First of all i have a 2004 regular cab f-150. I just purchased a JL Audio 300/4 and a JL 13w1v2 subwoofer. The subwoofer is installed behind the driver seat in a sealed box that is spec. size. I dont know how to get the sub to sound right. I have the stock AM/FM radio and i play my ipod through the itunes FM radio station and to be honest the sub sounds horrible sometimes. It distorts all the time. I think the problem has something to do with the filter freq. The crossover is set on LP, 12 db, and 1x and 55(Hz). Could someone please school me on this very confusing JL gear. Thanks!
Replies (19)
ShootuhMcBustaCap on 11/22/2006 14:42:17
Use of a four channel amp with a sub can make things difficult for you. That could be a problem. Your crossover is also set pretty low, try the 70-100 hz range. That will allow more frequencies into your sub, and higher fruquencies than 55 hz being blocked can affect the bas your shooting for.
How do you have your sub wired. Do you have your channels bridged, and one channel to each voice coil? I've never tried to wire a single sub to a four channel, I'm curious as to how this works.
I'm not sure of the wattages on your amp/sub combo is, but the amp is 75x4 correct? And were talking the sub is the W1? Im not so sure about JL equipment specs, but the W1 would be there entry level sub, If thats right, your probably overpowering the sub.
12 DB is a lot of bass boost on any amp. I gurantee if you crank that down between 3-6, It may not be as loud, but it'll sound way cleaner.
A stock head unit and a radio modulated Ipod isn't going to sound pretty no matter what speakers-amp-sub you have. Mp3's are compressed files, and the more compressed, the worse the sound quality. Exspecially if it's a song withoud a lot of crackling popping or hissing. These symptoms are common exspecially on internet downloaded files, and tracks ripped off scratched CD's.
Then your sending info through the radio. Here your limited by radio reception, and the FM sensitivity of your radio. static and other niose can enter here.
After then, your sending the amp's signal through either a high level input, or a line lever converter. These suck, as both have to "clean" the signal, whick is weak as it sits, and this causes distortion and low output.
I hate to say it, but poor equipment choice is probably the problem. Stock head units are taboo for great stereos, because of problems listed. If you had a stock nav unit or a BMW, it's kinda hard to just can it, but the stock AM/FM needs to go. I understand budget problems, they kill me, but it's gotta go.
A dedicated class D sub amp will work some wonders here. A 4 channel on a single sub sounds way dangerous, and your pulling way more current from your electrical system than is neccerary to power this sub.
Noise killing amp cables will definetly help. These aren't cheap, but they are awesome.
Check out a decent deck with MP3/WMA readibility, with at leats 4 volt amp preouts. Mp3 cd's rock I swear by them now. 20 hours on one disc with my computer's compression! I don't keep cd in my car anymore, I just burn a new cd once every two weeks and i'm on with it. Check out some units that have ipod interfaces too.
Any way, I hope I helped. a good head unit would definitely be the first thing to look at after playing with your amp. A good sub amp would be good too.
Shootuh McBustaCap
Victor on 11/22/2006 17:39:27
The JL sub 13w1v2 is a 200wrms sub... and a single 4 ohm voice coil..
and the amp is rated at 75wrms x 4 and 150wrms x 2 ( bridged mode 4 ohm stable ) and Fully-variable (50 Hz - 5 kHz), selectable-slope / mode (12 or 24 dB / octave, LP or HP) for each pair of channels
So this is a very flexible amp and would do perfectly fine with the sub.
All you have to do is use the rear 2 channels in the bridged mode to the sub... simple as that.
A good ported enclosure can assure some good boost to low frequency content.
Tweaking the amp with a proper crossover setting and gain settings, it should do just perfectly smooth......
Turn up the Xover knob a bit to 80Hz and a 12 db slope..... set the gains good, and use some bass boost ... and the ported enclosure would do the rest...
since its just a single amp you are using, no need to worry about the current draw cause all that amp can suck is a 38amp @ full power as per the JL specs... your stock charging system can easily support that...
think of changing your enclosure from the sealed to a ported..
the JL manual suggest a 1.5 cuft sealed and a 2.63 cuft ported enclosure tuned to 26Hz.... if you get a good ported enclosure nothing like it,, some real good lows...
regarding the FM... well it has its own pro's and con's , but this much would definitely make u feel the difference in bass.. ofcourse an aftermarket HU would help a lot...
