Cj Kumz Posted November 17, 2014 Report Share Posted November 17, 2014 Hey with those dimensions your gross volume is 1.58 cubes and after woofer displacement that lives you with 1.44 cubes. Do a 4 inch port that's 23 inches long that should give you a tuning of around 32 hz with 10 sq inches per cube.Not a real way to determine correct port area.I normally use 9-12 sq inches/cube for areos. I got my internal volume subtracted sub and port displacement, then divided that volume into the port area of the port. Where did I go wrong?? Vw Polo Pioneer Deh-6050UB Sundown Saz-3500d DD Audio 9500 15'' 5.5 cubic feet box with 10 inch port @ 38hz I live to hear the Bass drop!!! Link to comment Share on other sites More sharing options...
Krakin Posted November 17, 2014 Report Share Posted November 17, 2014 The volume of a box has absolutely no correlation to the amount of area is needed for a vented enclosure, being: vented, 4th order bandpass, 6th order bandpass or even the intricate 8th order bandpass, along with anything that deals with a passage way for air moving from point a to point b. The frequency at which the passage way is tuned, the x-max of the speaker, and the amount of radiating area determine the amount of area needed. The area determined from the equation using said variables is optimal for a circular port with no bends. the more inefficient the port becomes the more area you will need in order achieve the same port results. 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. Link to comment Share on other sites More sharing options...
Cj Kumz Posted November 17, 2014 Report Share Posted November 17, 2014 The volume of a box has absolutely no correlation to the amount of area is needed for a vented enclosure, being: vented, 4th order bandpass, 6th order bandpass or even the intricate 8th order bandpass, along with anything that deals with a passage way for air moving from point a to point b. The frequency at which the passage way is tuned, the x-max of the speaker, and the amount of radiating area determine the amount of area needed. The area determined from the equation using said variables is optimal for a circular port with no bends. the more inefficient the port becomes the more area you will need in order achieve the same port results. Thanks alot for that clarification. So what do you suggest is the best way to help out the OP Vw Polo Pioneer Deh-6050UB Sundown Saz-3500d DD Audio 9500 15'' 5.5 cubic feet box with 10 inch port @ 38hz I live to hear the Bass drop!!! Link to comment Share on other sites More sharing options...
Krakin Posted November 17, 2014 Report Share Posted November 17, 2014 The volume of a box has absolutely no correlation to the amount of area is needed for a vented enclosure, being: vented, 4th order bandpass, 6th order bandpass or even the intricate 8th order bandpass, along with anything that deals with a passage way for air moving from point a to point b. The frequency at which the passage way is tuned, the x-max of the speaker, and the amount of radiating area determine the amount of area needed. The area determined from the equation using said variables is optimal for a circular port with no bends. the more inefficient the port becomes the more area you will need in order achieve the same port results. Thanks alot for that clarification. So what do you suggest is the best way to help out the OP The very first reply to the thread. 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. Link to comment Share on other sites More sharing options...
mylesshivers Posted November 17, 2014 Author Report Share Posted November 17, 2014 The volume of a box has absolutely no correlation to the amount of area is needed for a vented enclosure, being: vented, 4th order bandpass, 6th order bandpass or even the intricate 8th order bandpass, along with anything that deals with a passage way for air moving from point a to point b. The frequency at which the passage way is tuned, the x-max of the speaker, and the amount of radiating area determine the amount of area needed. The area determined from the equation using said variables is optimal for a circular port with no bends. the more inefficient the port becomes the more area you will need in order achieve the same port results. Thanks alot for that clarification. So what do you suggest is the best way to help out the OP The very first reply to the thread. OK, so slotted or aero? Cj I don't know if you read it, but the dimensions I gave were the internal dimensions(for clarification). I am still confused on what the best possible port design is.. Link to comment Share on other sites More sharing options...
