khinds94 Posted January 16, 2015 Report Posted January 16, 2015 You determine it by cone area, xmax and tuning frequency. This is a good quick calculator. http://www.carstereo.com/help/Articles.cfm?id=31 I see, why does it give a minimum of 7.5" aero for a 12" driver with a 35mm xmax Because of the amount of air being moved. The port per cube rule came along when speakers had a much much lower Xmax. Xmax doesnt change the calculation much... How many people have you seen run 50 sq inches of port on a single 12" driver? the calculator doesnt seem right to me 03 Sable LS AA mayhem 12" D2 Sundown ZV4 12" D1 Tantric HD 12" D2 Tantric SHD 12" D1 Sundown X12 V2 D2 2.5 cu net Sundown 2000d @ 1 ohm XS Power XP2000 Sky High Sound Deadener Sky High wire Stock alt
Krakin Posted January 16, 2015 Report Posted January 16, 2015 It doesn't mean you will get better SPL, it will eliminate chaffing and vastly improve your sound reproduction quality. If your building a box to listen to, not solely for the lanes then follow the calculator, if you are for the lanes only then you should already know you need to try multiple variations for the highest acoustical output. Krakin's Home Dipole Project http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370 Krakin, are you some sort of mad scientist? I would have replied earlier, but I was measuring the output of my amp with a yardstick . . . What you hear is not the air pressure variation in itself but what has drawn your attention in the two streams of superimposed air pressure variations at your eardrums An acoustic event has dimensions of Time, Tone, Loudness and Space Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears, thus no formula can achieve a definite effect for every listener.
Krakin Posted January 16, 2015 Report Posted January 16, 2015 It's science and proven fact, you use the same fundamental calculations when building engines or instruments or aerospace equipment. The calculator is designed specifically for audio and follows the same equations laid out by the man who even today we use his parameters to determine the properties of speakers. Krakin's Home Dipole Project http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370 Krakin, are you some sort of mad scientist? I would have replied earlier, but I was measuring the output of my amp with a yardstick . . . What you hear is not the air pressure variation in itself but what has drawn your attention in the two streams of superimposed air pressure variations at your eardrums An acoustic event has dimensions of Time, Tone, Loudness and Space Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears, thus no formula can achieve a definite effect for every listener.
khinds94 Posted January 16, 2015 Report Posted January 16, 2015 It doesn't mean you will get better SPL, it will eliminate chaffing and vastly improve your sound reproduction quality. If your building a box to listen to, not solely for the lanes then follow the calculator, if you are for the lanes only then you should already know you need to try multiple variations for the highest acoustical output. Why are you defending the calculator? if you have ever tweaked with a box before you would know that those numbers it gives are completely wrong for any daily application. 03 Sable LS AA mayhem 12" D2 Sundown ZV4 12" D1 Tantric HD 12" D2 Tantric SHD 12" D1 Sundown X12 V2 D2 2.5 cu net Sundown 2000d @ 1 ohm XS Power XP2000 Sky High Sound Deadener Sky High wire Stock alt
Triticum Agricolam Posted January 16, 2015 Report Posted January 16, 2015 The best method I've found for determining port area is to plug all the info you have into something like WinISD or TermPro and see what port velocity you get for the power you are running. The port calculator listed above or the port per cube method both operate based on some assumptions. This doesn't make them good or bad, they are just starting points and are limited in there usefulness. Also I'd like to squash a misconception I saw earlier in theis thread. Port size should have no effect on the peakyness or flatness of the box. Box size and tuning does. The only time port size is going to effect it is if the ports are grossly undersized and are killing output around tuning. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds:
betweenmatt Posted January 16, 2015 Author Report Posted January 16, 2015 wow this thread got pretty hot lol.... So I'm running 4 10" alpine type e's, which have a 10mm xmax. According to the calculator I need 8" diameter port with just under 17" of length for one port. My box will be 5.5 cubes with the port mostly internal. I'm tuning to 32 hertz. Is this a solid plan? edit: and according to winisd with 5.5 cubes and 8 inch diameter i need 17.72 inches long. Is that more accurate than the website calculator?
CleanSierra Posted January 16, 2015 Report Posted January 16, 2015 You determine it by cone area, xmax and tuning frequency. This is a good quick calculator. http://www.carstereo.com/help/Articles.cfm?id=31 I see, why does it give a minimum of 7.5" aero for a 12" driver with a 35mm xmaxBecause of the amount of air being moved. The port per cube rule came along when speakers had a much much lower Xmax. Xmax doesnt change the calculation much... How many people have you seen run 50 sq inches of port on a single 12" driver? the calculator doesnt seem right to me Me, I do. When you have a sub with a throw of 34MM xmax, you NEED port to make it function as intended. Port per cube theory need to burn a fiery death, like now. Im not the one you want to try to troll. Just a fyi for you.
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