Jspawn80 Posted September 8, 2016 Report Share Posted September 8, 2016 So i made a ported box for my nissan titan with 4 sundown sa8 v3 and got ahead of myself. I got it carpeted,leather wrapped ect. I went to test bump it and got alot of port noise. I hadnt plugged the box into any software to see what the box would do before i built it and after i played it i plugged all my box specs into winisd and my port vent mach was .21 with a port that was 4 inches in diameter by 10 inches long which ive read it super high. Also my box is on the small side its all one common chamber and after subwoofer displacement but before port displacement im at 1.9 ft ^3 for all 4 subs. I already plugged up the previous hole i made and now im tying to figure out a way to port this box without port noise. Does anyone have any suggestions on what i could do? Ive spent too much on this box to just scrap it Link to comment Share on other sites More sharing options...
DLHgn Posted September 8, 2016 Report Share Posted September 8, 2016 Get a wider port. Unfortunately, if you do that, you port will need to be longer to have the same tuning as before. If you look at the graph on WinIsd that is labeled Rear Port Velocity (I believe) you should keep the velocity below 30 m/s and even lower than that if you can. I think my box gets up to like 26 - 28 m/s and I can start to hear the port noise. Link to comment Share on other sites More sharing options...
Mustang2dakota Posted September 8, 2016 Report Share Posted September 8, 2016 DLhgn is correct you'll need a wider port. Someone correct me if I'm wrong but a 4in aero port leaves you with about 12.56 sq inches of port cross-sectional area and a 1.9 cubic foot box requires approximately 19-23 sq inches off cross-sectional area. Having the correct amount of cross-sectional are should help decrease port noise. If it's possible maybe try adding another 4in port. 2014 JKU Sound: pioneer xav-65 4 12in pioneer tsw3003d4 2 pioneer gm-d9601 (much more in route) General: 18in worx rims 33in tire stinger src bumpers light bars 6k hids 2in leveling kit 3.25in lift The Build Log: http://www.stevemeadedesigns.com/board/topic/195839-2014-jku-build-4-12s/ Link to comment Share on other sites More sharing options...
ChevyBoy95 Posted September 8, 2016 Report Share Posted September 8, 2016 DLhgn is correct you'll need a wider port. Someone correct me if I'm wrong but a 4in aero port leaves you with about 12.56 sq inches of port cross-sectional area and a 1.9 cubic foot box requires approximately 19-23 sq inches off cross-sectional area. Having the correct amount of cross-sectional are should help decrease port noise. If it's possible maybe try adding another 4in port. Pretty much, if it was me I would add another of the same size 4" port (at the same length) and check the results. If it sucks, you will most likely either have a poorly sounding box or rebuild it correctly. Best Score to Date : 160.5 dB Outlaw (47Hz)[4 XM 15's & 2 Taramps Bass 12k's] BL : http://www.stevemeadedesigns.com/board/topic/147800-chevyboy95s-4-15s-7krms-wall-1533-db-on-half-power/YouTube: http://www.youtube.com/hitemwiththeflex/ Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted September 8, 2016 Report Share Posted September 8, 2016 Another 4" port may be enough port area, though it depends on how much power you are running. If you add another 4" port they will both need to be twice as long (approximately) to keep tuning the same. "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...
Mustang2dakota Posted September 8, 2016 Report Share Posted September 8, 2016 Another 4" port may be enough port area, though it depends on how much power you are running. If you add another 4" port they will both need to be twice as long (approximately) to keep tuning the same. This is slightly off topic, but I've been curious as to how power affects cross-sectional area. If you don't mind explaining it to me it would be much appreciated. 2014 JKU Sound: pioneer xav-65 4 12in pioneer tsw3003d4 2 pioneer gm-d9601 (much more in route) General: 18in worx rims 33in tire stinger src bumpers light bars 6k hids 2in leveling kit 3.25in lift The Build Log: http://www.stevemeadedesigns.com/board/topic/195839-2014-jku-build-4-12s/ Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted September 8, 2016 Report Share Posted September 8, 2016 This is slightly off topic, but I've been curious as to how power affects cross-sectional area. If you don't mind explaining it to me it would be much appreciated. The more input power you have, the higher your port velocity will be and thus the more port area you need to keep port velocity below the point where it negatively affects output. This is one of the problems with "port area per cube" rules, they don't account for how much power will be used. A 200 watt system needs a lot less port area than a 2,000 watt system does, even if the box size and tuning is the same. "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...
ckeeler11 Posted September 8, 2016 Report Share Posted September 8, 2016 Dont forget if you add more ports you will also be decreasing the volume of the box and in return raising the tuning. If it was me i would either run sealed or build another box. Triticum can explain better but the more power the more excursion, which translates to more air pressure. more pressure the bigger the hole needs to be to fit all the pressure. LOL very basic interpretation. Link to comment Share on other sites More sharing options...
jk13 Posted September 8, 2016 Report Share Posted September 8, 2016 I already plugged up the previous hole i made How does it sound now that it's sealed? Don't forget that your ports can run outside the box if needed. Provided you can make it work physically and aesthetically, that is. Static drops are my bag. Link to comment Share on other sites More sharing options...
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