Fi_all_d_way Posted January 23, 2008 Report Share Posted January 23, 2008 hey guys when you have make a port 30inchs long to get 35hz ...how do you measure that?? look at the pic i posted....do you measure the blue line or the green line??? http://img402.imageshack.us/my.php?image=77509614qu3.jpg Link to comment Share on other sites More sharing options...
andym85 Posted January 23, 2008 Report Share Posted January 23, 2008 blue line + half of the ports width for what they call "end correction" i likes me some audio stuff... Link to comment Share on other sites More sharing options...
Fi_all_d_way Posted January 23, 2008 Author Report Share Posted January 23, 2008 blue line + half of the ports width for what they call "end correction" thanks alot bro for your quick response Link to comment Share on other sites More sharing options...
Fi_all_d_way Posted February 18, 2008 Author Report Share Posted February 18, 2008 thanks alot bro for your quick response bro a guy told me i need to minus not plus....can you tell me what is correct ...thanks bro Link to comment Share on other sites More sharing options...
andym85 Posted February 18, 2008 Report Share Posted February 18, 2008 here is where i learned about end correction http://mobile.jlaudio.com/support_pages.php?page_id=165 think about it logically for a second.....if you have a slot port that uses part of a box wall as a port wall then wouldnt you think it would be longer, in theory?... as quoted from that link "(remember, the driver can't "see" the length of the port, it can only go by what it "feels" is going on). "....so by using a box wall as a port wall, you are effectively lengthing the port by half of the ports width, not reducing it...im not sure what they other guy is thinking...? i likes me some audio stuff... Link to comment Share on other sites More sharing options...
IH8PunkRok Posted February 18, 2008 Report Share Posted February 18, 2008 amatt is an expert on boxes trust him bro hes right -Matt2005 Dodge Magnum RTJVC KD-AVX1 2 PPI S580.2 Obsidian Audio ST1 Horn Tweeters PRV 8MB450s Audio Legion 3500.1D 2 RE MT 18s 360 ah LiFePO4 BatterySHCA 2/0 155.2 @ 29 hzKicker CVR 15's buildDD 3512e buildMini T-Line Build(6) 8s BuildNightshade 15s Wall BuildMagnum AB XFL 12s BuildNewest Magnum Build Link to comment Share on other sites More sharing options...
andym85 Posted February 18, 2008 Report Share Posted February 18, 2008 amatt is an expert on boxes trust him bro hes right lol....im FAR from an 'expert', but im pretty damn sure im right on this one... i likes me some audio stuff... Link to comment Share on other sites More sharing options...
Decaf Posted February 19, 2008 Report Share Posted February 19, 2008 bro a guy told me i need to minus not plus....can you tell me what is correct ...thanks bro if ur refering to me thats not what i said: 1) when u use one of the sides of the enclosure the sub "sees" or "thinks" the port is longer since one side extends beyond the other port wall. this lowers ur tune frequency slightly. so if it says 3wide x 25l, the actual length the sub sees is around 26.5, so you dont need to add onto the 25, you just need to understand that the end correction with a slot port slightly lowers the tune freq. if you want 35hz, and it says on bassbox to make it 25, then you could theoretically make ur port 23.5 and it would be tuned to 35hz actually, instead of the length [from bassbox] of 25 which [would yeild a port length of 26.5]might yield 1-1.5 hz lower tuning so as i said, i wasnt telling you to change the physical length of the inner port wall or the total port length, i said that when using a slot port the effective length of the port is longer than what most "box programs" will measure because of the end correction factor. thus if you are trying to squeeze every cuft out of an enclsoure, you could shorten the total port length by the length of the end correction factor and it would yeild the bassbox's tuning, because bassbox (i think) assumes that 30" means 30", not 30" + an end correction and im far from an expert, and im not as good with boxes as amatt, but i understand ecf i.e. when i make my slot ported boxes and lets say one needs to be tuned to 32hz, i will build it to 33hz knowing it is actually tuned lower Link to comment Share on other sites More sharing options...
andym85 Posted February 19, 2008 Report Share Posted February 19, 2008 ^^^ couldnt have said it better myself! i likes me some audio stuff... Link to comment Share on other sites More sharing options...
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