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rickymac21
08-29-2013, 12:30 AM
Well after four years of no bass I'm returning to the playing fields. All the information you may need is listed below.

I already have ideas for designing this box. But my biggest pet peeve when it comes to trunk installs is trunk rattle. Plus I feel like you lose db's by having that issue. So my idea was to do as most people do and seal the subs/box from the trunk. Only problem is my seats don't fold down so I can't really build a successful half wall... So here's what I came up with.

Exterior Dimensions:
30"W x 14" H x 26" D

And using 1" thick MDF the interior dimensions would be...
28"W x 12.25" H (bottom plate will only be 3/4") x 24" D

This should give me roughly 4.76 cubes before displacement of sub/aeroport and bracing. Figured I'll end up with around 4.25 cubes after displacement but I haven't accurately calculated that. The port will most likely be 6" aero which will give me about 6.6 sq in per cubic ft (28.26 sq in total). A little low but I'd rather have 1 6" and be there than 1 8" and be at 50 sq in. Could do 3 4" but I think 1 port would be more efficient for air flow.....

Anyways. The sub will be on top of the box firing up in the trunk. The port will be partially external firing up like the sub. This is because I'd like to cut a hole in the rear dash and have the port "exhausting" or firing into the passenger/cabin area directly....

Now the tricky part would be stopping the trunk rattle... I will more than likely have seal it off like most trunk walls, only from the reverse side of the box, if that makes sense... Basically where the trunk lid (the part that actually pops up) pivits, I will have to build a wall straight down on top and around the box. taking this wall all the way to the sides, top, bottom of the trunk (right before the trunk lid opening) should hopefully create a strong enough barrier to prevent any lost db's.

It's rather hard to explain in words so I am sorry... But if you were creative enough to paint a mental picture of what I had in mind, what are your opinions on this? Do I have any other options for max output.

Vehicle : 2002 BMW 325i

Location in the vehicle: Trunk

Space available (Length x Width x Height): 27" L x 35" W x 17" H

Subwoofer make and model: American Bass xfl 15

Subwoofer Size: 15"

Number of Subwoofers: 1

Type of Port (Kerfed, Slot, Aero, etc.): Aero

SPL or Everyday Music?: Daily Driver

Tuning Freq (Hz): 32-36

Amplifier: Hifonics brx2400

Car electrical information:

-Stock 120a alt
-Big 3 w/0 gauge will be done
-Stock battery with a secondary battery.

Side Show
08-29-2013, 12:59 AM
does the back seat/seats fold down?

rickymac21
08-29-2013, 01:45 AM
does the back seat/seats fold down?

No. Otherwise I would just do a 'trunk wall' like most people.

rickymac21
08-29-2013, 08:09 AM
Morning bump. . . Just anxious to hear some opinions

NASTY08IMPALA
08-29-2013, 10:28 AM
Morning bump. . . Just anxious to hear some opinions

Do u have the fold down rear ski hole in the center of seats like some bimmers? if so port it through there or.the rear deck or results will be diminished

bmk6795
08-29-2013, 10:42 AM
is it just me or does 6.6 sq in of port area per cube seem really small?

rickymac21
08-29-2013, 12:47 PM
Do u have the fold down rear ski hole in the center of seats like some bimmers? if so port it through there or.the rear deck or results will be diminished

I have a fold down arm rest, but no ski hole. It's just metal. I guess I could cut a hole there but I think through the rear deck/dash would look better/ less noticeable.

rickymac21
08-29-2013, 12:50 PM
is it just me or does 6.6 sq in of port area per cube seem really small?

Yea it is. But like I said I'd rather have 1 6" port than 3 4". If I can get/ make 7" that would be perfect. I don't think they make 7" PVC

Buck
08-29-2013, 12:52 PM
It's going to rattle no matter what. It's pressurization, it's non-directional (omnidirectional) so firing in certain directions in the trunk isn't really going to do much, all of your bass originates in the trunk and therefore pressurizes it no matter of the direction. I would do sub up and port rear passenger side.

