Posted February 17, 201312 yr Hi I recently had a box built by someone and I want to make sure the tuning is rightThe ports should be tuned to 33hz The box is for (2) digital designs 2500 12" It is a dual 12 box, sub + port firing foward34W X 14H X 24D outer dimensions 2 ports come together in the middle and are fully seperated til an inch from the frontthe 2 chambers are completely seperated down the middle an outer dimension: the port walls on both sides are 18 inches long into the box inner dimensionsthe port height 12.5port width: 1.75-2inches (starts at 1.75 at top, slanted to 2inches by the bottom) I hope this isnt too confusing I can try 2 take pics if needed but id have 2 figure all that outas ive never tried sending pics to my email from my phone If you have a calc screen shot or anything 2 prove that the tuning is wrong or anything is wrongim going 2 print out your response and take it to the guy for a full refundhe claims he used bass box pro which i know is legitIm just not hitting the lows like I should -thanks
February 17, 201312 yr You're not mentioning any internal length, does the port not turn and L in the back? Also, what was the intended internal volume? Why is the port slanted, wider at the bottom than it is at the top?
February 17, 201312 yr Just on the preliminary rundown I'm highly doubting anything about this enclosure was correctly calculated.
February 17, 201312 yr Author You're not mentioning any internal length, does the port not turn and L in the back? Also, what was the intended internal volume? Why is the port slanted, wider at the bottom than it is at the top? port wall is 18 inches long, no L 2.4 per side idk i mentioned that because it doesnt seem right 2 me, do you agree? pics coming soon
February 17, 201312 yr I'm getting only a hair over 2cuft NET volume per chamber with around 38hz tuning and WAY too little port area per sub. Sorry dude, it's looking like whoever you had build this for you had absolutely no idea what they were really doing.
February 17, 201312 yr How much did you pay for that? It does not appear to be very well built. Is the dividing board inside of the port slanted, and how thick is it?
February 17, 201312 yr That seperator doesn't go all the way back at all, that's a 4" x 12.5" x 18" port that I can guarantee will be tuned considerably higher than the upper 30's. Working on the exact numbers now.
February 17, 201312 yr Author the seperator down the middle divides the two chambersthere is 2 seperate ports i paid cost of materials but ill get that back if i can get some screenshotsof some calculators saying otherwise
February 17, 201312 yr Author How much did you pay for that? It does not appear to be very well built. Is the dividing board inside of the port slanted, and how thick is it? yes its slanted and half a inch thick, rounded
February 17, 201312 yr The separator goes all the way to the back wall? It sure as hell looks as though I can see it's shadow under it in that first picture. I guess it could be a reflection of the light in the resin though. If it is indeed fully seperated you're looking at 2.25cuft NET with 22sqin of port area tuned to ~37hz. If not then it's about 4.5cuft NET tuned to about 36hz (I was indeed thinking backwards on my original tuning thought if they weren't separated) so all in all by the numbers, the enclosure is a bit larger than it should be for the subs with WAY too little port area. The tuning itself isn't completely horrid, but definitely not 33hz. My guess is the guy who built this, aside from having raw enclosure construction skills, just didn't know how to properly calculate and design an enclosure. The enclosure being oversized is most likely why the subs don't seem to handle power worth a damn. Also, you have to remember that all these numbers are best educated guess/calculation. I've run the numbers as you've posted them to do the calculations, but without getting in there and really looking closely at all of it and measuring each and every panel accurately it's hard to be 100% certain on the numbers. Though I feel better than 90% certain on what I've figured.
February 17, 201312 yr Author The separator goes all the way to the back wall? It sure as hell looks as though I can see it's shadow under it in that first picture. I guess it could be a reflection of the light in the resin though. If it is indeed fully seperated you're looking at 2.25cuft NET with 22sqin of port area tuned to ~37hz. If not then it's about 4.5cuft NET tuned to about 36hz (I was indeed thinking backwards on my original tuning thought if they weren't separated) so all in all by the numbers, the enclosure is a bit larger than it should be for the subs with WAY too little port area. The tuning itself isn't completely horrid, but definitely not 33hz. My guess is the guy who built this, aside from having raw enclosure construction skills, just didn't know how to properly calculate and design an enclosure. The enclosure being oversized is most likely why the subs don't seem to handle power worth a damn. Also, you have to remember that all these numbers are best educated guess/calculation. I've run the numbers as you've posted them to do the calculations, but without getting in there and really looking closely at all of it and measuring each and every panel accurately it's hard to be 100% certain on the numbers. Though I feel better than 90% certain on what I've figured. How is the enclosure over sized if each chamber is 2.2 and that what the subs call for?how is the port size too small? what should it be?which box calculator progam do you use? I'm looking for someone with bass box pro to put in the measurements providedand screenshot/post the results so i can print it out and show the dude whats the bad thing about the port being slanted the way it is? port noise? I dont have much of an arguement 4 the guy as of yetI cant just go 2 him like it was poorly built
February 17, 201312 yr This looks to be a case of bad measurement. I put the exact measurements you gave with torres and it doesn't take in to account that the ports are separated. This would be with the same common port at 3.5 with a divider. If you were to remove the divider alone it would bring tuning up to 35.36hz, but currently I think you're close to around 36.08 - 37.48hz simply because of the port being all slanted.
February 17, 201312 yr The separator goes all the way to the back wall? It sure as hell looks as though I can see it's shadow under it in that first picture. I guess it could be a reflection of the light in the resin though. If it is indeed fully seperated you're looking at 2.25cuft NET with 22sqin of port area tuned to ~37hz. If not then it's about 4.5cuft NET tuned to about 36hz (I was indeed thinking backwards on my original tuning thought if they weren't separated) so all in all by the numbers, the enclosure is a bit larger than it should be for the subs with WAY too little port area. The tuning itself isn't completely horrid, but definitely not 33hz. My guess is the guy who built this, aside from having raw enclosure construction skills, just didn't know how to properly calculate and design an enclosure. The enclosure being oversized is most likely why the subs don't seem to handle power worth a damn. Also, you have to remember that all these numbers are best educated guess/calculation. I've run the numbers as you've posted them to do the calculations, but without getting in there and really looking closely at all of it and measuring each and every panel accurately it's hard to be 100% certain on the numbers. Though I feel better than 90% certain on what I've figured. How is the enclosure over sized if each chamber is 2.2 and that what the subs call for?how is the port size too small? what should it be?which box calculator progam do you use? I'm looking for someone with bass box pro to put in the measurements providedand screenshot/post the results so i can print it out and show the dude whats the bad thing about the port being slanted the way it is? port noise? I dont have much of an arguement 4 the guy as of yetI cant just go 2 him like it was poorly built I'm not completely convinced the DD's like larger enclosure, but that's beside the point, I was saying that because you said they didn't sound like they could take the power. That's generally indicative of a driver being in an enclosure that's too large. Port noise is the biggest issue with a port that's too small, I see the DD's needing 77sqin for both from stefan's port area calculator. It may not be super shy on port area, but it's still not all they should probably have. The slant reduces port area on one side and raises it on the other. It will affect port noise and tuning on each side. I'm no expert and have never made any claim to be. It still seems to me like this enclosure, poorly built and tuned or not, is wrong for the subs. I would expect the performance to be better than what you're describing.
February 19, 201312 yr Author just took the chamber divider out of the port, sanding it smoothwiring subs next
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