So here is the story........ I scored 4 JBL GT512's, and the prefab boxes I've been using simply are not cutting it.....
Moral of the story.... We need a super sick looking box (there will be plexi and lights involved, as well as being vinyl wrapped....), that will generate some great SPL, but still tuned nice and low so I get a good blend of quality with my schlumps.......
As for now, I have a pair of Alpine MRP-M500 amps, one for each pair of subs. Planning on changing that out very soon, but they will work for now. But due to this, I definitely want to have dual chambers, two subs per chamber.
I would run 4 chambers, but here is the story, we have 50 inches of width to get this beast in, but height and depth are pretty flexible. My only concerns are that all 4 subs and the ports are on the same plane, and fire rearward. I would like the height to be low enough so I can at least see over it when reversing.
This will take some clever packaging, and this is where my trusted enclosure masters are questioned as opposed to the "money first, sound second" attitude of my installers. I do have one guy who will be helping me without that attitude, but even he is at a draw for what to do port size and overall enclosure size. The packaging I can figure out, but I definitly want to make sure that you guys are in approval of the chambers, ports sub placement ect..
T/s Specs of the sub enclosure....
http://manuals.harman.com/JBL/CAR/Boxes%20and%20Parameters/GT512Tech_050108.pdf
Also includes manufacturers recommended enclosure which is the same for all of the JBL subs power series and under. I am more than sure that that will be going out the window with this design. I will also be upgrading eventually to the power series 12s, the P1222's, so I want to make sure that we leave enough room to widen the holes for the bigger 12s when I get them.
I measured the hatch opening of my Exploder and we have top center height of 33 inches, top width of 42 inches, bottom width of 50 inches. There is 53 inches of width inside the vehicle, and we will lose 4 inches of height due to the false floor that will cover up the arches so the floor is flat and grant me a small storage area.
So, here is a visual aid to what I kind of have in my head.....
its pretty rough, and doesn't quite express my desire for more width than height, but still easier than explaining the box's front. also, top and front panels will be 1 inch mdf due to plexi use.....
Let me know what you boys think... I trust my system, which is currently pretty weak for all the gear I have procured, but now that there is some sort of finality in what number of subs I am going to be running, its time to build something so my boss will let me open up my trunk when were showing off our cars to build customers......
Replies (20)
swez on 04/4/2009 12:43:41
It appears your new box will be over 8ft^3 when calculating port and sub displacements. (1.75 cf per sub)
To get a good feel for the front panel dimensions, it might be a good idea to break out a large sheet of cardboard and outline the subs as noted. That will tell you the min H & W of the box and the rest can be made up by adjusting the D part of the equation.
The outer dimensions of these subs are 12-5/16". Adding a little space should help when you upgrade to the Power Series later.
Also, since this box will be large and only 2 chambers, consider using 1" MDF for this build to prevent panel rattles and resonances. Any panels longer that 18" may need some bracing. Consider triangle type braces as these take up the least amount of internal airspace.
Looks like a fun project in the works,
Swez
PS Watch the shop talk Thump... we are a PG rated site OK. Please edit if you can.
Victor on 04/4/2009 14:37:10
Yes sure looks like a fun project..
You want a low tuned BP... gonna be bigger than manufacturer specs...
I would recommend a Vr of 1.25 cu.ft and a Vf of 1.75 cuft and a port tuned to 40Hz ....per sub....
All this cud be done in 42" x 42" x 17" external volume...... have done a rough sketch on paper... don't have time to scan or redraw on the computer... will do it once i get time on sunday ( tomorrow )
Victor...
SQLThump on 04/4/2009 18:09:25
Ooooops...... my bad coach........
So, Trying to avoid bandpass, I do want a lot of SPL, but I do not want to to sacrifice quality........ thats why i was thinkin ported tuned low........ like 33-35hz or so.......
Good call on the cardboard template Swez.......cant believe i didn't think of that.....
swez on 04/5/2009 01:26:42
The BP plots for these subs are not as narrow as some I have seen, but if you went that route, the rear section is 1.0 cf and the front section is 1.25 cf/sub. (Huge box)
As for the cardboard template idea, some guys build a full scale model in carboard just to see if the plan will work and the box will fit in the space available. It's a lot less time and $$ to invest than building a great box that won't fit when assembly is completed.