---------- Post added at 10:51 AM ---------- Previous post was at 10:51 AM ----------

Loading off the rear of the trunk is better IMO.

---------- Post added at 10:52 AM ---------- Previous post was at 10:51 AM ----------

6" aero and 4.25 cubes will work well, no need for 1" mdf. Use .75" and gain airspace.

rickymac21
08-29-2013, 02:49 PM
It's going to rattle no matter what. It's pressurization, it's non-directional (omnidirectional) so firing in certain directions in the trunk isn't really going to do much, all of your bass originates in the trunk and therefore pressurizes it no matter of the direction. I would do sub up and port rear passenger side.

---------- Post added at 10:51 AM ---------- Previous post was at 10:51 AM ----------


Loading off the rear of the trunk is better IMO.

---------- Post added at 10:52 AM ---------- Previous post was at 10:51 AM ----------

6" aero and 4.25 cubes will work well, no need for 1" mdf. Use .75" and gain airspace.


Well I understand the pressurization is originating from the trunk in a normal trunk install. But let me say this.
Forget everything I said before.
If someone were to build a sturdy wall (no box yet, just a wall) right at the trunk lid trim/opening. This wall would stretch from the floor-ceiling and side to side. Sealing the edges with spray foam or whatever other kind of sealant. So basically this would create a second trunk space that isn't exposed to the trunk lid.

Now if you put a sub within the sealed wall area of te trunk it would have to reduce trunk rattle and increase reverberations due to a sturdy wall to reflect off of. Plus if the port is firing air directly into the cabin it would help direct the sound right? I just feel the wall will reduce the rattle and in turn increase pressure/db's.

09civic
08-29-2013, 02:54 PM
No. Otherwise I would just do a 'trunk wall' like most people.

Rarely is it louder firing into the cabin vs. firing towards the trunk.

rickymac21
08-29-2013, 03:05 PM
Rarely is it louder firing into the cabin vs. firing towards the trunk.

Your the second one to say this. So maybe my theory is wrong. If firing towards the rear is just as loud I might as well save me the trouble of cutting holes in my rear dash.

So sub up port back then?

97maxima
08-29-2013, 03:07 PM
Rarely is it louder firing into the cabin vs. firing towards the trunk.
Too many variables, this statement is pretty far from the truth.

1 6in port is not enough for that sub, id run 2 6in. 3.25-4 cubes. But with the power you running id stay around 3.5 with running near double the rms. Those coils have their limits

rickymac21
08-29-2013, 03:27 PM
Too many variables, this statement is pretty far from the truth.

1 6in port is not enough for that sub, id run 2 6in. 3.25-4 cubes. But with the power you running id stay around 3.5 with running near double the rms. Those coils have their limits

2 6" ports for 4 cubes is almost double the average 8 sq in per cubic ft. But as far as the power issue, I've been told the Cfl's can handle 1800w Rms all day. So why couldn't I just wire it to 1 ohm and set the gain lower on the amp? This would help prevent clipping as well.

09civic
08-29-2013, 03:27 PM
Your the second one to say this. So maybe my theory is wrong. If firing towards the rear is just as loud I might as well save me the trouble of cutting holes in my rear dash.

So sub up port back then?

Port firing into the cabin, sub back.

Buck
08-29-2013, 03:31 PM
Too many variables, this statement is pretty far from the truth.

1 6in port is not enough for that sub, id run 2 6in. 3.25-4 cubes. But with the power you running id stay around 3.5 with running near double the rms. Those coils have their limits

1 6" port will work with a XFL. 2 6" is going to be unreasonably long.

Buck
08-29-2013, 03:33 PM
But it doesn't need that much power, lol.

rickymac21
08-29-2013, 03:39 PM
Port firing into the cabin, sub back.


Rarely is it louder firing into the cabin vs. firing towards the trunk.


Doesn't this contradict itself ? If it's not any louder why would I waste the time cutting a hole in my rear deck/dash?

09civic
08-29-2013, 03:59 PM
Doesn't this contradict itself ? If it's not any louder why would I waste the time cutting a hole in my rear deck/dash?

I meant port firing towards the glass upwards.

You were going to cut through the back deck, correct?

Imtjnotu
08-29-2013, 04:06 PM
are there no speakers in the rear deck...if so remove them that is ur best bet....face back into the truck it will be louder end of story

rickymac21
08-29-2013, 04:18 PM
I meant port firing towards the glass upwards.

You were going to cut through the back deck, correct?

Yes. Originally I wanted have the sub facing up and the port facing up. With the port extending out of the box and going through the rear deck so it's firing into the back window.

97maxima
08-29-2013, 04:29 PM
2 6" ports for 4 cubes is almost double the average 8 sq in per cubic ft. But as far as the power issue, I've been told the Cfl's can handle 1800w Rms all day. So why couldn't I just wire it to 1 ohm and set the gain lower on the amp? This would help prevent clipping as well.

trust me its avg for a sub like the xfl is 11-15 with a round port slot you could go 16 to 18. They are good for a clean 1500, ive ran about 5k to a pair before but you could not go hard on them for too long. you will def want the amp set cleanly

97maxima
08-29-2013, 04:31 PM
1 6" port will work with a XFL. 2 6" is going to be unreasonably long.

1 isnt enough, if length is a issue maybe 1 larger port would be better

09civic
08-29-2013, 04:32 PM
trust me its avg for a sub like the xfl is 11-15 with a round port slot you could go 16 to 18. They are good for a clean 1500, ive ran about 5k to a pair before but you could not go hard on them for too long. you will def want the amp set cleanly

No point going that big with port area unless you're chasing numbers.

97maxima
08-29-2013, 04:40 PM
Not true, ive had huge ports with a flat response within a few tenths. Big box, lottsa power, and tiny port dont make for a good build. Id run a sub with a more compliant suspension. XFLs are very stiff. Its like getting a mustang gt but not shifting out of 2nd gear

rickymac21
08-29-2013, 05:14 PM
Well I just made a little discovery. Apparently even though my car doesnt come stock with drop down seats or a ski hole, it does come pre-fabricated to install.. It's really just a just a punch-out ordeal. Strange, but now I have a connection from the trunk to the cabin without using any tools..

Now I just need to know what's the best sub/port placement to make the most of it.

http://i1272.photobucket.com/albums/y400/rwm41991/punchout4_zps10374c75.jpg (http://s1272.photobucket.com/user/rwm41991/media/punchout4_zps10374c75.jpg.html)
http://i1272.photobucket.com/albums/y400/rwm41991/punchout3_zpsa3fcae39.jpg (http://s1272.photobucket.com/user/rwm41991/media/punchout3_zpsa3fcae39.jpg.html)
http://i1272.photobucket.com/albums/y400/rwm41991/Punchout1_zps04911bf9.jpg (http://s1272.photobucket.com/user/rwm41991/media/Punchout1_zps04911bf9.jpg.html)
http://i1272.photobucket.com/albums/y400/rwm41991/punchout2_zps8dba147f.jpg (http://s1272.photobucket.com/user/rwm41991/media/punchout2_zps8dba147f.jpg.html)

rickymac21
08-29-2013, 05:20 PM
Not true, ive had huge ports with a flat response within a few tenths. Big box, lottsa power, and tiny port dont make for a good build. Id run a sub with a more compliant suspension. XFLs are very stiff. Its like getting a mustang gt but not shifting out of 2nd gear

wouldn't a smaller port be better than a larger port in a big box? If the port and box were big it would create a lack of resistance resistance for the sub and it would eventually bottom out? regardless, I feel 4.25 cu ft isn't on the large side anyways. Seems just right. And if I did want more port area like you say I'd feel more comfortable with 1 8" port rather than 2 6"... 6"sq in less, not much but better I feel like. Plus it would be more efficient than 2 ports as far as air flow....

But with the newly discovered ski hole, what would the best recommended box design be now as far as sub and port direction/placement....

97maxima
08-29-2013, 05:28 PM
wouldn't a smaller port be better than a larger port in a big box? If the port and box were big it would create a lack of resistance resistance for the sub and it would eventually bottom out? regardless, I feel 4.25 cu ft isn't on the large side anyways. Seems just right. And if I did want more port area like you say I'd feel more comfortable with 1 8" port rather than 2 6"... 6"sq in less, not much but better I feel like. Plus it would be more efficient than 2 ports as far as air flow....

But with the newly discovered ski hole, what would the best recommended box design be now as far as sub and port direction/placement....

To small a port and you end up with a sub that thinks its in a leaky sealed box. that suspension will keep the coil in check unless you play it hard under tuning. for that power 4.25 is a tad big wont have as much cone control.Which would be ok if your wanting to get that sub loud off less power and a more efficient enclosure. You could use a "8in" concrete form from lowes or home depot and fire it thru the ski hole into the cabin. sub up or to the rear.

rickymac21
08-29-2013, 05:40 PM
To small a port and you end up with a sub that thinks its in a leaky sealed box. that suspension will keep the coil in check unless you play it hard under tuning. for that power 4.25 is a tad big wont have as much cone control.Which would be ok if your wanting to get that sub loud off less power and a more efficient enclosure. You could use a "8in" concrete form from lowes or home depot and fire it thru the ski hole into the cabin. sub up or to the rear.

Have you ran the xfl 15? If so please explain to me what your box was like.. cubes? port area? tuning?

I would imagine with my stock 120a alternator and nothing more than 2 batteries and the big 3 i'll be fine on electrical... But I seriously doubt that the BRX2400 will really do 2400w rms at 1 ohm. I bet it's more like 1800 @ 12v. . . Which is what i'll be running on most likely (havent checked my cars voltage)... But even if the amp does put out 2000rms @ 1ohm why can't I just set the gain down on the amp to reduce the power?

I guess my other option would be to just buy the D4 ohm xfl and wire it to 2 ohms, but I don't want to do that because I'd have to turn the gain up on the amp and I don't want to risk clipping the amp or sub...

rickymac21
08-29-2013, 05:42 PM
How about this. ..

4.25 cubic ft box
8" aero port tuned to 34 hz
Sub wired to 1ohm
Amp gain set to 75-80%
Sub firing up and port firing foward into cabin (through ski hole)

?????????????

ancorp
08-29-2013, 06:17 PM
The gain is not a volume knob. Setting it to 75% wont give you 75% power. It's to match the head units output. With some head units you could get full power out of the amp at the gain at 25% if not lower.

The box sounds great to me. But if you stick that huge port into the ski pass, there won't be much area left for the rest of the sound to come through, and you will mostly get notes near the port tuning. I suggest you still open up your rear deck if you can.

Or you could build a 4th order box where everything comes out of the port, but I doubt you can fit a 4th order for a 15". You'd need at least 6 cubes. I would consider doing two XFL 10s in a 4th order in that vehicle with a rectangular port that fits the maximum size of the ski pass. Then you will have no trunk rattle at all, and the two coils will take the 2400w without a sweat. I'd start with building 1.5 cubes sealed, 3 cubes ported at 45-50hz or so, but people with actual 4th order XFL experience can chime in.

rickymac21
08-29-2013, 07:59 PM
The gain is not a volume knob. Setting it to 75% wont give you 75% power. It's to match the head units output. With some head units you could get full power out of the amp at the gain at 25% if not lower.

The box sounds great to me. But if you stick that huge port into the ski pass, there won't be much area left for the rest of the sound to come through, and you will mostly get notes near the port tuning. I suggest you still open up your rear deck if you can.

Or you could build a 4th order box where everything comes out of the port, but I doubt you can fit a 4th order for a 15". You'd need at least 6 cubes. I would consider doing two XFL 10s in a 4th order in that vehicle with a rectangular port that fits the maximum size of the ski pass. Then you will have no trunk rattle at all, and the two coils will take the 2400w without a sweat. I'd start with building 1.5 cubes sealed, 3 cubes ported at 45-50hz or so, but people with actual 4th order XFL experience can chime in.

Thanks for the heads up.. I'm not sure how I never knew this. Ignorance I guess. But I just did some reading and gave myself a quick lesson on the gain....

But if my amp is rated at 1600w rms at 2 ohms that would that be under-powering the XFL ? I was told 1800w rms is good for the sub so 1600 isn't much lower...

As for the making a 4th order box, I'm not opposed but from what I understand those usually only play well through a short range.??? I've never built one though so it would be fun to try, especially if you say it'll reduce trunk rattle.

bbeljefe
08-29-2013, 08:39 PM
2 6" ports for 4 cubes is almost double the average 8 sq in per cubic ft. But as far as the power issue, I've been told the Cfl's can handle 1800w Rms all day. So why couldn't I just wire it to 1 ohm and set the gain lower on the amp? This would help prevent clipping as well.

For high powered subs the average is 16 inē per cubic foot. I would keep the box small and use a square or slot port... that way you can get the size you need and you can easily configure it so that it fires through the package tray if that's what you want to do.

97maxima
08-29-2013, 09:14 PM
Have you ran the xfl 15? If so please explain to me what your box was like.. cubes? port area? tuning?

I would imagine with my stock 120a alternator and nothing more than 2 batteries and the big 3 i'll be fine on electrical... But I seriously doubt that the BRX2400 will really do 2400w rms at 1 ohm. I bet it's more like 1800 @ 12v. . . Which is what i'll be running on most likely (havent checked my cars voltage)... But even if the amp does put out 2000rms @ 1ohm why can't I just set the gain down on the amp to reduce the power?

I guess my other option would be to just buy the D4 ohm xfl and wire it to 2 ohms, but I don't want to do that because I'd have to turn the gain up on the amp and I don't want to risk clipping the amp or sub...


How about this. ..

4.25 cubic ft box
8" aero port tuned to 34 hz
Sub wired to 1ohm
Amp gain set to 75-80%
Sub firing up and port firing foward into cabin (through ski hole)

?????????????
Everything ive said as far as specs is a good guide line for the xfls, as ive said before 4.25 is a tad too big. id run the amp at 1 ohm if you have access to a dd-1 or a scope id set your amp that way. cant go off oh i turned the knob this much its ok, you would be surprised how quickly you can become hard clipped past 1/4 gain


The gain is not a volume knob. Setting it to 75% wont give you 75% power. It's to match the head units output. With some head units you could get full power out of the amp at the gain at 25% if not lower.

The box sounds great to me. But if you stick that huge port into the ski pass, there won't be much area left for the rest of the sound to come through, and you will mostly get notes near the port tuning. I suggest you still open up your rear deck if you can.

Or you could build a 4th order box where everything comes out of the port, but I doubt you can fit a 4th order for a 15". You'd need at least 6 cubes. I would consider doing two XFL 10s in a 4th order in that vehicle with a rectangular port that fits the maximum size of the ski pass. Then you will have no trunk rattle at all, and the two coils will take the 2400w without a sweat. I'd start with building 1.5 cubes sealed, 3 cubes ported at 45-50hz or so, but people with actual 4th order XFL experience can chime in.
This would also work^

rickymac21
08-29-2013, 09:47 PM
Originally Posted by ancorp

Or you could build a 4th order box where everything comes out of the port, but I doubt you can fit a 4th order for a 15". You'd need at least 6 cubes. I would consider doing two XFL 10s in a 4th order in that vehicle with a rectangular port that fits the maximum size of the ski pass. Then you will have no trunk rattle at all, and the two coils will take the 2400w without a sweat. I'd start with building 1.5 cubes sealed, 3 cubes ported at 45-50hz or so, but people with actual 4th order XFL experience can chime in.


This would also work^

I like the 4th order idea.. I have also wanted to build one but I know there's a lot more to factor in (sub specs) and I'm just not sure how to go about it... Everyone I've read ratios 1:2 (sealed:ported) 1:3 (sealed:ported) and some others too... And apparently that's what makes it difficult, there's no golden ratio...

But since you have experience with the XFL's, would you suggest that ancorp's idea is pretty accurate as far as ratio's for the 4th order? If so how many cubes sealed/ported for the 15?

I know I read that the larger the sealed box is (compared to the ported chamber) the lower the sub will play ?? would 2 cubes sealed, 4 cubes ported be good? tuned to 45 hz

Sorry guys, just trying to figure this out....

97maxima
08-29-2013, 10:17 PM
For a 15 id do 2.25 sealed and 4.5 ported or larger around 1/3 cone area for port which works out to about 14 sq in of port per cube.So 60 ish sq in. tuned in the 45-50hz range

bbeljefe
08-29-2013, 10:22 PM
Prefab 4th orders are the ones that give 4th orders the reputation for being peaky, narrow bandwidth burp boxes. That and poorly designed custom ones.

The thing about 4th and 6th order boxes is that you need to spend some time modeling different configurations and tuning frequencies until you get a wide, smooth passband for the specific driver(s) you're designing it for. Sometimes that means modeling three boxes and sometimes that means modeling thirty boxes. But, you only have to design it once.

And one thing I've found is that I have better luck tuning below the normal 45-50 hz range. Mid to high thirties has been good for most drivers I've done them for.

rickymac21
08-29-2013, 10:37 PM
Prefab 4th orders are the ones that give 4th orders the reputation for being peaky, narrow bandwidth burp boxes. That and poorly designed custom ones.

The thing about 4th and 6th order boxes is that you need to spend some time modeling different configurations and tuning frequencies until you get a wide, smooth passband for the specific driver(s) you're designing it for. Sometimes that means modeling three boxes and sometimes that means modeling thirty boxes. But, you only have to design it once.

And one thing I've found is that I have better luck tuning below the normal 45-50 hz range. Mid to high thirties has been good for most drivers I've done them for.

I am aware that there are many more things to factor in when building one... But is it really impossible to have a general size? I'm not competing, just like to demo and jam... I know that the FS and QTS is in the range for a 4th order... And if I have my net box volume down to the point when I tune the box, I would have to have a "decent" response? If not I can just mess around with different port lengths right??? Do you personally have any suggestions for this particular sub??


For a 15 id do 2.25 sealed and 4.5 ported or larger around 1/3 cone area for port which works out to about 14 sq in of port per cube.So 60 ish sq in. tuned in the 45-50hz range

Is this coming from experience? A recent calculation ? or is this just something general that tends to work with a sub of this size/power??

And just to be clear, the bandpass box would allow the sub to handle more power since it's partially sealed correct?

97maxima
08-29-2013, 10:44 PM
Is this coming from experience? A recent calculation ? or is this just something general that tends to work with a sub of this size/power??

And just to be clear, the bandpass box would allow the sub to handle more power since it's partially sealed correct?[/QUOTE]
All the above, they tend to like a larger sealed section compared to other subs. Has to do with their bl strength which is middle of the road.They will have more cone control and will get pretty loud off not much power. They still will handle a good bit tho. Built one a while back for a pair of xfl 12s firing into the cabin. Very enjoyable listening experience

rickymac21
08-29-2013, 11:01 PM
Well It's settled then.... 4th order it is with the port firing through the ski hole !!!! Thanks maxima for staying in here with me and helping me out ! I really do appreciate all the help and advice.

I have a box designed already ... Just need to know two small things.

1. For port area I know you said about 14 sq in of port per cube... The 'per cube' only pertains to the ported section correct? Might be stupid question but thought I'd ask...
2. Tuning the port is the same as tuning a regular ported box?

bbeljefe
08-29-2013, 11:12 PM
I am aware that there are many more things to factor in when building one... But is it really impossible to have a general size? I'm not competing, just like to demo and jam... I know that the FS and QTS is in the range for a 4th order... And if I have my net box volume down to the point when I tune the box, I would have to have a "decent" response? If not I can just mess around with different port lengths right??? Do you personally have any suggestions for this particular sub??

I don't have any for that sub now but if you decide whether you want to do one of their 15s or two of their tens, I'll be more than happy to model some boxes for you. Just lemme know what driver and how many.

And yeah, once you have a good ratio for the driver you're building for, you can tweak the tuning with an aero port or some other removable port design.

97maxima
08-29-2013, 11:20 PM
Well It's settled then.... 4th order it is with the port firing through the ski hole !!!! Thanks maxima for staying in here with me and helping me out ! I really do appreciate all the help and advice.

I have a box designed already ... Just need to know two small things.

1. For port area I know you said about 14 sq in of port per cube... The 'per cube' only pertains to the ported section correct? Might be stupid question but thought I'd ask...
2. Tuning the port is the same as tuning a regular ported box?
np, yep so 14*4.5=63 sq in. Its the same but since you typically use less port area and a higher tuning you end up with a pretty short port.

rickymac21
08-29-2013, 11:26 PM
np, yep so 14*4.5=63 sq in. Its the same but since you typically use less port area and a higher tuning you end up with a pretty short port.

Cool... Thanks again... Carstereo.com is telling me a box 4.5 cubes with an 8"x8" square port will need to be 15.12" long to get 42 hz.... seems like a long port.. That port will take up about a .5 cubes of airspace...

rickymac21
08-29-2013, 11:28 PM
I don't have any for that sub now but if you decide whether you want to do one of their 15s or two of their tens, I'll be more than happy to model some boxes for you. Just lemme know what driver and how many.

And yeah, once you have a good ratio for the driver you're building for, you can tweak the tuning with an aero port or some other removable port design.

This is for the 15" ... XFL1544 ...

97maxima
08-29-2013, 11:40 PM
Cool... Thanks again... Carstereo.com is telling me a box 4.5 cubes with an 8"x8" square port will need to be 15.12" long to get 42 hz.... seems like a long port.. That port will take up about a .5 cubes of airspace...

thats accurate id bring the tuning up some if you cant afford the length. also if the port is external that would be better

rickymac21
08-29-2013, 11:44 PM
Yea I think I can take the port out about 6" before it starts to interfere with the rear seating area.. I doubt a piece of wood would be comfortable on a passengers back. lol... I'll figure it out though...

bbeljefe
08-29-2013, 11:47 PM
This is for the 15" ... XFL1544 ...


How much air space do we have to work with?

rickymac21
08-29-2013, 11:53 PM
How much air space do we have to work with?

Best dimensions are 17" H x 30" W x 31" D .... 9.1 cubes

ancorp
08-30-2013, 11:37 AM
If you have that kind of room you'd get much louder with two 12" XFLs. But regardless either will sound great.

rickymac21
08-30-2013, 12:19 PM
If you have that kind of room you'd get much louder with two 12" XFLs. But regardless either will sound great.

Yea But 2 12" cost more $$$ than 1 15" ... I'd like to do is especially since the badpass would allow the 12's to get loud on the lows, plus more cone area so more air, but I just can't afford it.

psych0ticnemes1
08-30-2013, 12:49 PM
If you have that kind of room you'd get much louder with two 12" XFLs. But regardless either will sound great.

Surface area isn't everything. The 15" could very well be louder. It depends on the box and power.

rickymac21
08-30-2013, 01:24 PM
Surface area isn't everything. The 15" could very well be louder. It depends on the box and power.

Well have you ever used the xfl 15 in a 4th order bandpass?? That's what I intend to do. The amp will be a hifonics brx2400 so ill have plenty of power. (Stock 120a alt, big 3, 0 gauge power/ground, 4 gauge for speaker wire).

With some recommendations on here I've designed a 4th order with a sealed chamber of 2.23 cubes net and ported chamber of 4.25 cubes net. 8"x7" square port tuned to 40-42 hz