ShootuhMcBustaCap on 11/22/2006 17:43:15
Even with the Fm modulated Ipod hook up to a stock H/U?
ShootuhMcBustaCap on 11/22/2006 17:49:28
my bad
ShootuhMcBustaCap on 11/22/2006 17:55:42
With the current draw, I'm thinking as whats required to power the sub, not how it's effecting the electrical system.
swez on 11/22/2006 18:05:13
Victor is pointing the way to best use this amp and that sub. Use only the rear channels on this amp, BRIDGED to power the sub. Use the front amp channels to power a decent set of full range speakers and you'll be OK.
Using a stock HU will limit your features, options and overall sound quality. Here, it would be a good investment to consider a nice Aftermarket HU that has more EQ options and RCA's for F,R & Sub amplification.
Pioneer Premier lines have I-Pod line in features that should dramatically improve performance and sound quality for your I-Pod and CD use. FM modulated devices are very inferior to hardwired AUX devices. They work, but nearly as well as hardwired systems.
The DEH-4800MP is a good fit and I-Pod ready AUX inputs too. It has some EQ features, (3 band Parametric w/ 6 preset EQ curves) but a very low price, if one is on a tight budget. Have a look:
http://www.crutchfield.com/S-2qKIRUg7aTb/cgi-bin/ProdView.asp?g=300&tab=detailed_info&i=130DEHP480#Tab
Swez
DaculabBall50 on 11/23/2006 23:09:06
Victor, About the ported box. I've heard they make a huge difference on the low base. But i have a regular cab truck. The sub is in an angled 1.5 cu ft box that i custom made. Can you make a ported angled box?
swez on 11/24/2006 01:31:39
Yes, ported boxes do make a big difference on subs that are made for ported enclosure designs. They are about 30-50% larger than sealed, but depending on the port tuning frequency used, that extra bump can be centered for deep bass (35 Hz) reinforcement or if one is shooting for high SPL, then more like 45-55 Hz., is used for tuning target.
NOTE: When using a ported enclosure, the sub needs to be protected with an infrasonic or subsonic filter, appropriate to the port tuning frequency.
To use a ported design here, JL recommends a 2.625 ft^3 enclosure, tuned at 26 Hz. The basic shape of your present box may be useful, if you can extend the overall width of the box w/o taking up too much space. A hybrid can also be used if needed. Say 2.25 ft^3, tuned to about 35 Hz. To save some space, one can use a pair of 4" round ports instead of the slotted port design noted by JL. (Same idea, just less port displacement is all)
Here's the JL link for that sub:
http://mobile.jlaudio.com/pdfs/8331.pdf
Swez
DaculabBall50 on 11/24/2006 11:16:46
Well i have plenty of room. The box is 23" long right now. I see that the port is in an L shape in the JL Spec Box. How can i do that with an angled box? Also how do you tune a box?
swez on 11/24/2006 12:56:10
Slotted ports make a lot of sense in very high powered SPL sub applications. (700 watts RMS and up) They allow plenty of air flow and keep port noise to a minimum at high SPL levels.
In this case, this sub is rated at a very modest 200 watts RMS. Here, round ports are more than adequate and are tunable based on enclosure size, (Vb), port diameter and port length. Single or multiple round ports can be used, depending on the diameter and length of porting needed.
How does a port work?
It's very similar to grabbing a 20 oz pop bottle and also a 2 liter bottle. When both are empty and we blow across the opening, we get a tone. The 20 oz container is smaller, so the pitch will be higher. The larger container is much larger in air volume, so we can expect a lower tone here. Port tuning uses the same general principles.
However, in accurate port tuning enclosures, we have to calculate airspace, the port diameter and port length to obtain the desired tuning frequency. We can help you with these calculations if you wish to try a new ported box that will fit in the space you have behind the seat.
What are the external measurements of the wedge box design you have now?
Height =
Depth 1 =
Depth 2 =
Width = 23.0 " (Right?)
Thickness of wood used = ???
Comments?
