Home |
Search |
Today's Posts |
#1
|
|||
|
|||
unusual custom sub enclosure question
okay I've got the center console of a Jeep to use as a sub enclosure...
I've got an 8" JL 8W0 cocked at an angle roughly 45 degrees facing the lid of the console. The inside dimensions (aprroximate due to curves in the bottom) are 19" front to back, 8 3/4' wide by 7 3/4" deep. Not too drastically off from JL's recommendations. However the sub will not be firing out into the listening space, so I'm wondering what would be the best way to compensate for that and the fact that the enclosure is somewhat smaller than recommended and that the sub will be totally enclosed. I've got a 2 1/2" PVC vent that I can cut down (JL recommends 2 1/2" by 12.4 but that's in a bigger box). So my question is with a completely enclosed sub; should I use polyfill and a short vent, and where along the length of the console should I mount the sub (at one end or the other or in the middle?). Also should I face the sub towards the vent or away from it? If it sounds like crap I guess I'll end up getting a box and let it bang around, but there's no good place for a sub enclosure in a jeep, and hidden away inside the console is just too elegant to not at least try. -- Simon "I may be wrong, but I'm not uncertain." -- Robert A. Heinlein |
#2
|
|||
|
|||
unusual custom sub enclosure question
In article 3FFBCEFD.3030108@usefirstinitialandlastnameATerol s.com,
Simon Juncal wrote: okay I've got the center console of a Jeep to use as a sub enclosure... I've got an 8" JL 8W0 cocked at an angle roughly 45 degrees facing the lid of the console. The inside dimensions (aprroximate due to curves in the bottom) are 19" front to back, 8 3/4' wide by 7 3/4" deep. Not too drastically off from JL's recommendations. However the sub will not be firing out into the listening space, so I'm wondering what would be the best way to compensate for that and the fact that the enclosure is somewhat smaller than recommended and that the sub will be totally enclosed. I've got a 2 1/2" PVC vent that I can cut down (JL recommends 2 1/2" by 12.4 but that's in a bigger box). So my question is with a completely enclosed sub; should I use polyfill and a short vent, and where along the length of the console should I mount the sub (at one end or the other or in the middle?). Also should I face the sub towards the vent or away from it? If it sounds like crap I guess I'll end up getting a box and let it bang around, but there's no good place for a sub enclosure in a jeep, and hidden away inside the console is just too elegant to not at least try. I wouldn't use a port at all. It's asking for trouble when the box is undersized and conditions aren't perfect. Most likely it will leak out the low-end and buzz rather than create a mild resonation to help the lowest frequencies. It will sound really bad if it buzzes badly enough to make your CD player skip on certain notes. The only kind of port likely to help would be a long and fat pipe that adds to the box volume. A special speaker calculator is needed for ports that are large compared to the enclosure. I've seen them before online but don't remember where. It's probably more trouble than it's worth, especially when it comes to routing a giant port under the dash. Polyfill helps a sealed enclosure. BTW, I do hope you're talking about an inclosure installed inside the interior panels. The plastic panels alone won't hold much sound pressure, maybe only 35W average without breaking or hissing from air leaks. At least line it with fiberglass inside to stiffen it and form an airtight seal. |
#3
|
|||
|
|||
unusual custom sub enclosure question
It sounds like you must have an older TJ. Newer ones have a grill by the
drivers seat for the "optional" subwoofer. As the system in a TY is so crappy (I learned with my 2002) I did not order the upgraded system in my 2004. The center console still has the sub vent. You can pick up these on ebay pretty cheap. This weekend I will be installing an 8" Dayton Qu4tro Sub behind the grill. I am powering it with a Blaupunkt amp (SMALL size) that I hope to mount in the console. I hope for decent sound. Better than the crap DC sells in J**ps. I replaced the horrible stock speakers with the Infinities I bought for the 2002. The sub in the 2002 was lame at best. Hopefully this will be good enough. I do not want the sub in a box in back. The only option I see is the center console. Stop by a J**p dealer and look at the center console. It will make sense. "Simon Juncal" wrote in message news:3FFBCEFD.3030108@usefirstinitialandlastnameAT erols.com... okay I've got the center console of a Jeep to use as a sub enclosure... I've got an 8" JL 8W0 cocked at an angle roughly 45 degrees facing the lid of the console. The inside dimensions (aprroximate due to curves in the bottom) are 19" front to back, 8 3/4' wide by 7 3/4" deep. Not too drastically off from JL's