In fact, you may find the need for a 2-stage enclosure. One section for the subs and a lower shelf for the ports/airspace that allows you to mount the amps on the lower stage as well.
Think about that OK?
Swez
newB on 04/5/2009 21:32:38
Whoa! sorry i missed this thread GRIN
seems like the first step has been pinne down- any update?
**Edit**are you trying to wall your explorer with four 12s?!?!?
-Drew
SQLThump on 04/5/2009 22:10:25
Noobster...... i was actually waiting on your take on this subject before i do anything, i am looking for similar results to your car, been sold since the floating trash vid.....
definitly dont want to wall it, need a kenwood dnx8120 with a cam before i even think of walling, park in way too many narrow spaces and drive too crazy not to have rearview
mainly the goal is a box that will give as much spl at as deep a tuning as possible.
enclosure specs from jbl on these subs suck...... its the same for all of harman kardons car lineup, and it isnt that great for any of them....
i need a sick enclosure like you design, a mean ported spl enclosure
let me know what you think man
newB on 04/5/2009 22:16:31
What year of explorer? 2dr or 4dr? see my thread "still on top" for pics of the setups i've been doing in a 2002 Explorer 2dr sport.
the 2dr and 4dr are completely different and will change things a little.
lastly, what alignments have you tried?
-Drew
SQLThump on 04/5/2009 22:30:50
its a 94 4door, definitly want my rear seats, as long as i can see over the top of the box the whole rear hatch is fair game, being its the whole reason i bought an explorer.
only two rows of seats, im going to do a false floor to flatten the floor due to the tire wells...
currently i havent even tried a custom enclosure, the ported prefabs ive been running are about 1.5 cubes, tuned around 45hz. they sounded great when they were rear firing, but in their currently upfiring form they sound like crap...
so i need to do something soon, i went from 2-4 12s and doubled power, but i didnt get my 6dbs and im pretty mad about it for sure...
so what your thoughts man??? i just know i want to rearfire all 4 12s for sure, it definitly sounds best in the exploder...
also, excuse my total wanton disregard for spelling and grammar, all i got is mobile web right now, and its too much effort...
newB on 04/5/2009 23:01:29
Awesome!
i cant quite imagine your "false" floor yet- but this is my first thought.
your going to want to go max width between wheel wells, and max height to window line. Then use the depth dimension as your variable to get the desired internal volume.
For alignment, you want all four woofers up firing with rear firing aeros or a center slot vent
i dont have MY computer or i'd draft you up something. i'll keep ya posted
-Drew
SQLThump on 04/5/2009 23:57:11
so no ideas on where to go on volume or port size?
newB on 04/6/2009 00:31:34
I would do 7cubes for all four or two 3.5 chambers with ~50 square inches of port per half or 100 for a single chamber.
Your cabin gain will be low- tune to 37-38 and you will have strong output for bass race or burps (low/mid40s for burps Young Jeezy ~40hz for bass race) and still give you tons of musical range down to the low 30s
do you have a preference for slot vent or round ports?
-Drew
SQLThump on 04/6/2009 18:37:02
I was thinking of going with slot ports on thisone here.... two chambers sounds good too, let me know what port dimensions to work, I can figure out dimensions for the airspace....
SQLThump on 04/13/2009 13:42:52
Update....kind of
Vic, I could not download those BP specs, could you repost them??
I had one of the 4 12's wired out of phase, explaining the lack of SPL and sloppy bass, I fired all 4 subs rearward and from there it has made for a window flexin' SPL monster, still want to get the custom box built though.......
One thing that I realize sucks about having asystem this insanly loud...... people hate me..... There has been a fair amount of saliva deposited rather grossly on various windows on my vehicle, and driving 85 down the freeway its still loud enough to irritate everybody in traffic.......Pretty unfortunate considering there is like nowhere I can go to bumpout while being considerate to other drivers......and I am in the hobby to enjoy my system, not to make sure hundreds of others hate it....
I cant imagine enough sounddeadening on earth to keep all of that bass in......
Victor on 04/13/2009 17:09:02
Here you go...
http://www.box.net/shared/0rmef9t8ma
BOOM RESPONSIBLY .. COFFEE
newB on 04/14/2009 04:22:55
Yeah i feel your pain man.
