3.0 cubic feet sealed
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Silver Member Username: CenusHicksville, Ohio Usa Post Number: 322 Registered: Jan-05 | i have finally decided on 3.0 cubic feet sealed for my atlas but i can't get the dimensions right, every time i calculate the size of the box its always too big or too small. so can any1 help me out and just give me the dimensions. or mabey im just calculating it wrong cause this car audio book i have says to times the length/height/width then divide by 1728. is that the correct way? |
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Gold Member Username: GlasswolfWisteria, Lane USA Post Number: 8686 Registered: Dec-03 | an atlas what? 18"? 3cu ft is good for a sealed 18" sub if it's a fifteen, you'd be fine with 2.5cu ft after driver displacement. LxWxH for colume, + driver disp. |
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Bronze Member Username: LegacyaudioPost Number: 82 Registered: Feb-05 | well considering a cu foot = 1728in then yes once u find the volume of your box to convert it to cu ft u would divide by that not a very hard concept-- read the manual to your subs and it should tell u the dinesions |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 282 Registered: May-05 | normally when I make boxes, I pick out the critical dimensions first. I'll set any dimensions I can first, and then leave maybe 1 axis to determine using a simple l*w*h forumla. The key is, if you want a 3' cubed box, when you multiply all inside dimensions (in inches), you should get 5184. Most of the boxes I build have atleast one angle so its a little bit more difficult but its all really 8th grade geometry, nothing complicated. |
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Silver Member Username: CenusHicksville, Ohio Usa Post Number: 323 Registered: Jan-05 | ya its a 15, and i haven't taken geometry yet, thats next year, i have heared that you should make the box be a rectangle not a square because it causes cancallation is this true? |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 296 Registered: May-05 | true, it is best to avoid a perfect cube, although standing waves really can't be generated in a relatively small box with a sub thats crossed over at ~100Hz. 3 cubic feet is pretty big though, just don't make it abnormally deep. angling the front or back would also be a good idea, but may require a class in geometry, but idk. |
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Silver Member Username: CenusHicksville, Ohio Usa Post Number: 325 Registered: Jan-05 | ya my school is weired they make you take algebra 1 before geometry, also how much space will the sub take up, i think its called sub displacement, i was thinking .2 or .3 cf. and what if the sides of the box was angled, would this help take out the standing waves thing. |
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Anonymous | yur 17 and u havent taken geometry yet...wow...im 17 and im taking AP calculus... |
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Gold Member Username: InvainMichigan United States Post Number: 3310 Registered: Aug-04 | You do understand that some schools have their math courses in different order? Even though most schools have Geometry right after Algebra I, some do have it later instead. |
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Silver Member Username: CenusHicksville, Ohio Usa Post Number: 326 Registered: Jan-05 | ya i'm only in the 10th grade, and in our school it goes algbra 1, geometry, algebra 2, pre-calculuss, calculuss. and plus i had to retake pre-algebra so that put me behind even more. |
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Bronze Member Username: Infinity_addictSanta Rosa, California USA Post Number: 41 Registered: Jul-05 | watch your backs, people - we have a genius on our hands! anonymous is almost TOO smart! who brags about their math class? yes, dividing by 1728 would be correct, and make sure you measure by the inside dimensions of the box. good luck fellow DIYer! |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 300 Registered: May-05 | Dustin, if i remember correctly, you never mentioned what sub this was. Most companies give you the gross recommended volume, which already takes into account the volume of the woofer. Also, this is a gigantic box. You should probably port this. Since its a 15, I'm guessing your not trying to set any records for sq, so you might as well port it. Most people find ported boxes better (aka louder). Anyway, if you were to make a trapazoid box, what you'll have is a different depth for the box depending on if you measure it at the top or bottom or anywhere in between. For calculating volume, average the depth at the top and the depth at the bottom and pretend that the number you calculated is the same as the depth for a rectangluar box. |
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Silver Member Username: CenusHicksville, Ohio Usa Post Number: 327 Registered: Jan-05 | well would port it but i have 2 subs and space is kinda small, going in the back of a jeep, the sub is a Ascendant audio atlas so i hope it has good sq. and on the site it was recomenneding boxes with 6 cubic feet, but there is no way i can go that big. how deep should i make to box, just enough to clear the magnet, or should i make it deeper so it can cool off a little bit more. |
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Bronze Member Username: JechapkPost Number: 14 Registered: Jun-05 | yeah i took ap cal at 15 because the stupid school didnt let me take it until 11th grade ;[ make the box as big as you can...from what i hear unless it is 3 or 4 times over recommended size it doesnt matter.... |
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Silver Member Username: CenusHicksville, Ohio Usa Post Number: 335 Registered: Jan-05 | BUMP |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 309 Registered: May-05 | an inch or so of breathing room wouldn't be a bad idea. Plus, if this is your first box, you don't want to leave "just enough to clear the magnet" because undoubtedly, something will be off by a quarter inch and the sub no longer fits. |
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Silver Member Username: LettoMilwaukee, WI Post Number: 105 Registered: Jun-05 | What is this world coming to when people start bragging about their Math classes... Especially in a forum with people like myself (an engineering major with a math minor) that have taken more Math than most people care to think about. |
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Bronze Member Username: HalbyParsippany, NJ Post Number: 76 Registered: Jun-05 | Word Letto same here, I feel ya. |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 312 Registered: May-05 | anyone else find that ironic?  |
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Silver Member Username: CenusHicksville, Ohio Usa Post Number: 341 Registered: Jan-05 | ya just a little bit, but thanks for the advice i'll start building the boxes as soon as i get some mdf board, i'll post some pics when i get done but that may be a while. ohh would i notice a difference if i used 1 inch mdf board or would 3/4 be good enough. |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 314 Registered: May-05 | 3/4" might be a little thin for a 3 cubic ft. box but if its well braced you'll be fine. |
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Silver Member Username: CenusHicksville, Ohio Usa Post Number: 345 Registered: Jan-05 | well i'll just go with 1 inch just to be safe. |
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New member Username: Modder05Brooklyn, Oh Post Number: 4 Registered: Jul-05 | 3/4" MDF properly glued and sealed will do you you plenty of justice....box design of that caliber should be constructed as a wedge.....if you are having a hard time with the measurements then try a program like Probox5....its cheap, downloadable and simple to use.....ebay has a downloadable version for 3.00....if you order it punch in these figures and it will give you a wedge box that has a volumn of 2.98..(W-25", D-24", H-18", Top-8.25", 3/4"mdf board) you can play around with those figures based on clearance in your car or truck! And it will also give you a breakdown of each peice to cut, and what dimensions to cut them at! Good Luck! |
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Gold Member Username: Jonathan_fGA USA Post Number: 4329 Registered: May-04 | bcae offers a free box tutorial. http://www.bcae1.com/spboxnew2.htm Just play around with it until you get the dimensions needed to fit, it's very straightforward. 3/4" would work, but bracing is always a good thing, you could either brace, or you could build from 1", or use 1" and brace (<- best thing). |
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Silver Member Username: CenusHicksville, Ohio Usa Post Number: 350 Registered: Jan-05 | cool thanks for the site its very helpfull |
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