recommendations. However the sub will not be firing out into the listening space, so I'm wondering what would be the best way to compensate for that and the fact that the enclosure is somewhat smaller than recommended and that the sub will be totally enclosed. I've got a 2 1/2" PVC vent that I can cut down (JL recommends 2 1/2" by 12.4 but that's in a bigger box). So my question is with a completely enclosed sub; should I use polyfill and a short vent, and where along the length of the console should I mount the sub (at one end or the other or in the middle?). Also should I face the sub towards the vent or away from it? If it sounds like crap I guess I'll end up getting a box and let it bang around, but there's no good place for a sub enclosure in a jeep, and hidden away inside the console is just too elegant to not at least try. -- Simon "I may be wrong, but I'm not uncertain." -- Robert A. Heinlein |
#4
|
|||
|
|||
unusual custom sub enclosure question
Kevin McMurtrie wrote:
I wouldn't use a port at all. It's asking for trouble when the box is undersized and conditions aren't perfect. Most likely it will leak out the low-end and buzz rather than create a mild resonation to help the lowest frequencies. It will sound really bad if it buzzes badly enough to make your CD player skip on certain notes. I'll try without the port first but I worry about the sub not having any access at all to outside air, all fully sealed boxes I've seen (where the sub is mounted entirely inside the box I forget what this mounting style is called), have had vents to let it push some outside air around. The only kind of port likely to help would be a long and fat pipe that adds to the box volume. A special speaker calculator is needed for ports that are large compared to the enclosure. I've seen them before online but don't remember where. It's probably more trouble than it's worth, especially when it comes to routing a giant port under the dash. Cool I'll do some googling and try to find it. Polyfill helps a sealed enclosure. BTW, I do hope you're talking about an inclosure installed inside the interior panels. The plastic panels alone won't hold much sound pressure, maybe only 35W average without breaking or hissing from air leaks. At least line it with fiberglass inside to stiffen it and form an airtight seal. I've got some thin MDF I was going to use, but fiberglass might be easier to deal with the curves. I hadn't thought about that thanks. -- Simon "I may be wrong, but I'm not uncertain." -- Robert A. Heinlein |
#5
|
|||
|
|||
unusual custom sub enclosure question
islandjeepman wrote:
It sounds like you must have an older TJ. Newer ones have a grill by the drivers seat for the "optional" subwoofer. As the system in a TY is so crappy (I learned with my 2002) I did not order the upgraded system in my 2004. The center console still has the sub vent. You can pick up these on ebay pretty cheap. Actually an 88 YJ. This weekend I will be installing an 8" Dayton Qu4tro Sub behind the grill. I am powering it with a Blaupunkt amp (SMALL size) that I hope to mount in the console. I hope for decent sound. Better than the crap DC sells in J**ps. I replaced the horrible stock speakers with the Infinities I bought for the 2002. The sub in the 2002 was lame at best. Hopefully this will be good enough. I do not want the sub in a box in back. The only option I see is the center console. I just put some decent Kenwood 4x6's in the dash (no fun getting those in) the boost in sound quality is amazing, good enough that I'm starting to think I might get this Jeep to actually not sound like a Jeep But that'll probably all go out the window once the hard top comes off and the noisy soft top goes on in the spring. Now all I have to figure out is where to put the damn amp, under the seat leaves it potentially exposed to water (hate to fry my amp the first time I get the Jeep stuck in mud up to the floorboards). Just about anywhere else I put it will be visible... Nothing screams "I have hundreds of dollars worth of stereo gear; steal it!" quite like a big colorful amp. That's another reason I want the sub in the console, and have relatively cheap Xplod 6x9's in the back enclosures. Stop by a J**p dealer and look at the center console. It will make sense. I know what you're talking about, there are aftermarket consoles that have sub woofer options too. I hadn't really thought about swapping a TJ console in, but if my little experiment fails that might be my next option. -- Simon "I may be wrong, but I'm not uncertain." -- Robert A. Heinlein |
#6
|
|||
|
|||
unusual custom sub enclosure question
In article 3FFC3E2A.2070204@usefirstinitialandlastnameATerol s.com,
