Posted by Wayne Parham [ 70.234.150.105 ] on October 08, 2007 at 02:07:26:

In Reply to: Re: Help with my car audio posted by gilipsie on October 04, 2007 at 14:34:12:

Well, in layman's terms, the formula that predicts the frequency a box is tuned for assumes a straight port, not one that is bent or flared or made into a "T" shape. Those kinds of changes are straightforward, and a finite element analysis could surely be done which would give a very accurate frequency prediction. But the Helmholtz formula assumes a straight port, so if you deviate from that too much, the formula will become inaccurate. When making an unusually shaped port, you can always estimate, make the port how long you think it should be and then measure it and modify as needed. Best to make it long at first, that way you can trim it down to size to get the desired frequency.

Replies: