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mopower440
01-11-2012, 07:47 PM
Got my box done for my single 10" sub for under the back seat of my extended cab chevy truck,, it is a downfire design. Not happy with the sound. It is quite punchy and sounds good listening to rock and metal, but as far as rap or hip hop, it doesnt have that low rumbling BOOM i was expecting it to. I had this same sub and amp in my old REGULAR cab truck behind the seat in an even smaller box and it had that low rumbly thunderous BOOM even in it.smaller cab and smaller box!.I expected it to do better in the extended cab being there is more space and the box is bigger. Maybe downfiring it wasnt the right box to build? It is a sealed enclosure. The sub is an old school mtx blue thunder and calls for 1/2 to 1 cu. ft. of space. As i said, the box is bigger than my previous box and it boomed in that smaller box. Wish i would have built it upfiring now i guess, would iy have done better upfiring?

DoesDad
01-11-2012, 07:52 PM
You would've been better off not using a sealed box. I don't know if you have the space to go ported where you wanna put that thing though?

audiobaun
01-11-2012, 09:31 PM
Yes ported would be ideal.I had a down fire set up, and felt the same from it.As though from the sub firing into the carpet seemed to me it was deadning the sound out, and I ended up placing plywood just under where the sub was firing down , to make the sound reflect back up.Sounds almost stupid, but try a piece of plywood that way, before you go to rebuilding that box.I ran it like that for almost a yr, and what a difference it made, rather than down firing into the carpet, and deadining out.

DoesDad
01-11-2012, 09:45 PM
That's really a good idea. The carpet probably does deaden it a lot!

mast240
01-11-2012, 09:53 PM
You said the sub calls for a 1/2 cubed... but not the size of the new box?

mopower440
01-11-2012, 10:04 PM
about .9

mast240
01-11-2012, 10:06 PM
I'm going to say that your box is a lil too big, and that's a big reason ur losing out on the lows

hispls
01-11-2012, 10:21 PM
I'm going to say that your box is a lil too big, and that's a big reason ur losing out on the lows

Lulwhat?

Larger box = more low extension in sealed.

Try flipping the box firing a different direction and changing positions, if it helps build a new box firing whatever direction is best. That's not a bad sub for what it is. A friend of mine ran a single 10 in a hatchback and it did better than I expected.

Louisiana_CRX
01-11-2012, 10:26 PM
IF THE SUB TAKES A .5 SEALED...then .9 ported ought to be about right...add an external 3" port 22" long it should sound a lot better...be sure to load the port...for better low end...

Moble Enclosurs
01-12-2012, 03:44 PM
You guys need to understand that the recommended box size from the manufacturer is not a good thing to go on because it does not account for driver placement, ratios, or resonances. OP, what is the driver you are using?

huricaine
01-12-2012, 03:50 PM
downfiring a sub/seal it "for lows" in a small cabin goes around alot but it's bs lol. Flip the sub. It honestly dosn't matter as much where the sub is at in a small cabin vs a bigger one but you shouldn't have the cone too close to anything as that sort of gain is better for upper end.

CADENCE SOUND
01-12-2012, 03:52 PM
Got my box done for my single 10" sub for under the back seat of my extended cab chevy truck,, it is a downfire design. Not happy with the sound. It is quite punchy and sounds good listening to rock and metal, but as far as rap or hip hop, it doesnt have that low rumbling BOOM i was expecting it to. I had this same sub and amp in my old REGULAR cab truck behind the seat in an even smaller box and it had that low rumbly thunderous BOOM even in it.smaller cab and smaller box!.I expected it to do better in the extended cab being there is more space and the box is bigger. Maybe downfiring it wasnt the right box to build? It is a sealed enclosure. The sub is an old school mtx blue thunder and calls for 1/2 to 1 cu. ft. of space. As i said, the box is bigger than my previous box and it boomed in that smaller box. Wish i would have built it upfiring now i guess, would iy have done better upfiring?

Try playing with the "bass-boost" settings, i find that it actually helps in sealed enclosures.
But your best bet, would be to go with a ported enclosure..

Down firing should not effect it much, being that it is very close to you.

Moble Enclosurs
01-12-2012, 03:58 PM
Try playing with the "bass-boost" settings, i find that it actually helps in sealed enclosures.
But your best bet, would be to go with a ported enclosure..

Down firing should not effect it much, being that it is very close to you.

The problem with that though, is induced distortion that in a sealed enclosure will not be very noticeable, especially with resistance between the enclosure placement and the drivers listening position. Bass boost was not designed to control distortion levels......which are very important in sealed applications because of the controlled compression on the driver, mechanically there will be no changes, but thermally......be careful with that.

huricaine
01-12-2012, 04:04 PM
Also the driver beeing close to you is not important for the low end as the low end in small cabins is uniform throughout, for the most part.

Moble Enclosurs
01-12-2012, 06:25 PM
Also the driver beeing close to you is not important for the low end as the low end in small cabins is uniform throughout, for the most part.
Yes, for the most part, you will get a compression contant, but only at high power levels. When playing at normal volumes or less, the distance involved can make a difference in output and the more sensitive the ear will be to changes in the response. Dips and peaks do occur even at low end frequencies, but you have a good point at there being a uniformity, and for all those who want to understand this concept that huricaine mentioned, it is no different than thinking of the inside of a car as the inside of an enclosure. Great point!

mopower440
01-12-2012, 07:36 PM
well, i tried flipping the box over making the sub face upwards, didnt make much difference, tried facing it backwards, still not much difference. I just dont understand. The sub calls for 1/2 to 1 cu. ft. in a sealed box. ok, i had the same sub in a slightly smaller box in my single cab truck with the back of the seat right up against the sub grill and it still rumbled quite well. I dont see why it doesnt sound right in a box that is sized better..its not much bigger than the one in my old truck but a little.

huricaine
01-12-2012, 07:40 PM
Yea, that's why i said for the most part because i know low frequencies can also resonate some....but not as easily as the upper ones. That's also a great point about the power level.

mopower440
01-12-2012, 07:49 PM
the box i built is almost identical to this one
http://www.ebay.com/itm/GMC-SIERRA-EXTENDED-CAB-1999-07-SIN-10-BLACK-SUBWOOFER-SUB-ENCLOSURE-BOX-/280778661312?pt=LH_DefaultDomain_0&vxp=mtr&hash=item415fb65dc0

Moble Enclosurs
01-12-2012, 08:47 PM
well, i tried flipping the box over making the sub face upwards, didnt make much difference, tried facing it backwards, still not much difference. I just dont understand. The sub calls for 1/2 to 1 cu. ft. in a sealed box. ok, i had the same sub in a slightly smaller box in my single cab truck with the back of the seat right up against the sub grill and it still rumbled quite well. I dont see why it doesnt sound right in a box that is sized better..its not much bigger than the one in my old truck but a little.

Though everything is reliant on other factors, the fact that you had the same driver in a smaller box with more low end output raises questions a lot about the setup...such as.......are you using the same amplifier, HU, etc also? The thing is, since it is a different vehicle, it can have a completely different response regardless of minimal or even no changes in the actual design. BUT.......it does seem like other factors are involved, like amp settings, etc since you said it was the same driver. BUT.....this does not delete the fact that a different and more optimized design can still be obtained. What sub are you using? Im not sure if that was mentioned or not yet.

huricaine
01-12-2012, 09:00 PM
Where IS the sub placed? Rear of vehicle or not? Regaurdless of my, and other's theory explainations i have heard plenty of people findout that their low end is ALOT better when the sub is at the rear of the vehicle. I mean, it is KNOWN that SPL is generally higher when the subwoofer is at the rear of the vehicle due to cancellation but lower frequencies tend to be less an issue here, but like i said, everyone claims and even proves by meter that the rear is the best and i've always personally gave the SAME advice, to place the sub in the far rear. Always worked for me aswell.

Moble Enclosurs
01-12-2012, 09:17 PM
downfiring a sub/seal it "for lows" in a small cabin goes around alot but it's bs lol. Flip the sub. It honestly dosn't matter as much where the sub is at in a small cabin vs a bigger one but you shouldn't have the cone too close to anything as that sort of gain is better for upper end.


ahhhh. not necessarily. Due to loading factors, the down-firing of a driver, depending on the type of down-fire(slanted, constant area) under the driver, will, much like having the cone closer to any object, aid in the low frequency response IF IT IS DONE CORRECTLY. But having it just down-fire to say a floor with no other resonance barriers within 2 ft at most of the designs driver output location (not port output for this case), will have such a small effect that it will be inaudible. The main thing that it changes is the phase response of the passband, which in turn can cause possible cancellation of certain frequencies depending on the out of phase areas within the passband along with the frequency band of those out of phase areas. Meaning that if it were out of say a greater than 90 degree phase(for sealed designs, which anechoically cannot happen-this is only for boundary effects) for only a 3Hz band, then also depending on the rest of the phase within the passband of the system, it will determine the cancellation effect involved when playing multiple tones, such as a music recording.

What that says is, when down-firing a design, or even trunk loading it through a blowthrough area without incorperating that area as part of the loading effects on the design, it will have an effect either audible or not on the LF response EVEN THOUGH the most part of the LF band is acoustically smaller than the cabin area( a small on as the example).
I see what you are saying, but there is much more involved than what you can "hear" in an audio system. Take for instance a HF response in a larger room vs a smaller room. You can noticably hear the difference in phase shifting at specific positions causing cancellation not even related to the physical part of the design other than directivity. But put it is a smaller room that is in fact acoustically small compared to the passband used, and you will not notice audibly the phase changes as easily, though they still happen. Ever put your head closer to the window and hear the bass increase? Or into a corner due to gain? This is the same effect as in phase response. Most of the area outside of a 45 degree span on either side of the 0 degree listening position is out of phase from the systems response, and has an effect on audible and inaudible changes. This happens even in a vehicle with sub frequencies. Its just less noticable when two things occur.......1. you base it on a single listening position, and 2. you have the acoustical pressure(spl) increased per square inch to a point where the resonances are camoflouged into the space due to timing effects and intensity over time.

here is an example: a speaker is in front of you, playing at a certain level where you can hear it at a certain db level as well. Now, say you increase the distance between you and the speaker. What happens to the dB levels? They decrease due to time and distance over intensity. Now, what happens when the level(volume) is decreased? You hear it also with less dB output. Two factors that create a major part in sound reproduction based on propagation. These still occur in any given space regardless of size. But lets say you put resonant walls on each side of the speaker between you and the speaker where the mirrored out of phase imagery of the signal reflects directly to the listener? you increased the dB level based on resonance even though it took more time to get there as a resonance, the loss in dB that is an important factor in resonance is considered to be nulled greater than a -60dB level. So, if that resonance hits you before the original signal decreases to a point greater than -60dB, than the dB level at the listening position is increased by the dB level created from the reflected signal. So, in a vehicle, this reflective dB increase happens so frequently, that an audible difference if pressure and intensity is increased based on power levels, is less noticable from so many of these reflections occuring before the original signal is greater than -60dB over a specific time(usually measured in ms).

So, I can see how you mean that if the size of the cabin is small (compared to the frequency), that placement and such are not a factor. But when time constants and intensity are involved, they become a huge factor, especially when dealing with stereo imaging, but for sub frequencies as well even though they span over a greater distance. So, yes, the placement can be less sensitive over a smaller area based on time and distance, but still can have an effect on the sound whether audible or not, such as the cancellation effects caused by phase changes, which are based on placement and positioning as well. And since those phase changes can effect the response output, then it directly related to the frequency response of the system.

I typed this really fast, so I apologize if there are mistypes or it becomes confusing. I might have jumped around a bit, but the concept should be that regardless of how intense the effect is on any change in the physical part of a design within its environment, it still can have a huge factor or role on the outcome of the response if not carefully considered.

Moble Enclosurs
01-12-2012, 09:23 PM
Where IS the sub placed? Rear of vehicle or not? Regaurdless of my, and other's theory explainations i have heard plenty of people findout that their low end is ALOT better when the sub is at the rear of the vehicle. I mean, it is KNOWN that SPL is generally higher when the subwoofer is at the rear of the vehicle due to cancellation but lower frequencies tend to be less an issue here, but like i said, everyone claims and even proves by meter that the rear is the best and i've always personally gave the SAME advice, to place the sub in the far rear. Always worked for me aswell.

This is a great point! OP pay attention to this because this is very true. Placing the enclosure in the middle of a vehicle can cause the cancellation effects that I recently mentioned. And I calculate for it quite frequently when dealing with sql designs. So, placement is in fact very important.

mopower440
01-12-2012, 09:55 PM
It is under the rear seat. i tried flipping the box over so sub was pointing up and helped very little and tried it pointing every other way also, with the same results. very dissapointed and dont really know what to do. Ive built several sealed boxes for different vehicles before and always had good results until now. even back when i built boxes that were a little to small so they would fit behind the seat in single cab trucks they sounded great, this should have been easy being i had more room so i could do a bigger box and all, makes no sense. I hope i explained it right, when the bass drum kicks like on metal or rock, it does sound good, real hard and punchy. Its the boomy carrying thunder type bass, like in rap music, that it doesnt do well at all! You would think since it punches hard on regular music it would also with the other..really dont know what to do with it. BTW, its an old school mtx blue thunder ive used in every vehicle ive owned and had great results until now. also using the same amp that ive also used with this woofer..should i try to port it? if so, where should the port be? keep in mind the link i posted so you can see what the box looks like, under the back seat on an extended cab truck. The sub is under the drivers side and the box extends over the transmission hump. Go here and the plans for the box i built are the top one in the picture except i cut one side off because i only used one single sub..http://www.ls1truck.com/forums/audio-multimedia/37010-extended-cab-subwoofer-box-dimensions.html

Moble Enclosurs
01-13-2012, 12:23 AM
It is under the rear seat. i tried flipping the box over so sub was pointing up and helped very little and tried it pointing every other way also, with the same results. very dissapointed and dont really know what to do. Ive built several sealed boxes for different vehicles before and always had good results until now. even back when i built boxes that were a little to small so they would fit behind the seat in single cab trucks they sounded great, this should have been easy being i had more room so i could do a bigger box and all, makes no sense. I hope i explained it right, when the bass drum kicks like on metal or rock, it does sound good, real hard and punchy. Its the boomy carrying thunder type bass, like in rap music, that it doesnt do well at all! You would think since it punches hard on regular music it would also with the other..really dont know what to do with it. BTW, its an old school mtx blue thunder ive used in every vehicle ive owned and had great results until now. also using the same amp that ive also used with this woofer..should i try to port it? if so, where should the port be? keep in mind the link i posted so you can see what the box looks like, under the back seat on an extended cab truck. The sub is under the drivers side and the box extends over the transmission hump. Go here and the plans for the box i built are the top one in the picture except i cut one side off because i only used one single sub..Extended cab subwoofer box dimensions (http://www.ls1truck.com/forums/audio-multimedia/37010-extended-cab-subwoofer-box-dimensions.html)

Knowing that now, it seems to be due to linear excursion capabilities. Usually, when excursion is exceeded in a design, there is a loss of output from mechanical limitations being met. Just from some rough estimations, I gathered that in a 1 cubic ft enclosure, the excursion from this driver (with calculated specifications only), reaches xmax in a sealed design on 250W@4ohms@48Hz. Which means that anything below 48Hz is where you are having problems gathering at least even a smooth output from. You are getting around a resonant peak of 63Hz, which I would imaging sounds pretty great at that frequency with the velocity from the front of the driver. Efficiency peak is around 7% at most and is very narrowbanded, which means it will take a lot of power to get any output below the 48Hz mark, which is ironically at the peak 5%(of the 1-5% average) of a normal enclosure.

So, to fix this output from a sealed design, you will need to go smaller on the volume to control the excursion that is likely causing some distortion below 45Hz right now as it is, trying to push it. Normally, one would say that going larger will give you more low end, but this is why I enforce optimized enclosure specifications from my figures because if you end up going too large (which is possible even with a sealed design), then you lose compression capabilities of the driver and in return lose efficiency which relates to power limitation issues.

The best option here would definitely be going ported because this driver seems to enjoy a ported enclosure much more than sealed. BUT, if you were to keep sealed, go with a compression volume of .53 cubic ft (not including displacement) for optimum sealed output. If you find that the low end from that is still suffering.....it is not only due to personal preferences, but the fact that this particular driver works more efficiently in a conventional ported design......and not all do.

I hope that helps..and if you can, for others involved in the thread.........can you verify that the 48Hz mark and the 63Hz area shows some sort of relevancy to what you are hearing (within +/- 3Hz). Thanks!

mopower440
01-13-2012, 07:35 PM
well, i dont think im explaining whats going on right, I think it is hitting the very low frequencies because the kick of a bass drum like in rock music is a very low frequency and it sounds great on that kind of music because it is real 'punchy' , like it 'kicks' the seat when the kick drum hits. The problem is that booming type bass thats in rap music, the kind that kinda rumbles and carrys..it doesnt do that well, still kinda punchy and doesnt do the smooth 'rumble'.The box isnt all that big, just a hair bigger than the one that was stuck behind the seat of my single cab truck and it did much better and that box was i beleive too small. The sub calls for .5 to 1 cu. ft. and im still under 1. what do you think? I hope im explaining it right, wish you could hear it so you would know.

audiobaun
01-13-2012, 07:40 PM
Need to take into consideration of the overall vehicle airspace as well, may be more than the last vehicle ??????Just my 0.02cents

Moble Enclosurs
01-13-2012, 09:03 PM
well, i dont think im explaining whats going on right, I think it is hitting the very low frequencies because the kick of a bass drum like in rock music is a very low frequency and it sounds great on that kind of music because it is real 'punchy' , like it 'kicks' the seat when the kick drum hits. The problem is that booming type bass thats in rap music, the kind that kinda rumbles and carrys..it doesnt do that well, still kinda punchy and doesnt do the smooth 'rumble'.The box isnt all that big, just a hair bigger than the one that was stuck behind the seat of my single cab truck and it did much better and that box was i beleive too small. The sub calls for .5 to 1 cu. ft. and im still under 1. what do you think? I hope im explaining it right, wish you could hear it so you would know.

I think you explained it perfect. The recommended volume I have is .53 cubic ft. Any variation of this due to the size, will cause different effects. And yes, as mentioned in the previous post, the vehicle does make a difference as well. Most of the gain you hear right now is from the vehicle. SO, you explained it fine, and I am telling you like I did in the last post.........this sub likes ported better, which will give you (if designed right) the bass you are talking about. The "carrying" part is not from the design, but the output needs to be intense for it to carry like you are talking about. The "carrying" is from resonances over time.which is more vehicle related. I hope that makes sense to you.

mopower440
01-13-2012, 10:17 PM
wasnt meaning 'carrying bass' as in heard coming blocks away, i was speaking about inside the car only. good example, if you have a huge churchbell and hit it, it has a drawn out' duuuuuuunnnnnnnnnnnggggggggg',(rap music) now take the same churchbell and only this time have someone wrap there arms around it and hit the bell again, this time its a quick and punchy 'duuung', thats what im experiencing when trying the real boomy rap music, doesnt do good on it but is real punchy on the metal. it just acts more like its in too small of a box rather than too big, but as i stated earlier, ive used a smaller box before and was fine..you still think its too big? If so i may remove the sub and put some wood in the box to take up some space and try it again.

Moble Enclosurs
01-13-2012, 10:32 PM
wasnt meaning 'carrying bass' as in heard coming blocks away, i was speaking about inside the car only. good example, if you have a huge churchbell and hit it, it has a drawn out' duuuuuuunnnnnnnnnnnggggggggg',(rap music) now take the same churchbell and only this time have someone wrap there arms around it and hit the bell again, this time its a quick and punchy 'duuung', thats what im experiencing when trying the real boomy rap music, doesnt do good on it but is real punchy on the metal. it just acts more like its in too small of a box rather than too big, but as i stated earlier, ive used a smaller box before and was fine..you still think its too big? If so i may remove the sub and put some wood in the box to take up some space and try it again.

No kidding, lol. Yes, that is the "carrying" I am referring to as well. Again, It is called resonance. And I will say again also, I have calculated it for an optimum .53 cubes, but it does enjoy ported more......not because ported will give it more low end, but because that is just what the drivers mechanical operation will enjoy the most for efficiency.
So, if your sealed is larger than .53, try to make it smaller. But I will not revert from the recommendation of going ported still. You will likely not gain the low end you are looking for with a smaller enclosure, but it does give it better excursion control below the mentioned 48Hz LF cutoff of mechanical limitations, so havign it smaller will help in that aspect. But since the low end is mainly "carried" from vehicle resonances, then a ported enclosure will do much more wonders than a sealed for this driver any day.

Pretty informative explanation though....I like that. :D

mopower440
01-13-2012, 11:09 PM
well, i wouldnt mind trying to port it. would need you help on where to put the port on this weird shaped box.

Moble Enclosurs
01-14-2012, 01:40 AM
Wouldn't mind helping either :D Just PM me when you want.

i2ain2thunder
01-14-2012, 02:21 AM
2 Possible solutions:
1. Build a smaller enclosure or a ported enclosure
2. Keep current enclosure and buy an amp that can produce a good amount more power

Moble Enclosurs
01-14-2012, 02:42 AM
2 Possible solutions:
1. Build a smaller enclosure or a ported enclosure
2. Keep current enclosure and buy an amp that can produce a good amount more power

As long as that power does not exceed the thermal limits of the driver

mopower440
01-14-2012, 06:06 PM
well, i stuffed some of the box with blocks of wood. It didnt seem to help with what im after, it just made it to where i could turn up the volume a few more notches before the sub started to distort. dont know why i cant get the low rumble..I built a sealed box for the trunk of my saturn with a mtx 10" and it just sounds perfect all around, got to get this truck system right now,

audiobaun
01-14-2012, 06:11 PM
That S U C K S man..Sounds like a rebuild on the way.:crap:

snyderd758
01-14-2012, 08:19 PM
That S U C K S man..Sounds like a rebuild on the way.:crap:nah maybe just time for a new sub.And build a ported box to spec if you want more volume.....

mopower440
01-15-2012, 12:16 PM
weird thing, i was playing around with it and i took the sub out of the box and for the heck of it i inverted the sub and set it over the hole in the enclosure and it did much better like that, better low carrying bass. Not enough room under seat to build a box for inverted sub though.

Buck
01-15-2012, 02:03 PM
Need a box design? :D

audiobaun
01-15-2012, 02:59 PM
nah maybe just time for a new sub.And build a ported box to spec if you want more volume.....

Uh ya ..rebuild..Buck can help you out man.Doesnt hurt to ask

mopower440
01-15-2012, 05:20 PM
I beleive mobile enclosures hit the nail on the head! I removed the sub from the box and did some measuring inside the box and cut a board and made a dividing plate and installed in the box wich blocked off maybe 40% of the box and i beleive that helped quite a bit. Now the lows can actually be heard and felt and feels more solid instead of hollow. I dont think its 100% of what it should be but it did get much better. So now i need to decide if i want to just port the current box being its too big for sealed, or, just build a smaller sealed enclosure..not really sure where or how to port tho, always done sealed..

Moble Enclosurs
01-15-2012, 07:43 PM
Well, I am glad that what you did helped in the way we had thought it would. It is very important, and this is a great example, to use a recommended volume (and mine was within the manufacturers of .5-1[mine was at .53]) in order to control the driver the way it was meant to. I think at this point, you are going to get as much as you can out of that sub in that box being that it is closer to the recommended volume. Either a properly sealed one, or again, a recommended ported one would be ideal. I will answer you PM in a ***, I just wanted to get back to the responses on here to show how important it is to use the right specifications.

Moble Enclosurs
01-15-2012, 07:52 PM
haha I cant believe it edited the word s e c as in second. wow. Anyhow, I got to your PM OP, and I hope we can help you out with everything. If not, I know Buck offered as well. You should hit him up also to keep your options open. :D

mopower440
01-15-2012, 07:59 PM
guys, if i go ported i would like to keep the box ive already built an just port it because it did turn out very nice and fits truck perfectly..can you tell me how to port it?
thanks

mopower440
01-17-2012, 08:08 AM
I am noticing it still doesnt do the real lows well, the sub is vibrating but not much sound or feel. I got less power in my car and the lows feel like the car is sitting on an earthquake when the lows hit. just cant get that out of this truck sysytem. what gives?

Moble Enclosurs
01-17-2012, 08:19 AM
I am noticing it still doesnt do the real lows well, the sub is vibrating but not much sound or feel. I got less power in my car and the lows feel like the car is sitting on an earthquake when the lows hit. just cant get that out of this truck sysytem. what gives?

You cannot expect much more out of it at this point for a sealed enclosure because it is not as efficient in a sealed than ported, unless you are talking now that you have ported it since then. Did you port it yet? And did you make sure the divider was sealed correctly to control the volume compression? There is a lot that can be done still, but you have not explored the other options yet.

Also, You cannot take the response from one vehicle and compare it effectively to another as it will have a different effect on the response also, so just because it was better in one vehicle does not mean it will be in another......even in a different size box......since it is the type of box that will make the difference. Does that help a little?
Even though, yes, the LF response can have, as mentioned, a constant, there will exist in some vehicles points of cabin loss (</= 0dB gain) at even low frequencies below the cabin's 1st and second order resonances. This can occur due to placement, not direction. Where the box is located will have a huge effect on the response and it seems that where it is....is just not working for you. Try putting it in different locations (temporarily) such as the back seat(if you have one), in the corner, as much as possible, and other locations until you can possibly hear some sort of difference.
Without the measurements of the vehicle and other factors, I cannot give you any advice on placement yet, unless a design is to be purchased for calculations, but try those things and again, port that mofo, lol.
I really hope that you find some changes that help soon. :D

mopower440
01-17-2012, 12:40 PM
can you guide me on how to port this box?
thanks

mopower440
01-17-2012, 09:31 PM
need to know how big and how long to make the port..?

Moble Enclosurs
01-20-2012, 04:57 PM
I sent you a PM and I believe we were talking about how you can get me a pic of the area. So, once you get that going, Ill check on that port that I mentioned in the PM. :D

mopower440
01-20-2012, 09:43 PM
http://i4.photobucket.com/albums/y128/mopower440/DSCN0297.jpg

Moble Enclosurs
01-21-2012, 03:03 AM
That is what I figured you meant. Thank you for the picture. It looks as if you can utilize a round port for this without having to modify too much. Most of the port can go into the enclosure also. From very very rough calculations, I figured you can utilize a single 3" round port that will go into the current setup about 19" and get a response at least down to 34-35Hz with more authority than you have now. I say only around 34Hz due to port noise being introduce likely below that at max power. But below max power, around music level, you should be fine to around 30Hz. Max voltage is about 32V, and music voltage is about 22.4V (calculated).
I really hope this helps you out at least a little. So, if you make a hole to fit a 3" round port into it and make it about 19" you will get a better low end response. Not optimum, but better without a rebuild.

mopower440
01-21-2012, 10:05 AM
Thanks ME, where do i put the port though?

Moble Enclosurs
01-21-2012, 01:06 PM
On the side that was cut off from the rest.......and it should go through the side and into the bigger chamber area. Make sure it does not touch the driver. If 19" is too long, which it should not be because based on the halving the design before, you should have more than 19 before the driver, then don't go less than 18". make sense?

mopower440
01-21-2012, 01:37 PM
yes sir. Thanks again.

Moble Enclosurs
01-21-2012, 01:51 PM
Not a problem! you are welcome, and if you have any more questions, you know where to find me. :D