Fi BTL N2 18" Box Help

[jmander11]

I have a 2003 Acura CL with a decent sized trunk, so 4.5 - 6 cubes at the most is manageable to fit in the trunk opening. (Fi says 4.5 - 8 cubes) I'll have to measure the width between the 6x9s because the sub will have to fit between those since they hang down.

Here are the specs for the BTL N2 series:

N218

DUAL 1 | DUAL 2

Fs: 34.0 Hz | 33.6 Hz
Re: 0.7 Ohms/coil | 1.4 Ohms/coil
Qms: 8.18 | 8.28
Qes: .32 | .32
Qts: .31 | .31
Mms: 336g | 344g
Sd: 1210cm^2 | 1210cm^2
Vas: 133.8 l | 133.8 l
Spl: 94.0dB 1W/1m | 93.8dB 1W/1m
Bl: 17.8 N/A | 25.1 N/A
Xmax: 28mm * | 28mm *
Rms: 2000W * | 2000W *
Sealed box: N/A cuft | N/A cuft
Ported box: 4.5-8.0cuft | 4.5-8.0cuft
Sub OD: 18.500” | 18.500”
Cut ID: 16.750” | 16.750”
Mounting depth: 11.125” | 11.125”
Displacement: 0.18cuft | 0.18cuft 

The trunk is fairly long so an 18" will fit comfortably with room for the port. 2 15" drivers are not really an option because the extra weight and size will be too much for my car (front wheel drive) not to mention I will have to spend more on amps, wiring, alternator, etc... So far with a stock battery up front, a second decent battery in the back, and an alpine m-1000 amp there is 0 light dimming. 2 12"s just won't be loud enough or low hitting enough . I'll probably upgrade the stock front battery at the same time I upgrade to new equipment.

I'm not a noob to car audio, yet I'm no expert. I'm 16, but on my 4th system and have upgraded mids/highs with kicker speakers all around amped and currently have a 15" Planet Audio 1500RMS sub that is doing it for now. I've gone through dual 10"s, quadruple 10"s, 1 15" Alpine type R (Great SQ sub I found, just not loud enough)... The thing is, I have become accustomed to the bass and to ME it's like having dual 10" subs again... yet everyone else says their ears hurt etc. etc... lol. So I'm looking at an 18" to keep me satisfied for a while. I can clearly hear the mids/highs over the bass and I can still turn them up more if necessary before clipping when/if I get this 18".

Bottom line, I've heard great things about Fi subs, and a fully loaded Fi N2 18" sub shipped came to around $650ish to Canada if I recall. What I want to know is if this 18" will perform well in a 4.5 - 6 cubic foot enclosure, or if there is a different 18" sub that will perform better in a small enclosure.

I was also wanting to know how would this sub sound, and would it get LOUD?

I appreciate any input, but please don't nag on my age or this being too much bass, I'm ready for it.

Tips on a better sub are welcome, I'm not set on this sub it is just the only one I know of.

Thanks guys!

Edited October 10, 2011 by jmander11

[soundcheck11]

If you can fit a 7.5cuft box in there that would suit you very nicely. These subs are power hungry. Got a friend that has 2 fully loaded and hes running 4.5krms to 2 of them and hes well over 50+ db. His how ever is walled but after port displacement and sub displacement hes at around 7.5. if you cant do 7.5 then build it to as big as your trunk will allow. Would def make it ported! You can get this very loud. Try for a bigger amp then youd be set! I myself am looking at 4 fully loaded btl n2's in either a clamshell or a tunnel.

Good Luck hope this helps alittle

[bkolfo4]

That is 4.5-6 cuft net volume after port and driver displacement.

You need to determine the exact dimensions your box can be and decide if you might be better off going with a 15" driver.

[jmander11]

Ok I measured the trunk, here are the dimensions:

Under 6x9s: 34" wide, 15.5" high, 28" long

Between 6x9s: 22" wide, 17" high, 34" long

That enough?

[pro-rabbit]

Ok I measured the trunk, here are the dimensions:

Under 6x9s: 34" wide, 15.5" high, 28" long

Between 6x9s: 22" wide, 17" high, 34" long

That enough?

Are you wanting to do just a basic enclosure? If so then your "under 6x9" enclosure is the best option. If you want to do something a little different then you can build your "under 6x9" specs then add the between area to it and get a tad bit more space.

Looks like you are going to have to use precision ports or similar though to get the volume you want.

[lem43606]

I have my btl 18s on a powerbass 5k each sub is seeing 6.4 after displacement and port it gets fairly loud according to most ppl but for me they need to be louder and these woofers sound great to me they sound better then the AQs that I had. You wont be let down by the n2s.. but if I were you.. id maybe try and fit 2 btl 12s in your trunk.. more cone area then seal it off!

[Real96SS]

I'm not the expert on boxes but if you put your measurements in the RE calculator you can tweak your specs until you get the volume frequency your looking for. As far as if 6cft will be enough for this sub,that should be enough since FI calls for 4.5 to 8. Here's the link to the RE website for the box calculator

http://reaudio.com/box.php

[lem43606]

I'm not the expert on boxes but if you put your measurements in the RE calculator you can tweak your specs until you get the volume frequency your looking for. As far as if 6cft will be enough for this sub,that should be enough since FI calls for 4.5 to 8. Here's the link to the RE website for the box calculator

http://reaudio.com/box.php

Most ppl on this forum like to use torres box calculator.. and its downloadable

[jmander11]

Ok I measured the trunk, here are the dimensions:Under 6x9s: 34" wide, 15.5" high, 28" longBetween 6x9s: 22" wide, 17" high, 34" longThat enough?

Are you wanting to do just a basic enclosure? If so then your "under 6x9" enclosure is the best option. If you want to do something a little different then you can build your "under 6x9" specs then add the between area to it and get a tad bit more space.Looks like you are going to have to use precision ports or similar though to get the volume you want.

Yes, just a basic one. I'll make it under the 6x9s then.

I have my btl 18s on a powerbass 5k each sub is seeing 6.4 after displacement and port it gets fairly loud according to most ppl but for me they need to be louder and these woofers sound great to me they sound better then the AQs that I had. You wont be let down by the n2s.. but if I were you.. id maybe try and fit 2 btl 12s in your trunk.. more cone area then seal it off!

That's good news. If I were to fit 2 in though then I would need minimum 4K RMS.. And a lot of upgrades would have to be done. Basically that's just a hassle... And last time I checked 1 18" was more cone area than 2 12"s?

How would the sub do from 5 to 6 cubes after displacement?

I'm not the expert on boxes but if you put your measurements in the RE calculator you can tweak your specs until you get the volume frequency your looking for. As far as if 6cft will be enough for this sub,that should be enough since FI calls for 4.5 to 8. Here's the link to the RE website for the box calculatorhttp://reaudio.com/box.php

Most ppl on this forum like to use torres box calculator.. and its downloadable

I have Linux so web calculators are fine

P.S. I listen to music like rock, rap, and dubstep mostly... So what would be a good tuning? I want the sub to hit down to 32hz on Get Back by Ludacris. So what tuning would you guys recommend? 30-32?

[Real96SS]

Yeah I tried using the torres one but the RE one was alot easier for me.Im new to the box designing scene so don't think I'm saying one is better than the other. I just found the RE calc to be a tad bit easier to use for my level.I still can't actually get my specs done for my box until my truck arrives so for now I'm using the specs off motor trends for the bed and midgate area.