Swez
DaculabBall50 on 11/24/2006 13:45:22
Height- 16 3/4
Depth Top- 7 1/2
Depth Bottom- 11 1/4
Width- 24 1/2
Thickness of wood used- 3/4 MDF
The box can really only get wider. Also the sub takes up the entire room behind the drivers seat. But there is room between the back of the seat and the sub because of the angle of the box. Would the sub do better being behind the center seat with nothing in front of it because i have a bench seat with a fold down arm rest that can make a 3rd seat.
swez on 11/24/2006 14:09:30
After runing some numbers, the internal airspace of this enclosure is about 1.6 ft^3 as is. If we take sub displacement out, that nets about 1.5ft^3.
Locating the sub so it is just behind the center console, makes the most sense. There's more airspace between the woofer and any hard surface obstructions, in front of the cone. (reflections and sound damping are minimized this way.
As for porting, it would be good to port at the top of the wedge and fires up toward the roof of this truck. A single 4" port of the proper length is a good option. Or, using dual 4" ports will also work fine here. (The ports will be shorter this way)
Question: If you left all dimensions the same, but changed the overall width to 36.0 - 40.0", this would net 2.4 - 2.6ft^3. Now, what is the max width box you can fit back there? Also, what is your favorite type of music? (Rock, Rap, Hip-Hop, other?)
Depending on the max width your truck can handle, we can then run some additional numbers to determine the proper tuning ports for the new enclosure.
Comments?
Swez
DaculabBall50 on 11/24/2006 14:52:29
Well it can go 16 inches or so more. Easily 36-40 inches. I listen to mostly Rap. I love low bass.
swez on 11/24/2006 21:32:42
Good! That will allow you to go ported and not change any other dimensions except the width.
If you used an external width dimension of 38" and all other dimensions are the same, that gives a nice Vb of ~2.5ft^3. For porting and tuning, use one 4" round port, 12.0" long and loaded at the top of your box. (passenger side is good) The tuning frequency here, is about 30 Hz. (Perfect for Rap and other deep low bass music)
Parts List:
Port flange and tube kit:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=268-332
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=268-338
Yes, you can easily make your own port with PVC pipe as well. It's a lot cheaper and you can buy them at any Home Depot, Lowe's etc.
Comments?
Swez
DaculabBall50 on 11/24/2006 23:44:41
ok. I'm kind of confused. The box would have to behind my seat and extend to the beginning of the passenger seat (because my amp is mounted on the floor behind the passenger seat) leaving the sub to be facing the front of the truck behind my arm rest. And the port just goes in the top of the box anywhere i want it go? Close to the Sub? Far? Also how do you tune a port?
Thanks for all the help. I really appreciate it. I was lost before i found all of you helpfull people. I moved the filter freq to 80 hz and i moved the sealed box to in between the seats so it had room to breathe and its made a big difference but i cannot wait until i make my new box. Even more BASS!
DaculabBall50 on 11/24/2006 23:48:45
One more question. What where you saying about a subsonic filter with a ported box?
swez on 11/25/2006 11:55:43
If you need the extra floor space where the amp is now installed, move it to the vertical rear wall, with the heat sinks facing upward. The amp is less than 3 inches in height, and can be hidden behind the rear panel covering.
As for port location, it would be good to mount the port on top the box and at the passenger end of the box. This takes full advantage of your wide wedge design.
The port is tuned using 3 main factors:
1. Airspace inside the box (Vb)
2. Diameter of the port (4")
3. Length of the port (12")
You can buy a low cost infrasonic filter module that will block harmful lows to your sub. They are RCA type barrel filters and fit inline between the HU outputs and amp inputs: Harrison Labs FMods
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=266-248
These come in pairs and designed to block very low frequencies, (infrasonics, below 30 Hz.) but pass bass frequencies your sub can handle properly. (30 Hz. and up)
The male part of these modules, plug into your amp input section. Your RCA's from the HU, plug into the female section of the module.
Got all that?
Swez
DaculabBall50 on 11/26/2006 08:50:14
Yes the only thing that is still a little unclear is the port location. The box is only going to span the width of one seat and the center arm rest. If i left the amp on the ground behind the passenger seat the box would have to go sit behind the driver seat and the middle seat (where the fold down arm rest is). I was planning on putting the sub behind the arm rest instead of behind the seat because it would give the sub more breathing room. That would mean the rest of the box would be behind my seat. If i used this configuartion where would the port go. On top of my box behind my seat?
