting enough for them to want to post. It's that simple.
I don't advocate deleting user records because they are one of your most valuable marketing tools. Don't send them an email saying: "We noticed you haven't been around, so we are gonna cut off your acct in case you might wanna come back to post if we ever make something interesting enough to post about". Instead build in
quality content, something you and your members would be interested in,
then email them every 3-6 weeks or so telling them what's going on, what's the latest discussion about, what's new in your topic for a forum (audio/video equipment in your case Jeff), etc etc etc...
They thought enough about your content to sign up and give you their email address, make it count... it doesn't matter if your member count is 11 or 11,000, give them a reason to come back, remind them that you are still there and have the latest info regarding what they are interested in. It is
much more difficult to get new members than to keep present ones...
basic marketing 101.