i have the jl w0 and the jl w1 right now but i will soon be getting 2 more w1's. i want to build a ported box that will fit my trunk of my 97 cougar (big trunk). in the owners manual for the w1 that i have. it says to make a 1.75cu.ft. box per sub with a slot port of 1.5in X 14.5in X 33.75in (slot width x slot hight x slot length).
on rockford.com they have a box calculator. i figured that my box would have to be 14in X 33in X 33in (Height X width X depth) with 3/4" MDF, to give me 7.2 cu.ft., about 1.75 cu.ft.per side to fit my trunk. i want to divide the box in half and have 2 subs per side. i want to know how big to make my port? i may be able to make my box higher so i can have the port 14.5in in hight. i like to listen to all kinds of music but now that i have the subs i like alot of rap and r&b, beacuse of the bass. in the manual it says when using 2 subs double the volume and in the case of a ported box use 2 times the ports. can i make my port 3 inches wide? when using the 2 subs on one side.
if there is anything i missed or left out just let me know ? its my first box but i will be making it with a friend.
Replies (7)
swez on 03/21/2006 19:19:26
Frankly, I would not build a banger sub system around either of the JL subs mentioned. The are only 125 watts RMS per sub. The 7.+ cf box will be "very heavy" and a major gut buster to install. If you had a cargo van or large SUV, well... maybe.
Also, the subs will probably have to fire upward toward the truck lid too. This stinks because you'll need a ton of dampening material to quiet the trunk lid down. Not to mention, up firing subs with minimal airspace between cones and metal trunk lids, just don't breath as well as rear fired subs. in a trunk loaded sedan or hardtop.
Trust me on this one. I had an Olds Trofeo' before and it too had a large trunk. I tried several sub firing orientations. The up firing was the worst and rear firing was best by far.
Finally, what kind of amp are you planning to use to power your subs? Make, model and RMS power would be most helpful here.
Swez
PS Believe what you like, but most of old timers here, know that 1 or 2 strong subs in a well designed enclosure, can easily out-perform a 4 sub system. (lots of cancellation issues are probable) Using minimal amounts of space and weight, the car rides and sound will be better too. Let Victor comment too. Am sure he will have some key thoughts about your present plans as well.
ckoscin2 on 03/22/2006 21:34:04
i have a crossfire cfa-1000d(mono block), 1000w X 1 rms at 1 ohm. i have 2 now that are the svc 4 ohm, so with 4 of the subs i would be at 1 ohm.
i have enought room for a 3 foot by 3 foot box. and for 15-17 inches of height. i wanted to fire the subs up with the ports facing twards the back of the car. i figured that i would have +/- 2 inches of space inbetween the box and top of the trunk. i already have some stinger dampening material on my trunk lid but i was looking into the dynamat trunk kit. i have a friend that has 4 w0's in his grand prix facing up and they are loud in his car but it does rattle alot(sealed box).
i already have the two subs, and at the local shop i get them for $100 a pice. i have the 200 so i can get the two more. i now have the 2 subs and i am kind of stuck with them and i want it to be a lil louder. i figure that i am about 125-135 db and my last system was about 143-145 db. i just want a way to get it a lil bit louder and i figured more subs and more power.
swez on 03/22/2006 23:45:06
Sorry, but I don't think your going to get the best results with this present plan. Ports will only put out sonic energy, near the port tuning frequency. Above that, it's all cones doing the work.
Having less than a foot of clearance between subs and rear deck or trunk lid, makes the bass waves bounce off the trunk or rear deck and right back into the sub cones. This will cancel out a lot of Bass SPL and you'll be very dissappointed. NOT A GOOD PLAN!
That Crossfire amp is very strong too. (typically under-rated too) These JL subs are rated at 125 watts RMS. So, at 1 ohm, each sub will get 250 + watts RMS. In a ported box, they will not handle that kind of power at all. It will rip them apart when you wang em hard.
If you really want some beast bass back there, consider a pair of strong 12's or even a pair of 15's. A pair of Alpine SWR-1242's can handle 1000 watts RMS and can be had for under $150.00/each, if you shop them hard. This is an SQL sub, good efficiency and very solid bass in a small, ported enclosure too. This way, the box is smaller, lighter, takes more RMS power and you will not shread these subs easily.
http://www.pricegrabber.com/p__Alpine_Alpine_Type_R_SWR_1242D_12_Dual_4_ohm_
Component_Subwoofer_12_Component_
Subwoofers,__6620348/skd=1/search=alpine+1242
($117.00 each + S/H) A great price for a very good sub.
Think about it OK? The old man knows his business and would never steer ya wrong.
