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Bronze Member Username: Oaklandraider87Post Number: 13 Registered: Jul-04 | Im gettin 2 12" Brahmas to put in my 94 Ford Explorer and I want to know the best box type and box size for the greatest spl and also sq. Also will I only need one JBL 1200.1 amplifier or will I need to get two, one for each sub, and how will I need to wire both subs. |
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Silver Member Username: SouthernrebelLouisiana USA Post Number: 108 Registered: Mar-04 | One JBL 1200.1 will work. try bout a 2-2.5 cuft per sub vented box tuned to 28hz...that will sound good... |
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New member Username: Rwmj5Post Number: 3 Registered: Aug-04 | You're lucky- you can hook your subs up as a 2 ohm load since you have two. You want to wire the two terminals on each sub in series, and then wire the two subs in parallel to your amp, giving you a 2 ohm load and 1200 watts total to both subs. It would look like the last wiring diagram on this page: http://www.adireaudio.com/Files/TechPapers/DualVoiceCoilWiring.pdf |
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Bronze Member Username: Oaklandraider87Post Number: 14 Registered: Jul-04 | ok.... how do you tune a box to certain hz |
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Gold Member Username: Jonathan_fGA USA Post Number: 1030 Registered: May-04 | It depends on the surface area of the port, generally, it gets more complicated. Go here: http://www.bcae1.com/spboxnew2.htm and play around with it. To make it easy on you, Adires specs call for this: For more SQ: 2.0 cubic foot net, 28 hz tune. 14.5"x14.5"x18" internal, port 4" Inside diameter and 17" long. More SPL, still good SQ: 3.0 cubic foot net, 35 hz tune. 16.5"x16.5"x20" internal, Dual 4" Inside diameter ports, both 14" long. |
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Bronze Member Username: Oaklandraider87Post Number: 16 Registered: Jul-04 | ok, im prolly gonna go wit the 3 cubic foot box, i wanted to know what the size of a slot vent would be the best, and does it matter where it is placed on the box? |
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Bronze Member Username: Oaklandraider87Post Number: 17 Registered: Jul-04 | or should i go with tubular ports, which ones are better or are they both equal |
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Silver Member Username: JmloughreyFarmington, CT Post Number: 117 Registered: Jul-04 | i've heard the same subs with both slot ports and tube ports...personally, i feel a ports a port |
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Gold Member Username: Jonathan_fGA USA Post Number: 1103 Registered: May-04 | As long as the surface area is the same, and the round port is filed so that you don't get port noise (can be a whistling sort of sound) you'll be ok. I prefer slot ports. To calculate a slot port from a round, what you do is match the slot port's surface area (the surface area of the opening) with the equivalent round port's opening. For example, for that 3.0 cubic foot box, it requires 2 4" round ports. The surface area of a round port is found by diameter x pi(3.14). So take 8 inches, multiply by 3.14, and you'll get a surface area of 25.12. So for a slot port, you need a slot that will be 25.12 of surface area, 12.5" x 2" would be a good size slot port and equal around 25.12 sq inches. The length of the port would be the same as the round ports, added together since you have two, so the final slot port would be about 12.5x2 and 28 inches long. |
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Bronze Member Username: Oaklandraider87Post Number: 18 Registered: Jul-04 | ok, would you be able to draw up something on like photoshop of what the box should look like with dimesnsion because i am a little confused becasue you said it should be 28 in long but the box dimensions are 16.5"x16.5"x20" internal for 3 cubic feet, and is this the dimension for just one sub or two |
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Gold Member Username: Jonathan_fGA USA Post Number: 1118 Registered: May-04 | All you do is make an L, corner the slot basically. Make it 2" wide, for you, make the slot 14.5" long to the back, then 13.5" wide |
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Bronze Member Username: Oaklandraider87Post Number: 19 Registered: Jul-04 | ok, thx alot |
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Bronze Member Username: RedskinLondonEngland Post Number: 67 Registered: Dec-03 | Hmmmmmm.......to calculate the surface area of a circle is radius x radius x Pi. |