But i like the idea of putting the amp on the rear wall of my truck. For christmas i'm getting dynamat for both doors and the rear wall. I could put the amp back there after the dynamat went up. Would the amp get sufficient cooling behind the plastic wall? I will be using the full 300 watts after christmas because i'm also getting components for christmas.
Also would putting DynaXord in my new subbox behind the sub and behind my new speakers be beneficial to me?
http://www.dynamat.com/products_car_audio_dynaxorb.html
Also about the port tuning thing. Once you know those three things you listed above you used a formula to find out the tuning of the port right? I thought you had to use a machine of some sort to tune them.
Thanks so much for all your help! You have been such a great help in fixing my car audio. The sub is already sounding 100x better because it isn't behind my seat anymore. I can't wait until i make my new box.
swez on 11/26/2006 15:26:51
We already have a good idea about the physical dimensions of the new ported box right? Yes! The trick here, is to locate the sub in the spot where it has the most room to breath. (Behind the center arm rest)
The sub "does not" have to be located in the center of a given wedge design. It can be moved to one side of the box and the port is located on the opposite side of said box.
Dynamat will help deaden your doors and rear cabin panel very well. If you want to mount your amp(s) on the back wall, it is best to cut out a window in the plastic/fiber cover panel to allow the amp to cool properly. This cutout needs to be large enough to not only cool the amp, but also allow access to the amp for adjustments and removal too.
"DynaXorb" is a good idea. But we can get the same affect using low cost polyfil or other sound absorbant materials. The main idea here, is to absorb some of the rear wave cone energy so it does not reflect back into the rear of the cone. I have even used discarged carpeting or padding, (1.0 - 1.5" thick sheets) to net the same affect and it cost nothing. A sheet of Plush pile or Burber carpeting, works very well this way. (Just make sure it is clean of dirt, sand and other debris, before installing it.
Port tuning is basically mathmatics and physics. Yes, you can measure/verify the results with expensive test equipment. But if one gets the math right, the results are very predicatable.
Am glad you have learned some new things. See how something as simple as moving the sub to a different location can really change the overall performance? Some things are really just that simple. There will be even more performance changes, once you install your ported sub. The low bass will really come to life due to porting. (Just wait and see)
Swez ;-)
Replies (19)
ShootuhMcBustaCap on 11/22/2006 14:42:17
Use of a four channel amp with a sub can make things difficult for you. That could be a problem. Your crossover is also set pretty low, try the 70-100 hz range. That will allow more frequencies into your sub, and higher fruquencies than 55 hz being blocked can affect the bas your shooting for.
How do you have your sub wired. Do you have your channels bridged, and one channel to each voice coil? I've never tried to wire a single sub to a four channel, I'm curious as to how this works.
I'm not sure of the wattages on your amp/sub combo is, but the amp is 75x4 correct? And were talking the sub is the W1? Im not so sure about JL equipment specs, but the W1 would be there entry level sub, If thats right, your probably overpowering the sub.
12 DB is a lot of bass boost on any amp. I gurantee if you crank that down between 3-6, It may not be as loud, but it'll sound way cleaner.
A stock head unit and a radio modulated Ipod isn't going to sound pretty no matter what speakers-amp-sub you have. Mp3's are compressed files, and the more compressed, the worse the sound quality. Exspecially if it's a song withoud a lot of crackling popping or hissing. These symptoms are common exspecially on internet downloaded files, and tracks ripped off scratched CD's.
Then your sending info through the radio. Here your limited by radio reception, and the FM sensitivity of your radio. static and other niose can enter here.
After then, your sending the amp's signal through either a high level input, or a line lever converter. These suck, as both have to "clean" the signal, whick is weak as it sits, and this causes distortion and low output.
I hate to say it, but poor equipment choice is probably the problem. Stock head units are taboo for great stereos, because of problems listed. If you had a stock nav unit or a BMW, it's kinda hard to just can it, but the stock AM/FM needs to go. I understand budget problems, they kill me, but it's gotta go.
A dedicated class D sub amp will work some wonders here. A 4 channel on a single sub sounds way dangerous, and your pulling way more current from your electrical system than is neccerary to power this sub.
Noise killing amp cables will definetly help. These aren't cheap, but they are awesome.
Check out a decent deck with MP3/WMA readibility, with at leats 4 volt amp preouts. Mp3 cd's rock I swear by them now. 20 hours on one disc with my computer's compression! I don't keep cd in my car anymore, I just burn a new cd once every two weeks and i'm on with it. Check out some units that have ipod interfaces too.
Any way, I hope I helped. a good head unit would definitely be the first thing to look at after playing with your amp. A good sub amp would be good too.
Shootuh McBustaCap
Victor on 11/22/2006 17:39:27
The JL sub 13w1v2 is a 200wrms sub... and a single 4 ohm voice coil..
and the amp is rated at 75wrms x 4 and 150wrms x 2 ( bridged mode 4 ohm stable ) and Fully-variable (50 Hz - 5 kHz), selectable-slope / mode (12 or 24 dB / octave, LP or HP) for each pair of channels
So this is a very flexible amp and would do perfectly fine with the sub.
All you have to do is use the rear 2 channels in the bridged mode to the sub... simple as that.
A good ported enclosure can assure some good boost to low frequency content.
Tweaking the amp with a proper crossover setting and gain settings, it should do just perfectly smooth......
Turn up the Xover knob a bit to 80Hz and a 12 db slope..... set the gains good, and use some bass boost ... and the ported enclosure would do the rest...
since its just a single amp you are using, no need to worry about the current draw cause all that amp can suck is a 38amp @ full power as per the JL specs... your stock charging system can easily support that...
think of changing your enclosure from the sealed to a ported..
the JL manual suggest a 1.5 cuft sealed and a 2.63 cuft ported enclosure tuned to 26Hz.... if you get a good ported enclosure nothing like it,, some real good lows...
regarding the FM... well it has its own pro's and con's , but this much would definitely make u feel the difference in bass.. ofcourse an aftermarket HU would help a lot...
ShootuhMcBustaCap on 11/22/2006 17:43:15
Even with the Fm modulated Ipod hook up to a stock H/U?
ShootuhMcBustaCap on 11/22/2006 17:49:28
my bad
ShootuhMcBustaCap on 11/22/2006 17:55:42
With the current draw, I'm thinking as whats required to power the sub, not how it's effecting the electrical system.
swez on 11/22/2006 18:05:13
Victor is pointing the way to best use this amp and that sub. Use only the rear channels on this amp, BRIDGED to power the sub. Use the front amp channels to power a decent set of full range speakers and you'll be OK.
Using a stock HU will limit your features, options and overall sound quality. Here, it would be a good investment to consider a nice Aftermarket HU that has more EQ options and RCA's for F,R & Sub amplification.
Pioneer Premier lines have I-Pod line in features that should dramatically improve performance and sound quality for your I-Pod and CD use. FM modulated devices are very inferior to hardwired AUX devices. They work, but nearly as well as hardwired systems.
The DEH-4800MP is a good fit and I-Pod ready AUX inputs too. It has some EQ features, (3 band Parametric w/ 6 preset EQ curves) but a very low price, if one is on a tight budget. Have a look:
http://www.crutchfield.com/S-2qKIRUg7aTb/cgi-bin/ProdView.asp?g=300&tab=detailed_info&i=130DEHP480#Tab
Swez
DaculabBall50 on 11/23/2006 23:09:06
Victor, About the ported box. I've heard they make a huge difference on the low base. But i have a regular cab truck. The sub is in an angled 1.5 cu ft box that i custom made. Can you make a ported angled box?
swez on 11/24/2006 01:31:39
Yes, ported boxes do make a big difference on subs that are made for ported enclosure designs. They are about 30-50% larger than sealed, but depending on the port tuning frequency used, that extra bump can be centered for deep bass (35 Hz) reinforcement or if one is shooting for high SPL, then more like 45-55 Hz., is used for tuning target.
NOTE: When using a ported enclosure, the sub needs to be protected with an infrasonic or subsonic filter, appropriate to the port tuning frequency.