Krakin Posted November 17, 2014 Report Share Posted November 17, 2014 A circular port will be the most efficient, but this doesn't mean you can just make it have less port area than a rectangular port. This mean the rectangular port will have to have more area to compensate for the loss of efficiency due to having more surface area along the port contacting the air. Either design works if given the proper area, however in a car areports are generally better because of using up less airspace. The only time I would suggest going with a slot port is when you don't have enough baffle area. 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. Link to comment Share on other sites More sharing options...
Joe X Posted November 17, 2014 Report Share Posted November 17, 2014 OP post vehicle you are doing this on and maximum external dimensions for a box and goals, best way to get better feedback. Now just to as some general information flared round ports handle better higher airspeeds which are closely related to losses, slot ports can work basically just as well in most applications as long as you keep airspeed low enough by increasing port area, sadly that results in a larger box, if you can't fit a slot ported box you can try round ports. Many enclosures using round ports will result in insufficient port area to fit the port or ports to the tuning you want and very frequently odd shaped boxes that result in dysfunctional use of space of your trunk. Most problems with round ports are due the limited sizes they come. I really believe that there are many round port based enclosures working worse than a proper slot ported version due to the issues mentioned. So which to use? to me it depends entirely on your application (and that includes you want to use round ports just because) one of the big advantages of round ports is that you can change tuning easy, burp crowd appreciate this very much and so you see this round ports used very frequently in that kind of application. Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted November 18, 2014 Report Share Posted November 18, 2014 ...flared round ports handle better higher airspeeds which are closely related to losses, slot ports can work basically just as well in most applications as long as you keep airspeed low enough by increasing port area... ...I really believe that there are many round port based enclosures working worse than a proper slot ported version due to the issues mentioned.... True dat! "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: Link to comment Share on other sites More sharing options...
philrab Posted November 18, 2014 Report Share Posted November 18, 2014 I'll just throw in what I did with my SA12. Bare in mind, I'm a bit under power vs. the OP throwing 1000 watts up it's behind. If I were running that power, I wouldn't have gone quite so big on my net airspace, but I digress. 2.15 cubic feet net 3" x 8" rectangle port, hit both ends with 1/4" roundover bit for a little bit of a flare, 24 square inches of port, tuned to 33hz. I had a really long enclosure to fill the whole back of my hatch minus what I needed for port clearance, so that port is all in a straight line. I prefer that as I tend to think it's more efficient vs. having a bend in it. Also, used a flush trim bit in my router and sanded to make sure there were no seams to much up the air flow in the port and cause additional turbulence. Works great, very authoritative from 40 hz on down, will play up to about 60hz without breaking a sweat, zero port noise. 2015 Toyota Tacoma Build Thread 2007 Mazda 3; 5000K HID's, Kenwood Excelon KDC-X997, Infinity Reference 6.5 comps in front and coaxials in the rear doors, JL 320.4 four channel, Rab Designs built ported enclosure with an SA12, Kenwood monoblock, Redline Leater shift boot/e-brake boot/center console cover, JBR short shifter/shifter bushings/rear motor mount. Build Thread 1996 Mazda Miata: Kenwood Excelon HU, Alpine speaker in the doors, Clearwater (miata specific) headrest speakers. 1994 Mazda Protege: Kenwood Excelon HU, Infinity Reference 2 ways all around, 2x RF Punch 10's in ported boxes. Link to comment Share on other sites More sharing options...
mylesshivers Posted November 18, 2014 Author Report Share Posted November 18, 2014 OK, y'all are very, very informative, I am actually starting to get overwhelmed. Let me know if this is correct, Since I am overpowering the subwoofer there needs to be more port area because of more airspeed. Slot ports require larger box's. My set max dimensions are L = 30" H = 14". The width is flexible up to 13" My "application" and goals is for a daily driver, I listen to country all the time, but love the bass. I would like the box to be thin enough to be able to put golf clubs on my trunk without having to worry. I also have a question, do I need to power it at 600 rms to be able to correctly and effectively determine to port area? Link to comment Share on other sites More sharing options...
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