There aren't many good acoustic engineering programs out there. I've looked.
EE is very related to audio (don't know why someone said it wasn't). The cornerstone of audio is electricity and electronics; even the mechano-acoustical aspect of audio is often simulated with analog electrical circuits. Also, signal processing is an important part of the present and future of audio and that's right out of your EE classes.
Mechanical engineering has some value, although not to the extent that EE does.
Don't go to any of the installer institutes. There is nothing worth the tuition cost at any of those places. If you want something similar with more value, shell out some money and get a class from experts actively involved in the field: Mark Eldridge has held a few lately with very positive feedback.
The best thing you can do is to pick classes that will make sense, rather than getting a specific degree. That means you'll take a lot of Physics classes, a number of general engineering classes, some computer science, some EE, and take some trades courses, too. Though you won't come out of it with a degree, it is probably the best way to specialize in the field.
There are lots of
books that you can read, and forums can be a good source for knowledge at the novice level. It is key that you pay attention to only those who have valuable insight; the same reliable posters can be found on mostly the same forums, since they're all passionate about the subject....but on CA.com, it just takes a bit more filtering to find those posts. If you're not already, you should be a member at
DIYMA and then supplement your discussion there by sharing what you've learned here, or getting involved in debate. You'll find the concepts are much easier to understand once you've learned them, then re-taught them several times over.