Simon Juncal wrote: Kevin McMurtrie wrote: I wouldn't use a port at all. It's asking for trouble when the box is undersized and conditions aren't perfect. Most likely it will leak out the low-end and buzz rather than create a mild resonation to help the lowest frequencies. It will sound really bad if it buzzes badly enough to make your CD player skip on certain notes. I'll try without the port first but I worry about the sub not having any access at all to outside air, all fully sealed boxes I've seen (where the sub is mounted entirely inside the box I forget what this mounting style is called), have had vents to let it push some outside air around. The hole isn't to let out air. It is to set up a resonance at a low frequency (resonate like a large glass bottle does) where a sealed enclosure would begin to perform poorly or have too much excursion. Tuned port enclosures are common because they're louder than sealed enclosures. Also, a large sealed enclosure may cause overexcursion in the speaker because there's too little of an acoustic load. Adding a tuned port increases the acoustic load at the tuned frequency. The downside of a tuned port is that it can easily sound very bad when done wrong. A sealed enclosure has a smooth frequency roll-off where a tuned port enclosure has a very sharp drop-off below the tuned frequency. Below the tuned port frequency, the port is just a big air leak. Small enclosures are almost always best without a tuned port. They're inefficient but they at least produce some deep bass. A small enclosure with a tuned port will hum or buzz and produce no deep bass. You can find frequency charts online that compare the two enclosures. The only kind of port likely to help would be a long and fat pipe that adds to the box volume. A special speaker calculator is needed for ports that are large compared to the enclosure. I've seen them before online but don't remember where. It's probably more trouble than it's worth, especially when it comes to routing a giant port under the dash. Cool I'll do some googling and try to find it. Polyfill helps a sealed enclosure. BTW, I do hope you're talking about an inclosure installed inside the interior panels. The plastic panels alone won't hold much sound pressure, maybe only 35W average without breaking or hissing from air leaks. At least line it with fiberglass inside to stiffen it and form an airtight seal. I've got some thin MDF I was going to use, but fiberglass might be easier to deal with the curves. I hadn't thought about that thanks. |
#7
|
|||
|
|||
unusual custom sub enclosure question
Kevin McMurtrie wrote:
In article 3FFC3E2A.2070204@usefirstinitialandlastnameATerol s.com, Simon Juncal wrote: Kevin McMurtrie wrote: I wouldn't use a port at all. It's asking for trouble when the box is undersized and conditions aren't perfect. Most likely it will leak out the low-end and buzz rather than create a mild resonation to help the lowest frequencies. It will sound really bad if it buzzes badly enough to make your CD player skip on certain notes. I'll try without the port first but I worry about the sub not having any access at all to outside air, all fully sealed boxes I've seen (where the sub is mounted entirely inside the box I forget what this mounting style is called), have had vents to let it push some outside air around. The hole isn't to let out air. It is to set up a resonance at a low frequency (resonate like a large glass bottle does) where a sealed enclosure would begin to perform poorly or have too much excursion. Tuned port enclosures are common because they're louder than sealed enclosures. Also, a large sealed enclosure may cause overexcursion in the speaker because there's too little of an acoustic load. Adding a tuned port increases the acoustic load at the tuned frequency. The downside of a tuned port is that it can easily sound very bad when done wrong. A sealed enclosure has a smooth frequency roll-off where a tuned port enclosure has a very sharp drop-off below the tuned frequency. Below the tuned port frequency, the port is just a big air leak. Small enclosures are almost always best without a tuned port. They're inefficient but they at least produce some deep bass. A small enclosure with a tuned port will hum or buzz and produce no deep bass. Excellent explanation. I've got the sub temporarilly inside the console (which is a work in progress) with no port and I'm getting the idea that it will actually sound decent. It actually sounds pretty good just sitting free inside (not rattling on anything), which is obviously very inefficient. It thumps a lot harder mounted, once I get the walls reinforced with fiberglass, and fabricate a sealable top and polyfill it, it should thoeretically smooth out again right? -- Simon "I may be wrong, but I'm not uncertain." -- Robert A. Heinlein |
Reply |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
1994 Lexus es300 custom install | Car Audio | |||
sub location question | Car Audio | |||
Enclosure Size & Speaker Placement of Mid Range | Car Audio | |||
Repost: Reason 2.0 on a Celeron 2GHz laptop. | General | |||
Enclosure question | Car Audio |