Swez
ckoscin2 on 03/23/2006 02:49:23
ok i see what u mean. if i were to build a ported box for my 2 subs that i have now would that be any better then the small sealed box that i have now? how would a ported box sound different then my sealed one ? can i make the port longer or shorter to the the better bass that i want when i listen to alot of rap? what happends when u make a port longer or shorter, what will it sound like?
swez on 03/23/2006 12:15:26
Yes, it would give you a nice low end bump at the port tuning frequency desired. I would suggest you follow the JL ported enclosure specs as noted below:
http://mobile.jlaudio.com/products_subs_pages.php?page_id=15
Also, these subs (12W0 & 12W1) are very similar. They both spec a ported box with an internal air space of 2.5 cf per sub. This will mean a pretty large box for the pair. I would target tuning frequency to 35-38 Hz. The port diameter, length and box internal air space will determine your port dimensions.
Use this calculator to help you design the box that will fit in your space. Figure a min height of 14" to allow for ease of installing rear firing sub and ports. The width and depth dimensions can be manipulated to hit a target between 2.0-2.5 cf/sub chamber.
http://www.the12volt.com/caraudio/boxcalcs.asp
The general specs I can see would be like this: (These are external dimensions with 3/4" MDF, and a center baffle divider between chambers.)
Height: 14.0"
Width: 30.0"
Depth: 24.0"
Net internal volume: 4.64 cf (minus ports and sub displacements)
That's ~2.15 cf per sub chamber when done.
Use a pair of 4" dia (round) ports, 8.0" long. This nets a tuning frequency target of 38 Hz. (one port per sub chamber)
NOTE: When using ported designs, always use a Sub Sonic Filter to protect your subs. This blocks harmful low frequency energy, below the port tuning frequency. (PTF) Here, an SSF targeted between 35-40 Hz., is fine.
???: Do you know the voice coil ohmic ratings on the subs you have now? They came in 4 & 8 ohm SVC's in these models. It's important to know which values they are and match. (Ie: a pair of 4 ohm coils, or a pair of 8 ohm coils)
12Wx - 4 = 4 ohm coil
12Wx - 8 = 8 ohm coil
Once we confirm this info, amping power will be addressed. Do you have a link to specs on that Crossfire amp noted earlier?
Swez
ckoscin2 on 03/27/2006 03:14:54
well swez thanks for all the help and i was looking on ebay last night and found a kicker 15" l7 that i got for under my $200 budget.
i have some questions about porting options and i will just make another tread about it. and i will be soon selling my JL's....
swez on 03/27/2006 09:27:24
Good choices here. You get the bump your missing now. The JL subs mentioned are great SQ subs for low powered systems. But for some heavy bumping, the L7 15 will get ya there, with a strong amp.
They have box design info on the Kicker site. Have a look and figure out the size you need. www.kicker.com
Swez
on rockford.com they have a box calculator. i figured that my box would have to be 14in X 33in X 33in (Height X width X depth) with 3/4" MDF, to give me 7.2 cu.ft., about 1.75 cu.ft.per side to fit my trunk. i want to divide the box in half and have 2 subs per side. i want to know how big to make my port? i may be able to make my box higher so i can have the port 14.5in in hight. i like to listen to all kinds of music but now that i have the subs i like alot of rap and r&b, beacuse of the bass. in the manual it says when using 2 subs double the volume and in the case of a ported box use 2 times the ports. can i make my port 3 inches wide? when using the 2 subs on one side.
if there is anything i missed or left out just let me know ? its my first box but i will be making it with a friend.
Replies (7)
swez on 03/21/2006 19:19:26
Frankly, I would not build a banger sub system around either of the JL subs mentioned. The are only 125 watts RMS per sub. The 7.+ cf box will be "very heavy" and a major gut buster to install. If you had a cargo van or large SUV, well... maybe.
Also, the subs will probably have to fire upward toward the truck lid too. This stinks because you'll need a ton of dampening material to quiet the trunk lid down. Not to mention, up firing subs with minimal airspace between cones and metal trunk lids, just don't breath as well as rear fired subs. in a trunk loaded sedan or hardtop.
Trust me on this one. I had an Olds Trofeo' before and it too had a large trunk. I tried several sub firing orientations. The up firing was the worst and rear firing was best by far.
Finally, what kind of amp are you planning to use to power your subs? Make, model and RMS power would be most helpful here.