The 150+ Explorer i just did is "downgrading" because he has four cracks in his roof, crunched suspension, cracked windshield, cracked window grips, and finally his tires are wearing funny because of the added weight.
Did i miss pix? shoot me a link if you can.
-Drew
SQLThump on 04/14/2009 20:33:59
Cracks in the roof?? From flexing it or what?? Sounds like you need more sound insulation...
As for the crunched suspension, is that from all the extra weight? My old suspension acrually rides better loaded down, and is loving the subs, especially in the snow, having that much extra weight over the rear axle makes for some mad traction......
fortunatly, I have a fair amount of sound insulation, I do need more, but breaking and cracking stuff hasn't yet been an issue. As for my rear wiper and hatch handle, they sound like they are about to take off flying, and my rear side windows flex like crazy....
My main thing is the dirty looks and fingers I recieve here in Boulder... Most green freaks and hippies have some mad hatred for an Explorer to start with, let alone a very loud Explorer.
I think I need to move to a more car audio freindly part of the country, because the scene here pretty much consists of me and my freinds for hardcore bassheads, and all of the other car culture around here (which WAS awesome) has pretty much gone flat thanks to the ban on cruising...
I didn't take any pictures yet, but I can if you want.... I just havent really changed anything since post except the box arrangment and the out of phase sub..
figured you need to build something before you take buils picsGRIN
As for your buddy, tell him to get tougher shocks, tires and more insulation, upgrading is always better than downgrading.....
Still trying to come up with perfect enclosure dimensions, having 4 rear firing 12's on the same plane with the ports and being to see over the box wasn't as easy as i thought....
SQLThump on 05/5/2009 18:08:47
Well, the 4 12's didn't last long...
I had to sell 2 of them to make rent.... I am truly crushed....
And so is the explorer.... my car suffered from some mad player-hatred... all of my tires have nails in them, and I pretty much quit playing it in any city due to unwanted attention....
Even on the freeway, it turned a lot of heads, and drew many headshakes, middle fingers and otherwise... Did get a few people loving it though....
The exploder is driving like a 4.0L V-6 dumpster, complete with thumping audio system..... My front end is about to fall apart..the rear suspension is dusted from all the weight...all my tires are near shot...my transmission is slipping like crazy, and my engine is running on 3 hampsters tops...
At this point, all audio projects are sidelined until i get my suspension, transmission, and tire issues taken care of.... then I'm getting a new deck..... After a nice round of engine upgrades I'm going to insulate the hell out of the car so most of the unwanted attention can
swez on 05/5/2009 18:42:58
Sounds like the hood hates bassheads?
Well, we can't blame others for not enjoying our habits and preferences and loud music with a ton of bass even bugs me if the guy is being a jerk. Hey, I'd like to hear my music or a talk show w/o competing with some idiot some 200 feet away as he bangs his subs all over town.
The part about taking it out on your ride is not a cool thing, but I can see some getting a dope slap or two for not reaspecting others rights to P&Q. (Peace and Quiet) I usually just ask politely to dial back on the SPL and most of the time, they do... but the evil twin in me would like to take a hammer to their rig and the nut job making all the noise. (No joke!) Some folks find this an intrusion on their personal space and will take drastic measures to stomp out the noise.
Sorry to hear of your woes,
Swez
PS Are you still working for BB?
SQLThump on 05/5/2009 20:03:18
Cartoys..... Best Buy barely even counts as competition...
The hood loves the stereo...the city I live in has much respect for its biggest basshead... The city I work in, not so much.
I tried to be considerate, but there is no being considerate with that much SPL and that little insulation... I defintly wasnt parking lot pimpin irratitating people on purpose, It just sucked to find my favorite bumpin escape (interstates) wasnt good enough anymore...
newB on 05/6/2009 16:40:42
That sucks man!! Explorers are the CRX of SUVs but they don't take the abuse for very long before some serious problems. I'd be thankful there is a serious amount of available parts for ploders.
