good match?

[Gioia69 30]

for my next setup i was thinking of doing an 18" btl out of a 2002 pontiac grand prix's trunk on a sundown 3500d. it seems thats what everyone likes to pair up with the btl. this is for a daily system. and the box would probably be like 6 cubes tuned to mid 30s. is this a solid setup? how much wattage do u guys think it will actually see after impedance rise? should i just get a 2000 watt rms amp or roll with the 3500 like i was planning on? and i know this is a difficult question to answer, but does anyone have any experience of any setups like this playing out of a trunk? obviously it all depends on the install and blah blah blah, but i was figuring id make somewhere around 145 db. does that sound about right? all comments and advice is appreciated. thanks.

[Lucky 76 5]

If that is with port and displacement calculated in you better make a bigger box. Minimum space is never a good call. If you can squeeze more out of the box size I definately would. As for the 3500 I wouldnt use it to power that sub for daily unless you plan on tuning it down. That amp will put out close to 4kw rms at 1 ohm. Impedence rise does not matter. For every hike in impedence there is also a drop in impedence when listening to music because of numerous sine waves. If you were competing and you were to play strictly tones this would be a differnent story as you could calculate the impedence rise of that single sine wave. I understand the BTL is capable of 2000+ rms but surely it is not able to withstant almost double its rated power for very long. I would stick with around 2500 rms on a loaded btl if I were you.

This is straight from Fi

BTL 18 – Ported box we recommend using 5-8 cubic feet @ 30-35Hz tuning, you can tune a little higher if you wish but we recommend keeping it close to 32hz for a daily driver. Again the same 12-16 square inches of area applies per cubic foot of volume.

[kross6622 0]

There is no way to fit an 18in btl in a grand prix unless u plan on taking out the back seats. a 4.45 cubic foot box tuned to 28 hrtz leaves you with very little room. I have an 07 so it may not be exactly the same size but, if you want to push 3500 watts you will need extra batterys, etc, and there will not be enough room for it. I suggest a 15 btl. As for your amp, if you are goign to have turned down then I'd say get the 3500 if you can afford it, but dont expect to use over 2500.

Just my .02

[///M5 2,833]

Bad plan. You can't fit an 18, you shouldn't even think about impedance rise, and that is more power than you need for a BTL.

[Lucky 76 5]

You could probably fit it if you were so face the sub up towards the trunk and have the port facing the cabin. Pontiacs have some big trunks but that is also going to require a big box. You should see what the max dimensions you have for the box and then post them over here.

[Duran 387]

Don't try to fit an 18" in there; and don't count on impedance rise. Stick with 2 12's as they would work better with your airspace vs. one 15" or 18".

[Lucky 76 5]

ya its a much better idea to go with 2 12s. Not only would you have more cone area but you could buy 2 of the baseline btls or get 2 of the btls fully loaded and you would be fine for that 3500 watter

Edited August 20, 2009 by Lucky 76

[Gioia69 30]

Bad plan. You can't fit an 18, you shouldn't even think about impedance rise, and that is more power than you need for a BTL.

idk man. i dont have the pontiac now, but i had one before, it was a '98, so its the same body style as the 02 im gonna get. that definitly has a bigger trunk than my 94 buick regal, and right now i have a box thats exactly 4 cubes after port, driver and mdf displacement. and the only issue was getting it into the trunk, not it fitting. i think i could get a box thats 6 cubes in there after all displacements. and yeah i was planning on tuning it low if i was gonna roll with the 3500 watts. probably not in the 20s, but somewhere between 30 and 33 hz.

[Gioia69 30]

There is no way to fit an 18in btl in a grand prix unless u plan on taking out the back seats. a 4.45 cubic foot box tuned to 28 hrtz leaves you with very little room. I have an 07 so it may not be exactly the same size but, if you want to push 3500 watts you will need extra batterys, etc, and there will not be enough room for it. I suggest a 15 btl. As for your amp, if you are goign to have turned down then I'd say get the 3500 if you can afford it, but dont expect to use over 2500.

Just my .02

im aware i need good electrical for an amp like that. i wouldnt even be able to run 2000 rms without electrical upgrades.

[Gioia69 30]

If that is with port and displacement calculated in you better make a bigger box. Minimum space is never a good call. If you can squeeze more out of the box size I definately would. As for the 3500 I wouldnt use it to power that sub for daily unless you plan on tuning it down. That amp will put out close to 4kw rms at 1 ohm. Impedence rise does not matter. For every hike in impedence there is also a drop in impedence when listening to music because of numerous sine waves. If you were competing and you were to play strictly tones this would be a differnent story as you could calculate the impedence rise of that single sine wave. I understand the BTL is capable of 2000+ rms but surely it is not able to withstant almost double its rated power for very long. I would stick with around 2500 rms on a loaded btl if I were you.

This is straight from Fi

BTL 18 – Ported box we recommend using 5-8 cubic feet @ 30-35Hz tuning, you can tune a little higher if you wish but we recommend keeping it close to 32hz for a daily driver. Again the same 12-16 square inches of area applies per cubic foot of volume.

6 cubes after driver, mdf and port displacement sounds big enough for me

[Gioia69 30]

You could probably fit it if you were so face the sub up towards the trunk and have the port facing the cabin. Pontiacs have some big trunks but that is also going to require a big box. You should see what the max dimensions you have for the box and then post them over here.

thats what i planned on, sub up , port towards cabin. i dont know the dimensions though cuz i dont have the car yet.

[Duran 387]

If that is with port and displacement calculated in you better make a bigger box. Minimum space is never a good call. If you can squeeze more out of the box size I definately would. As for the 3500 I wouldnt use it to power that sub for daily unless you plan on tuning it down. That amp will put out close to 4kw rms at 1 ohm. Impedence rise does not matter. For every hike in impedence there is also a drop in impedence when listening to music because of numerous sine waves. If you were competing and you were to play strictly tones this would be a differnent story as you could calculate the impedence rise of that single sine wave. I understand the BTL is capable of 2000+ rms but surely it is not able to withstant almost double its rated power for very long. I would stick with around 2500 rms on a loaded btl if I were you.

This is straight from Fi

BTL 18 – Ported box we recommend using 5-8 cubic feet @ 30-35Hz tuning, you can tune a little higher if you wish but we recommend keeping it close to 32hz for a daily driver. Again the same 12-16 square inches of area applies per cubic foot of volume.

6 cubes after driver, mdf and port displacement sounds big enough for me

A 15" or 2 12's in a good enclosure that's actually large enough will be louder than an 18" being choked in 6 cubes.

[Gioia69 30]

Don't try to fit an 18" in there; and don't count on impedance rise. Stick with 2 12's as they would work better with your airspace vs. one 15" or 18".

i want to keep things as light as possible. 2 12's would mean another whole motor. and btls weigh like what... 70 lbs? i was thinking a d3100 up front and one more in the trunk, along with the amp, box and sub. and i was thinking the 18 because 1 18 btl has an effieciency of 94.9 db and 2 btls would be 93.5 db (90.5 + 3). but idk you know this is still far away. i have 0 dollars and i owe like 500 dollars to the government and im unemployed and a system like this is gonna be expensive so its gonna be a while til it actually happens anyways. and by that time, the AA *** sub is gonna be out and i might end up getting that. but i really do think i could get an 18 in there. it would be a bitch. but i think it could be done.

[Gioia69 30]

If that is with port and displacement calculated in you better make a bigger box. Minimum space is never a good call. If you can squeeze more out of the box size I definately would. As for the 3500 I wouldnt use it to power that sub for daily unless you plan on tuning it down. That amp will put out close to 4kw rms at 1 ohm. Impedence rise does not matter. For every hike in impedence there is also a drop in impedence when listening to music because of numerous sine waves. If you were competing and you were to play strictly tones this would be a differnent story as you could calculate the impedence rise of that single sine wave. I understand the BTL is capable of 2000+ rms but surely it is not able to withstant almost double its rated power for very long. I would stick with around 2500 rms on a loaded btl if I were you.

This is straight from Fi

BTL 18 – Ported box we recommend using 5-8 cubic feet @ 30-35Hz tuning, you can tune a little higher if you wish but we recommend keeping it close to 32hz for a daily driver. Again the same 12-16 square inches of area applies per cubic foot of volume.

6 cubes after driver, mdf and port displacement sounds big enough for me

A 15" or 2 12's in a good enclosure that's actually large enough will be louder than an 18" being choked in 6 cubes.

you really think 6 cubes is choking an 18? i have no experience with 18s but that just doesnt seem right. my 15" fi bl is in 4 cubes and i think it does very well for itself and sounds great. and isnt 6 cubes too big for a single 15?

[Gioia69 30]

If that is with port and displacement calculated in you better make a bigger box. Minimum space is never a good call. If you can squeeze more out of the box size I definately would. As for the 3500 I wouldnt use it to power that sub for daily unless you plan on tuning it down. That amp will put out close to 4kw rms at 1 ohm. Impedence rise does not matter. For every hike in impedence there is also a drop in impedence when listening to music because of numerous sine waves. If you were competing and you were to play strictly tones this would be a differnent story as you could calculate the impedence rise of that single sine wave. I understand the BTL is capable of 2000+ rms but surely it is not able to withstant almost double its rated power for very long. I would stick with around 2500 rms on a loaded btl if I were you.

This is straight from Fi

BTL 18 – Ported box we recommend using 5-8 cubic feet @ 30-35Hz tuning, you can tune a little higher if you wish but we recommend keeping it close to 32hz for a daily driver. Again the same 12-16 square inches of area applies per cubic foot of volume.

6 cubes after driver, mdf and port displacement sounds big enough for me

A 15" or 2 12's in a good enclosure that's actually large enough will be louder than an 18" being choked in 6 cubes.

and dont a lot of ppl put 18s in 5 cubes? or are they just stupid? what would YOU consider to be the minimum box size for an 18 without choking it?

[Duran 387]

you really think 6 cubes is choking an 18? i have no experience with 18s but that just doesnt seem right. my 15" fi bl is in 4 cubes and i think it does very well for itself and sounds great. and isnt 6 cubes too big for a single 15?

That's almost the MAXIMUM airspace for a 15", that would be why. it's more efficient.

and dont a lot of ppl put 18s in 5 cubes? or are they just stupid? what would YOU consider to be the minimum box size for an 18 without choking it?

It really is stupid to put an 18" in 5 cubes, that's the bare minimum and the maximum airspace for a 15", in that alignment the 15" in the better box would outperform the same 18".

Oh and FYI, don't look for a subwoofer, or a certain size cone, just because of it's sensitivity. It's one small parameter, not enough to rule out a subwoofer.

[Gioia69 30]

you really think 6 cubes is choking an 18? i have no experience with 18s but that just doesnt seem right. my 15" fi bl is in 4 cubes and i think it does very well for itself and sounds great. and isnt 6 cubes too big for a single 15?

That's almost the MAXIMUM airspace for a 15", that would be why. it's more efficient.

and dont a lot of ppl put 18s in 5 cubes? or are they just stupid? what would YOU consider to be the minimum box size for an 18 without choking it?

It really is stupid to put an 18" in 5 cubes, that's the bare minimum and the maximum airspace for a 15", in that alignment the 15" in the better box would outperform the same 18".

Oh and FYI, don't look for a subwoofer, or a certain size cone, just because of it's sensitivity. It's one small parameter, not enough to rule out a subwoofer.

honestly im not experienced enough to know how the other specs effect a subs performance. Im not super new to all this, but when i read all of the shit some of all u have to say about physics and all that other complicated stuff, id still consider myself a noob. What would u say isn't choking an 18? Too big to fit in a trunk of a grand prix?

edit: I basically chose the BTL because im pretty satisfied with my BL that i currently have right now, and it seems like everyone loves the btl. And for the 6 months of time that ive put reading stuff on all of these audio forums, i really haven't heard a negative thing about the btl yet.

Edited August 21, 2009 by Gioia69

[Duran 387]

you really think 6 cubes is choking an 18? i have no experience with 18s but that just doesnt seem right. my 15" fi bl is in 4 cubes and i think it does very well for itself and sounds great. and isnt 6 cubes too big for a single 15?

That's almost the MAXIMUM airspace for a 15", that would be why. it's more efficient.

and dont a lot of ppl put 18s in 5 cubes? or are they just stupid? what would YOU consider to be the minimum box size for an 18 without choking it?

It really is stupid to put an 18" in 5 cubes, that's the bare minimum and the maximum airspace for a 15", in that alignment the 15" in the better box would outperform the same 18".

Oh and FYI, don't look for a subwoofer, or a certain size cone, just because of it's sensitivity. It's one small parameter, not enough to rule out a subwoofer.

honestly im not experienced enough to know how the other specs effect a subs performance. Im not super new to all this, but when i read all of the shit some of all u have to say about physics and all that other complicated stuff, id still consider myself a noob. What would u say isn't choking an 18? Too big to fit in a trunk of a grand prix?

You can put it in there, but its by far not the smartest option. My personal requirements for an 18" is about 7 cubes, with adequate port area(between 84 and 112 square inches of port) tuned to about 35 Hz. you just can't do that in a trunk. The absolute smallest I would go is 5 cubes and 70-80 square inches of port...and a 15" would outperform the 18" in that same enclosure.

[NB50 206]

Bad plan. You can't fit an 18, you shouldn't even think about impedance rise, and that is more power than you need for a BTL.

idk man. i dont have the pontiac now, but i had one before, it was a '98, so its the same body style as the 02 im gonna get. that definitly has a bigger trunk than my 94 buick regal, and right now i have a box thats exactly 4 cubes after port, driver and mdf displacement. and the only issue was getting it into the trunk, not it fitting. i think i could get a box thats 6 cubes in there after all displacements. and yeah i was planning on tuning it low if i was gonna roll with the 3500 watts. probably not in the 20s, but somewhere between 30 and 33 hz.

Unless your going to build the box in the trunk you will not get it in. The largest box you can do while fitting it through the trunk opening is about 5ft^3 gross volume.

[///M5 2,833]

I go back to saying it won't fit. Can you make it? Yes, will you? I doubt it.

Simple solution. Build the box first, build it as big as you can then measure the volume of it and afterwards cut the baffle for the driver. Picking the sub before the box makes no sense whatsoever.

70lbs really isn't worth worrying about btw.

[Lucky 76 5]

I go back to saying it won't fit. Can you make it? Yes, will you? I doubt it.

Simple solution. Build the box first, build it as big as you can then measure the volume of it and afterwards cut the baffle for the driver. Picking the sub before the box makes no sense whatsoever.

70lbs really isn't worth worrying about btw.

I agree 100% with this. If the box is too small pick another driver that will perform better in that box. If your sub is choked it will not be as loud and it will sound like ass. Not to mention there is the possibility of damaging the subwoofer and amplifier.

Edited August 24, 2009 by Lucky 76