Swez
PS Believe what you like, but most of old timers here, know that 1 or 2 strong subs in a well designed enclosure, can easily out-perform a 4 sub system. (lots of cancellation issues are probable) Using minimal amounts of space and weight, the car rides and sound will be better too. Let Victor comment too. Am sure he will have some key thoughts about your present plans as well.
ckoscin2 on 03/22/2006 21:34:04
i have a crossfire cfa-1000d(mono block), 1000w X 1 rms at 1 ohm. i have 2 now that are the svc 4 ohm, so with 4 of the subs i would be at 1 ohm.
i have enought room for a 3 foot by 3 foot box. and for 15-17 inches of height. i wanted to fire the subs up with the ports facing twards the back of the car. i figured that i would have +/- 2 inches of space inbetween the box and top of the trunk. i already have some stinger dampening material on my trunk lid but i was looking into the dynamat trunk kit. i have a friend that has 4 w0's in his grand prix facing up and they are loud in his car but it does rattle alot(sealed box).
i already have the two subs, and at the local shop i get them for $100 a pice. i have the 200 so i can get the two more. i now have the 2 subs and i am kind of stuck with them and i want it to be a lil louder. i figure that i am about 125-135 db and my last system was about 143-145 db. i just want a way to get it a lil bit louder and i figured more subs and more power.
swez on 03/22/2006 23:45:06
Sorry, but I don't think your going to get the best results with this present plan. Ports will only put out sonic energy, near the port tuning frequency. Above that, it's all cones doing the work.
Having less than a foot of clearance between subs and rear deck or trunk lid, makes the bass waves bounce off the trunk or rear deck and right back into the sub cones. This will cancel out a lot of Bass SPL and you'll be very dissappointed. NOT A GOOD PLAN!
That Crossfire amp is very strong too. (typically under-rated too) These JL subs are rated at 125 watts RMS. So, at 1 ohm, each sub will get 250 + watts RMS. In a ported box, they will not handle that kind of power at all. It will rip them apart when you wang em hard.
If you really want some beast bass back there, consider a pair of strong 12's or even a pair of 15's. A pair of Alpine SWR-1242's can handle 1000 watts RMS and can be had for under $150.00/each, if you shop them hard. This is an SQL sub, good efficiency and very solid bass in a small, ported enclosure too. This way, the box is smaller, lighter, takes more RMS power and you will not shread these subs easily.
http://www.pricegrabber.com/p__Alpine_Alpine_Type_R_SWR_1242D_12_Dual_4_ohm_
Component_Subwoofer_12_Component_
Subwoofers,__6620348/skd=1/search=alpine+1242
($117.00 each + S/H) A great price for a very good sub.
Think about it OK? The old man knows his business and would never steer ya wrong.
Swez
ckoscin2 on 03/23/2006 02:49:23
ok i see what u mean. if i were to build a ported box for my 2 subs that i have now would that be any better then the small sealed box that i have now? how would a ported box sound different then my sealed one ? can i make the port longer or shorter to the the better bass that i want when i listen to alot of rap? what happends when u make a port longer or shorter, what will it sound like?
swez on 03/23/2006 12:15:26
Yes, it would give you a nice low end bump at the port tuning frequency desired. I would suggest you follow the JL ported enclosure specs as noted below:
http://mobile.jlaudio.com/products_subs_pages.php?page_id=15
Also, these subs (12W0 & 12W1) are very similar. They both spec a ported box with an internal air space of 2.5 cf per sub. This will mean a pretty large box for the pair. I would target tuning frequency to 35-38 Hz. The port diameter, length and box internal air space will determine your port dimensions.
Use this calculator to help you design the box that will fit in your space. Figure a min height of 14" to allow for ease of installing rear firing sub and ports. The width and depth dimensions can be manipulated to hit a target between 2.0-2.5 cf/sub chamber.
http://www.the12volt.com/caraudio/boxcalcs.asp
The general specs I can see would be like this: (These are external dimensions with 3/4" MDF, and a center baffle divider between chambers.)
Height: 14.0"
Width: 30.0"
Depth: 24.0"
Net internal volume: 4.64 cf (minus ports and sub displacements)
That's ~2.15 cf per sub chamber when done.
Use a pair of 4" dia (round) ports, 8.0" long. This nets a tuning frequency target of 38 Hz. (one port per sub chamber)
NOTE: When using ported designs, always use a Sub Sonic Filter to protect your subs. This blocks harmful low frequency energy, below the port tuning frequency. (PTF) Here, an SSF targeted between 35-40 Hz., is fine.
???: Do you know the voice coil ohmic ratings on the subs you have now? They came in 4 & 8 ohm SVC's in these models. It's important to know which values they are and match. (Ie: a pair of 4 ohm coils, or a pair of 8 ohm coils)
12Wx - 4 = 4 ohm coil
12Wx - 8 = 8 ohm coil
Once we confirm this info, amping power will be addressed. Do you have a link to specs on that Crossfire amp noted earlier?
Swez
ckoscin2 on 03/27/2006 03:14:54
well swez thanks for all the help and i was looking on ebay last night and found a kicker 15" l7 that i got for under my $200 budget.
i have some questions about porting options and i will just make another tread about it. and i will be soon selling my JL's....
swez on 03/27/2006 09:27:24
Good choices here. You get the bump your missing now. The JL subs mentioned are great SQ subs for low powered systems. But for some heavy bumping, the L7 15 will get ya there, with a strong amp.
They have box design info on the Kicker site. Have a look and figure out the size you need. www.kicker.com
Swez
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