Step back, get everything taken car of, and hit it hard once again GRIN
BTW, he has about 1/2" of Spectrum Sludge on the whole roof. Stuff happens when your moving two 18s with 8,000wrms haha
-Drew
Moral of the story.... We need a super sick looking box (there will be plexi and lights involved, as well as being vinyl wrapped....), that will generate some great SPL, but still tuned nice and low so I get a good blend of quality with my schlumps.......
As for now, I have a pair of Alpine MRP-M500 amps, one for each pair of subs. Planning on changing that out very soon, but they will work for now. But due to this, I definitely want to have dual chambers, two subs per chamber.
I would run 4 chambers, but here is the story, we have 50 inches of width to get this beast in, but height and depth are pretty flexible. My only concerns are that all 4 subs and the ports are on the same plane, and fire rearward. I would like the height to be low enough so I can at least see over it when reversing.
This will take some clever packaging, and this is where my trusted enclosure masters are questioned as opposed to the "money first, sound second" attitude of my installers. I do have one guy who will be helping me without that attitude, but even he is at a draw for what to do port size and overall enclosure size. The packaging I can figure out, but I definitly want to make sure that you guys are in approval of the chambers, ports sub placement ect..
T/s Specs of the sub enclosure....
http://manuals.harman.com/JBL/CAR/Boxes%20and%20Parameters/GT512Tech_050108.pdf
Also includes manufacturers recommended enclosure which is the same for all of the JBL subs power series and under. I am more than sure that that will be going out the window with this design. I will also be upgrading eventually to the power series 12s, the P1222's, so I want to make sure that we leave enough room to widen the holes for the bigger 12s when I get them.
I measured the hatch opening of my Exploder and we have top center height of 33 inches, top width of 42 inches, bottom width of 50 inches. There is 53 inches of width inside the vehicle, and we will lose 4 inches of height due to the false floor that will cover up the arches so the floor is flat and grant me a small storage area.
So, here is a visual aid to what I kind of have in my head.....
its pretty rough, and doesn't quite express my desire for more width than height, but still easier than explaining the box's front. also, top and front panels will be 1 inch mdf due to plexi use.....
Let me know what you boys think... I trust my system, which is currently pretty weak for all the gear I have procured, but now that there is some sort of finality in what number of subs I am going to be running, its time to build something so my boss will let me open up my trunk when were showing off our cars to build customers......
Replies (20)
swez on 04/4/2009 12:43:41
It appears your new box will be over 8ft^3 when calculating port and sub displacements. (1.75 cf per sub)
To get a good feel for the front panel dimensions, it might be a good idea to break out a large sheet of cardboard and outline the subs as noted. That will tell you the min H & W of the box and the rest can be made up by adjusting the D part of the equation.
The outer dimensions of these subs are 12-5/16". Adding a little space should help when you upgrade to the Power Series later.
Also, since this box will be large and only 2 chambers, consider using 1" MDF for this build to prevent panel rattles and resonances. Any panels longer that 18" may need some bracing. Consider triangle type braces as these take up the least amount of internal airspace.
Looks like a fun project in the works,
Swez
PS Watch the shop talk Thump... we are a PG rated site OK. Please edit if you can.
Victor on 04/4/2009 14:37:10
Yes sure looks like a fun project..
You want a low tuned BP... gonna be bigger than manufacturer specs...
I would recommend a Vr of 1.25 cu.ft and a Vf of 1.75 cuft and a port tuned to 40Hz ....per sub....
All this cud be done in 42" x 42" x 17" external volume...... have done a rough sketch on paper... don't have time to scan or redraw on the computer... will do it once i get time on sunday ( tomorrow )
Victor...
SQLThump on 04/4/2009 18:09:25
Ooooops...... my bad coach........
So, Trying to avoid bandpass, I do want a lot of SPL, but I do not want to to sacrifice quality........ thats why i was thinkin ported tuned low........ like 33-35hz or so.......
Good call on the cardboard template Swez.......cant believe i didn't think of that.....
swez on 04/5/2009 01:26:42
The BP plots for these subs are not as narrow as some I have seen, but if you went that route, the rear section is 1.0 cf and the front section is 1.25 cf/sub. (Huge box)
As for the cardboard template idea, some guys build a full scale model in carboard just to see if the plan will work and the box will fit in the space available. It's a lot less time and $$ to invest than building a great box that won't fit when assembly is completed.