To use a ported design here, JL recommends a 2.625 ft^3 enclosure, tuned at 26 Hz. The basic shape of your present box may be useful, if you can extend the overall width of the box w/o taking up too much space. A hybrid can also be used if needed. Say 2.25 ft^3, tuned to about 35 Hz. To save some space, one can use a pair of 4" round ports instead of the slotted port design noted by JL. (Same idea, just less port displacement is all)
Here's the JL link for that sub:
http://mobile.jlaudio.com/pdfs/8331.pdf
Swez
DaculabBall50 on 11/24/2006 11:16:46
Well i have plenty of room. The box is 23" long right now. I see that the port is in an L shape in the JL Spec Box. How can i do that with an angled box? Also how do you tune a box?
swez on 11/24/2006 12:56:10
Slotted ports make a lot of sense in very high powered SPL sub applications. (700 watts RMS and up) They allow plenty of air flow and keep port noise to a minimum at high SPL levels.
In this case, this sub is rated at a very modest 200 watts RMS. Here, round ports are more than adequate and are tunable based on enclosure size, (Vb), port diameter and port length. Single or multiple round ports can be used, depending on the diameter and length of porting needed.
How does a port work?
It's very similar to grabbing a 20 oz pop bottle and also a 2 liter bottle. When both are empty and we blow across the opening, we get a tone. The 20 oz container is smaller, so the pitch will be higher. The larger container is much larger in air volume, so we can expect a lower tone here. Port tuning uses the same general principles.
However, in accurate port tuning enclosures, we have to calculate airspace, the port diameter and port length to obtain the desired tuning frequency. We can help you with these calculations if you wish to try a new ported box that will fit in the space you have behind the seat.
What are the external measurements of the wedge box design you have now?
Height =
Depth 1 =
Depth 2 =
Width = 23.0 " (Right?)
Thickness of wood used = ???
Comments?
Swez
DaculabBall50 on 11/24/2006 13:45:22
Height- 16 3/4
Depth Top- 7 1/2
Depth Bottom- 11 1/4
Width- 24 1/2
Thickness of wood used- 3/4 MDF
The box can really only get wider. Also the sub takes up the entire room behind the drivers seat. But there is room between the back of the seat and the sub because of the angle of the box. Would the sub do better being behind the center seat with nothing in front of it because i have a bench seat with a fold down arm rest that can make a 3rd seat.
swez on 11/24/2006 14:09:30
After runing some numbers, the internal airspace of this enclosure is about 1.6 ft^3 as is. If we take sub displacement out, that nets about 1.5ft^3.
Locating the sub so it is just behind the center console, makes the most sense. There's more airspace between the woofer and any hard surface obstructions, in front of the cone. (reflections and sound damping are minimized this way.
As for porting, it would be good to port at the top of the wedge and fires up toward the roof of this truck. A single 4" port of the proper length is a good option. Or, using dual 4" ports will also work fine here. (The ports will be shorter this way)
Question: If you left all dimensions the same, but changed the overall width to 36.0 - 40.0", this would net 2.4 - 2.6ft^3. Now, what is the max width box you can fit back there? Also, what is your favorite type of music? (Rock, Rap, Hip-Hop, other?)
Depending on the max width your truck can handle, we can then run some additional numbers to determine the proper tuning ports for the new enclosure.
Comments?
Swez
DaculabBall50 on 11/24/2006 14:52:29
Well it can go 16 inches or so more. Easily 36-40 inches. I listen to mostly Rap. I love low bass.
swez on 11/24/2006 21:32:42
Good! That will allow you to go ported and not change any other dimensions except the width.
If you used an external width dimension of 38" and all other dimensions are the same, that gives a nice Vb of ~2.5ft^3. For porting and tuning, use one 4" round port, 12.0" long and loaded at the top of your box. (passenger side is good) The tuning frequency here, is about 30 Hz. (Perfect for Rap and other deep low bass music)
Parts List:
Port flange and tube kit:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=268-332
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=268-338
Yes, you can easily make your own port with PVC pipe as well. It's a lot cheaper and you can buy them at any Home Depot, Lowe's etc.
Comments?
Swez
DaculabBall50 on 11/24/2006 23:44:41
ok. I'm kind of confused. The box would have to behind my seat and extend to the beginning of the passenger seat (because my amp is mounted on the floor behind the passenger seat) leaving the sub to be facing the front of the truck behind my arm rest. And the port just goes in the top of the box anywhere i want it go? Close to the Sub? Far? Also how do you tune a port?
