Originally Posted by surreal
Groundpound. STOP DROP AND GTFO. Rule of thumbs dont apply and ARE NOT accurate. Ever! There is no educated guesses for 4th orders. Simple as that.
Model is out, see what comes up. Use a 4th calc and whatever ripple value you want. Get some idea and come back with more specific questions.
Truth. I've used all the rules of thumb and "suggested" specs and have had them fail more often than not. I've built exactly to modeling software specs and had it fail. I've built the exact box that someone else had success with and had it fail.
The thing with BP's is, you have to be prepared to fail and modify or rebuild. You are most likely NOT to get it perfect the first or even the 7th time. Those guys who do those big ass BP walls have big brass ones, because if that shit fails, they're out a whole lot more than a sheet of wood or two.
They're so funny because you can't just change the port out and change the whole attitude of the box like you can with a standard ported. You really have to play with chamber volumes. The port length has very little to do with the response.
When they are done right though... they are beastly. My latest was a 4th order for (4) SA8's in my trunk ported through the armrest. 147'[email protected]
34hz on 2k. Tasty.