In fact, you may find the need for a 2-stage enclosure. One section for the subs and a lower shelf for the ports/airspace that allows you to mount the amps on the lower stage as well.
Think about that OK?
Swez
newB on 04/5/2009 21:32:38
Whoa! sorry i missed this thread GRIN
seems like the first step has been pinne down- any update?
**Edit**are you trying to wall your explorer with four 12s?!?!?
-Drew
SQLThump on 04/5/2009 22:10:25
Noobster...... i was actually waiting on your take on this subject before i do anything, i am looking for similar results to your car, been sold since the floating trash vid.....
definitly dont want to wall it, need a kenwood dnx8120 with a cam before i even think of walling, park in way too many narrow spaces and drive too crazy not to have rearview
mainly the goal is a box that will give as much spl at as deep a tuning as possible.
enclosure specs from jbl on these subs suck...... its the same for all of harman kardons car lineup, and it isnt that great for any of them....
i need a sick enclosure like you design, a mean ported spl enclosure
let me know what you think man
newB on 04/5/2009 22:16:31
What year of explorer? 2dr or 4dr? see my thread "still on top" for pics of the setups i've been doing in a 2002 Explorer 2dr sport.
the 2dr and 4dr are completely different and will change things a little.
lastly, what alignments have you tried?
-Drew
SQLThump on 04/5/2009 22:30:50
its a 94 4door, definitly want my rear seats, as long as i can see over the top of the box the whole rear hatch is fair game, being its the whole reason i bought an explorer.
only two rows of seats, im going to do a false floor to flatten the floor due to the tire wells...
currently i havent even tried a custom enclosure, the ported prefabs ive been running are about 1.5 cubes, tuned around 45hz. they sounded great when they were rear firing, but in their currently upfiring form they sound like crap...
so i need to do something soon, i went from 2-4 12s and doubled power, but i didnt get my 6dbs and im pretty mad about it for sure...
so what your thoughts man??? i just know i want to rearfire all 4 12s for sure, it definitly sounds best in the exploder...
also, excuse my total wanton disregard for spelling and grammar, all i got is mobile web right now, and its too much effort...
newB on 04/5/2009 23:01:29
Awesome!
i cant quite imagine your "false" floor yet- but this is my first thought.
your going to want to go max width between wheel wells, and max height to window line. Then use the depth dimension as your variable to get the desired internal volume.
For alignment, you want all four woofers up firing with rear firing aeros or a center slot vent
i dont have MY computer or i'd draft you up something. i'll keep ya posted
-Drew
SQLThump on 04/5/2009 23:57:11
so no ideas on where to go on volume or port size?
newB on 04/6/2009 00:31:34
I would do 7cubes for all four or two 3.5 chambers with ~50 square inches of port per half or 100 for a single chamber.
Your cabin gain will be low- tune to 37-38 and you will have strong output for bass race or burps (low/mid40s for burps Young Jeezy ~40hz for bass race) and still give you tons of musical range down to the low 30s
do you have a preference for slot vent or round ports?
-Drew
SQLThump on 04/6/2009 18:37:02
I was thinking of going with slot ports on thisone here.... two chambers sounds good too, let me know what port dimensions to work, I can figure out dimensions for the airspace....
SQLThump on 04/13/2009 13:42:52
Update....kind of
Vic, I could not download those BP specs, could you repost them??
I had one of the 4 12's wired out of phase, explaining the lack of SPL and sloppy bass, I fired all 4 subs rearward and from there it has made for a window flexin' SPL monster, still want to get the custom box built though.......
One thing that I realize sucks about having asystem this insanly loud...... people hate me..... There has been a fair amount of saliva deposited rather grossly on various windows on my vehicle, and driving 85 down the freeway its still loud enough to irritate everybody in traffic.......Pretty unfortunate considering there is like nowhere I can go to bumpout while being considerate to other drivers......and I am in the hobby to enjoy my system, not to make sure hundreds of others hate it....
I cant imagine enough sounddeadening on earth to keep all of that bass in......
Victor on 04/13/2009 17:09:02
Here you go...
http://www.box.net/shared/0rmef9t8ma
BOOM RESPONSIBLY .. COFFEE
newB on 04/14/2009 04:22:55
Yeah i feel your pain man.