Thanks for all the help. I really appreciate it. I was lost before i found all of you helpfull people. I moved the filter freq to 80 hz and i moved the sealed box to in between the seats so it had room to breathe and its made a big difference but i cannot wait until i make my new box. Even more BASS!
DaculabBall50 on 11/24/2006 23:48:45
One more question. What where you saying about a subsonic filter with a ported box?
swez on 11/25/2006 11:55:43
If you need the extra floor space where the amp is now installed, move it to the vertical rear wall, with the heat sinks facing upward. The amp is less than 3 inches in height, and can be hidden behind the rear panel covering.
As for port location, it would be good to mount the port on top the box and at the passenger end of the box. This takes full advantage of your wide wedge design.
The port is tuned using 3 main factors:
1. Airspace inside the box (Vb)
2. Diameter of the port (4")
3. Length of the port (12")
You can buy a low cost infrasonic filter module that will block harmful lows to your sub. They are RCA type barrel filters and fit inline between the HU outputs and amp inputs: Harrison Labs FMods
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=266-248
These come in pairs and designed to block very low frequencies, (infrasonics, below 30 Hz.) but pass bass frequencies your sub can handle properly. (30 Hz. and up)
The male part of these modules, plug into your amp input section. Your RCA's from the HU, plug into the female section of the module.
Got all that?
Swez
DaculabBall50 on 11/26/2006 08:50:14
Yes the only thing that is still a little unclear is the port location. The box is only going to span the width of one seat and the center arm rest. If i left the amp on the ground behind the passenger seat the box would have to go sit behind the driver seat and the middle seat (where the fold down arm rest is). I was planning on putting the sub behind the arm rest instead of behind the seat because it would give the sub more breathing room. That would mean the rest of the box would be behind my seat. If i used this configuartion where would the port go. On top of my box behind my seat?
But i like the idea of putting the amp on the rear wall of my truck. For christmas i'm getting dynamat for both doors and the rear wall. I could put the amp back there after the dynamat went up. Would the amp get sufficient cooling behind the plastic wall? I will be using the full 300 watts after christmas because i'm also getting components for christmas.
Also would putting DynaXord in my new subbox behind the sub and behind my new speakers be beneficial to me?
http://www.dynamat.com/products_car_audio_dynaxorb.html
Also about the port tuning thing. Once you know those three things you listed above you used a formula to find out the tuning of the port right? I thought you had to use a machine of some sort to tune them.
Thanks so much for all your help! You have been such a great help in fixing my car audio. The sub is already sounding 100x better because it isn't behind my seat anymore. I can't wait until i make my new box.
swez on 11/26/2006 15:26:51
We already have a good idea about the physical dimensions of the new ported box right? Yes! The trick here, is to locate the sub in the spot where it has the most room to breath. (Behind the center arm rest)
The sub "does not" have to be located in the center of a given wedge design. It can be moved to one side of the box and the port is located on the opposite side of said box.
Dynamat will help deaden your doors and rear cabin panel very well. If you want to mount your amp(s) on the back wall, it is best to cut out a window in the plastic/fiber cover panel to allow the amp to cool properly. This cutout needs to be large enough to not only cool the amp, but also allow access to the amp for adjustments and removal too.
"DynaXorb" is a good idea. But we can get the same affect using low cost polyfil or other sound absorbant materials. The main idea here, is to absorb some of the rear wave cone energy so it does not reflect back into the rear of the cone. I have even used discarged carpeting or padding, (1.0 - 1.5" thick sheets) to net the same affect and it cost nothing. A sheet of Plush pile or Burber carpeting, works very well this way. (Just make sure it is clean of dirt, sand and other debris, before installing it.
Port tuning is basically mathmatics and physics. Yes, you can measure/verify the results with expensive test equipment. But if one gets the math right, the results are very predicatable.
Am glad you have learned some new things. See how something as simple as moving the sub to a different location can really change the overall performance? Some things are really just that simple. There will be even more performance changes, once you install your ported sub. The low bass will really come to life due to porting. (Just wait and see)
Swez ;-)
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