Cj Kumz Posted January 20, 2014 Report Posted January 20, 2014 Hey guys. Quick question. Okey we all know that a slotted port needs 12-16sq inches/cube and 8-12sq inches/cube for aero ports right. Now my question is what are the advantages and disadvantages of using the upper limit vs the lower limit?? 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!!!
Krakin Posted January 20, 2014 Report Posted January 20, 2014 None of that is true for port area per foot, you need X amount of port area for your driver no matter how much airspace it has. There are some formulas that can get you close to what you need, but only testing different boxes will get it perfect. Here are some to check out. http://www.carstereo.com/help/Articles.cfm?id=21 http://www.diysubwoofers.org/misc/portcal.htm For your question if you don't have enough port area you will experience port noise, less power handling, harmonic distortion, and other negative affects towards your experience. 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.
Cj Kumz Posted January 21, 2014 Author Report Posted January 21, 2014 Okey I get. Ama look at those links thanks.. So from your experience is more port area better as long as you stay in the range?? 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!!!
Krakin Posted January 21, 2014 Report Posted January 21, 2014 The range you stated in the first post doesn't matter. Every driver needs a different amount of port area than another, and a generalization doesn't cut it. 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.
Raptorman Posted January 21, 2014 Report Posted January 21, 2014 I +1 what Krakin says. The general 12-16 rule is a decent start for beginners.... But X amount of port for this certain woofer is the method I like best. My wall had optimum port for the woofers and it only came out to 10 sqin per cube.To answer your question, though, typically the more port a woofer has, the peakier it may be, but louder; the smaller the port, less of a peak, more of a flatter response and more extended response, but less output. Very general statement though, take it with a grain of salt. 1996 GMC Sonoma Four Fi BTL Neo 18's In 2:1 6th Order Bandpass 2 Ampere 5k's @ .5 TEAM FI TEAM #LITHIUMCANTDEMO On 10/20/2013 at 0:37 AM, KillaCam said: Fucking with a Prius driver is like making fun of a disabled kid. Pussies.
Smoove Posted January 21, 2014 Report Posted January 21, 2014 So let me throw a monkey wrench into some of this. Because I am doing a blowthrough I am limited on space. Based on the amount of Xmax and other T/S numbers I cant do the so called perfect amount of port. So I have to use the 12-16sqin per cube rule. And there are lots of formula's, but we aren't building boxes for a square living room. Sometimes building several test boxes is your best option. 2 Team Fi 15's v1 2 DD M5's 970amps of Alt 6th order blowthroughThe truck Blowthrough build : http://www.stevemeadedesigns.com/board/topic/155555-smooves-1996-chevy-ext-cab-c1500-slow-build/The 350z build : http://www.stevemeadedesigns.com/board/topic/170694-smooves-2003-nissan-350z/ My FB page https://www.facebook.com/pages/Smooves-Car-Audio-and-performance/719746144805343 Team Fi Audio http://www.ficaraudio.com/
Krakin Posted January 21, 2014 Report Posted January 21, 2014 If you get an extended bass shelf with lower port area it will be very unpleasant to listen to as you will have chuffing like crazy. With proper port configuration you will get 200 times less output per octave below tuning. If you want the lows you should get a driver that will support them and then design your box accordingly. My opinion for the people that complain about not having the room to fit the amount of port that the driver(s) need is that there are sacrifices that have to be made in every build, I personally would sacrifice cone area for a proper port and box, instead of shoving 10 pounds of crap in a 5 pound bag. 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 21, 2014 Report Posted January 21, 2014 Also let's not forget flaring and mainly the area ratio; area ratio gives an indication of how quickly the air has to change velocity as it exits a flared port, and is a more useful measure than flare radius alone. 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.
Cj Kumz Posted January 21, 2014 Author Report Posted January 21, 2014 Thanks alot guys. Will be building a box soon for my SPL Dynamics sub.(http://www.spldynamics.fi/products/subwoofers/SPL-series/spl-380d1a-e.html). And want maximum output. 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!!!
Cj Kumz Posted January 21, 2014 Author Report Posted January 21, 2014 Thanks alot guys. Will be building a box soon for my SPL Dynamics sub.(http://www.spldynamics.fi/products/subwoofers/SPL-series/spl-380d1a-e.html). And want maximum output. I wanna go loud but still maintain the deep bass. 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!!!
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