Texas Tech Posted January 29, 2008 Report Share Posted January 29, 2008 (edited) Question: In the first picture the length of the port would be 17 in. long assuming the distance from the end of the port to the back wall of the enclosure is longer than the width of the port. If this is wrong please tell me. However what if you wanted to add a double baffle, but the top baffle is only a trim panel, so the subs are Not screwed into this top baffle. Would you determine the length of the port like i show in this post? the first picture is just a regular box, with NO double baffle. The port length is 17 in. This second picture shows a double baffle, but like stated before, the top baffle is only a trim panel? Would the length now be 17.75 in. long?I am guessing yes however I havent asked anyone so. Edited January 30, 2008 by Texas Tech Quote Baylor University Accounting Link to comment Share on other sites More sharing options...
joey2714 Posted January 29, 2008 Report Share Posted January 29, 2008 it would be 17.75 yes.. Quote play Moola.com its actually fun and free... click here to join Money games! its just games with free money! Link to comment Share on other sites More sharing options...
andym85 Posted January 29, 2008 Report Share Posted January 29, 2008 i would also add half of the ports width to the total length for end correction, since that port uses part of the box as a port wall... Quote i likes me some audio stuff... Link to comment Share on other sites More sharing options...
Texas Tech Posted January 29, 2008 Author Report Share Posted January 29, 2008 even though i stated "assuming the distance from the end of the port to the back wall of the enclosure is longer than the width of the port?" you would still add half the ports width, i would think you wouldnt Quote Baylor University Accounting Link to comment Share on other sites More sharing options...
Torres Posted January 29, 2008 Report Share Posted January 29, 2008 if you have a wall of the enclosure to help act as a side of the port, the subs will still 'think' that the port is longer since it's using one of the walls. that's what the speaker 'sees' Quote Link to comment Share on other sites More sharing options...
andym85 Posted January 29, 2008 Report Share Posted January 29, 2008 if you have a wall of the enclosure to help act as a side of the port, the subs will still 'think' that the port is longer since it's using one of the walls. that's what the speaker 'sees' x2.... http://mobile.jlaudio.com/support_pages.php?page_id=165 Quote i likes me some audio stuff... Link to comment Share on other sites More sharing options...
Texas Tech Posted January 30, 2008 Author Report Share Posted January 30, 2008 (edited) So even though the length from the end of the port (physically) to the back wall of the enclosure is longer than the width of the port, it still doesnt matter, you add half the ports width for end correction. I made this diagram, tell me if I am correct. The length of the port you would use for tuning would be 19 in. And the length you would use for tuning here would also be 19 in. I know this is not practical but in theory it should be upheld from what you said. Edited January 30, 2008 by Texas Tech Quote Baylor University Accounting Link to comment Share on other sites More sharing options...
andym85 Posted January 30, 2008 Report Share Posted January 30, 2008 ^^^from what i know and how i do it, that is correct Quote i likes me some audio stuff... Link to comment Share on other sites More sharing options...
Texas Tech Posted January 30, 2008 Author Report Share Posted January 30, 2008 (edited) Referring to this: "The effective length of the port is found by adding an end correction factor. An end correction factor is necesary because more often than not, one wall of the port is also one wall of the enclosure and this wall extends beyond the end of the port thus effectively adding length to the port (remember, the driver can't "see" the length of the port, it can only go by what it "feels" is going on). " -JL Audio Website Yes, however the wall of the enclosure is not a wall of the port. If it were a wall of the port, then the ports width changes, at the beggining of the port (the baffle) the width is 4 inches, and then at the end of the width is 8 in. or 20 in. (depending on which diagram you are looking at). However it would be more appropriate if it were like this, in this case you would have to add half the ports width: Here the physical length is 18.75 in. and the length for tuning freq. formula would be 20.25 in. In that diagram the enclosure wall extends the port, the port maintains the same width throughout the entire port. I hope i am not coming off as disrespectful or rude. Edited January 30, 2008 by Texas Tech Quote Baylor University Accounting Link to comment Share on other sites More sharing options...
andym85 Posted January 30, 2008 Report Share Posted January 30, 2008 no, ur not coming of disrespectful or rude at all... i see what ur saying though and it does make sense...ports down the middle have always been a tad fuzzy to me because of the whole end correction thing... but what ur saying makes total sense...plus, an inch or so shouldnt change ur tuing to drastically, so i would go off of what ur saying...im gonna have to really sit down and think about it more later... Quote i likes me some audio stuff... Link to comment Share on other sites More sharing options...
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