The 150+ Explorer i just did is "downgrading" because he has four cracks in his roof, crunched suspension, cracked windshield, cracked window grips, and finally his tires are wearing funny because of the added weight.
Did i miss pix? shoot me a link if you can.
-Drew
SQLThump on 04/14/2009 20:33:59
Cracks in the roof?? From flexing it or what?? Sounds like you need more sound insulation...
As for the crunched suspension, is that from all the extra weight? My old suspension acrually rides better loaded down, and is loving the subs, especially in the snow, having that much extra weight over the rear axle makes for some mad traction......
fortunatly, I have a fair amount of sound insulation, I do need more, but breaking and cracking stuff hasn't yet been an issue. As for my rear wiper and hatch handle, they sound like they are about to take off flying, and my rear side windows flex like crazy....
My main thing is the dirty looks and fingers I recieve here in Boulder... Most green freaks and hippies have some mad hatred for an Explorer to start with, let alone a very loud Explorer.
I think I need to move to a more car audio freindly part of the country, because the scene here pretty much consists of me and my freinds for hardcore bassheads, and all of the other car culture around here (which WAS awesome) has pretty much gone flat thanks to the ban on cruising...
I didn't take any pictures yet, but I can if you want.... I just havent really changed anything since post except the box arrangment and the out of phase sub..
figured you need to build something before you take buils picsGRIN
As for your buddy, tell him to get tougher shocks, tires and more insulation, upgrading is always better than downgrading.....
Still trying to come up with perfect enclosure dimensions, having 4 rear firing 12's on the same plane with the ports and being to see over the box wasn't as easy as i thought....
SQLThump on 05/5/2009 18:08:47
Well, the 4 12's didn't last long...
I had to sell 2 of them to make rent.... I am truly crushed....
And so is the explorer.... my car suffered from some mad player-hatred... all of my tires have nails in them, and I pretty much quit playing it in any city due to unwanted attention....
Even on the freeway, it turned a lot of heads, and drew many headshakes, middle fingers and otherwise... Did get a few people loving it though....
The exploder is driving like a 4.0L V-6 dumpster, complete with thumping audio system..... My front end is about to fall apart..the rear suspension is dusted from all the weight...all my tires are near shot...my transmission is slipping like crazy, and my engine is running on 3 hampsters tops...
At this point, all audio projects are sidelined until i get my suspension, transmission, and tire issues taken care of.... then I'm getting a new deck..... After a nice round of engine upgrades I'm going to insulate the hell out of the car so most of the unwanted attention can
swez on 05/5/2009 18:42:58
Sounds like the hood hates bassheads?
Well, we can't blame others for not enjoying our habits and preferences and loud music with a ton of bass even bugs me if the guy is being a jerk. Hey, I'd like to hear my music or a talk show w/o competing with some idiot some 200 feet away as he bangs his subs all over town.
The part about taking it out on your ride is not a cool thing, but I can see some getting a dope slap or two for not reaspecting others rights to P&Q. (Peace and Quiet) I usually just ask politely to dial back on the SPL and most of the time, they do... but the evil twin in me would like to take a hammer to their rig and the nut job making all the noise. (No joke!) Some folks find this an intrusion on their personal space and will take drastic measures to stomp out the noise.
Sorry to hear of your woes,
Swez
PS Are you still working for BB?
SQLThump on 05/5/2009 20:03:18
Cartoys..... Best Buy barely even counts as competition...
The hood loves the stereo...the city I live in has much respect for its biggest basshead... The city I work in, not so much.
I tried to be considerate, but there is no being considerate with that much SPL and that little insulation... I defintly wasnt parking lot pimpin irratitating people on purpose, It just sucked to find my favorite bumpin escape (interstates) wasnt good enough anymore...
newB on 05/6/2009 16:40:42
That sucks man!! Explorers are the CRX of SUVs but they don't take the abuse for very long before some serious problems. I'd be thankful there is a serious amount of available parts for ploders.
Step back, get everything taken car of, and hit it hard once again GRIN
BTW, he has about 1/2" of Spectrum Sludge on the whole roof. Stuff happens when your moving two 18s with 8,000wrms haha
-Drew
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