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View Full Version : need a recommendation for an 18" woofer in a 4ft box



POS carb
07-20-2012, 02:10 PM
Yea, I am going to try dual 18s in the police car.
It currently has a sealed box with 3.9 ft internal per box (7.8 total). I don't want to build another box.
I want an 18" that will play deep and loud, preferably a low-mass cone, like they use in pro audio or home applications. I can always add a port tube or reduce the internal volume. I want it tuned to at least 30hz if ported. I have plenty of power, just trying to work with the box I have. I could also modify it to a single 7.8 ft box but I would really prefer to keep it a dual 3.9ft box.

So, in short, I need a recommendation for an efficient 18" that works in a 4 ft box, sealed or ported, under $200 per sub.

The 15's I had in it were stupid loud but the tinsel leads ripped out of the coil (they were designed for a much smaller box and got too much xmax, they were also heavy cones so not very efficient)

http://carphotos3.cardomain.com/images/0015/54/10/15874501_large.jpg

charliekuney
07-21-2012, 12:35 AM
Oh my fuck.

RAZR
07-21-2012, 07:57 AM
:facepalm:

Why do you want a 18 inch sub?
I have a 10 inch kicker CVR sub in a sealed box and a Kicker 600.4 amp. If i crank the bass on my head unit i can shake the whole car. Why do u want something so big?

POS carb
07-21-2012, 12:43 PM
I've always wanted a stupid loud system. I used to DJ and my house is full of big speakers so my idea of loud enough is probably unreasonable to you.
I don't need 800hp, 300 is enough, but it would be fun to have on tap.

I've always wanted to do a system with some 18s, I've had 12s and 15s.
I'm not looking for SQ in this car, just to annoy my neighbors and do hair tricks and play subharmonics :)

I'm a bit of a big speaker nut
In my room:
Cornwall 15's
http://carphotos2.cardomain.com/images/0015/65/84/15875648_large.jpg

and these are the surrounds
http://carphotos4.cardomain.com/images/0015/65/94/15875649_large.jpg


In my dining room:
Klipsch K-horns (15's of course)
http://carphotos4.cardomain.com/images/0015/65/05/15875650_large.jpg


In my spare room:
MTX DJ speakers
http://carphotos2.cardomain.com/images/0015/65/64/15875646_large.jpg


In my garage:
Custom Kicker 5x7 and Cerwin Vega tweeters
http://carphotos3.cardomain.com/images/0015/65/74/15875647_large.jpg



In the 3gee:
http://carphotos.cardomain.com/ride_images/1/3036/2781/7588890065_large.jpg
took these out and put them in the Vic and proceeded to rip them to pieces. Replaced them with JBL 15s

POS carb
07-21-2012, 12:52 PM
Oh my fuck.

:bowrofl:

but seriously, I am unreasonable and all, I still need a recommendation.

This is what I have in mind:

http://www.parts-express.com/images/item_standard/295-036_s.jpg

http://www.parts-express.com/wizards/searchResults.cfm?srchExt=CAT&srchCat=583

RAZR
07-21-2012, 05:50 PM
Well if you going for SPL you dont stupid big speakers.
http://www.youtube.com/watch?v=8isMS8a1vMU
This^right here shows that you dont need crazy power and huge subs. It all comes down to your box design and build quality.

Vanilla Sky
07-22-2012, 12:48 AM
How much power are you going to be working with? Do you want something that extends down to about 30hz at -3dB or so, or do you mind making up for low end with more power?

POS carb
07-22-2012, 05:46 AM
Well if you going for SPL you dont stupid big speakers.
http://www.youtube.com/watch?v=8isMS8a1vMU
This^right here shows that you dont need crazy power and huge subs. It all comes down to your box design and build quality.

I know, but the box is built and I do not want to build another box
I am just looking to replace the 15's I killed



How much power are you going to be working with? Do you want something that extends down to about 30hz at -3dB or so, or do you mind making up for low end with more power?

Plenty of power
500 rms x1 @ 4 ohms @0.1% THD
1000 rms x1 @2 ohms
1500 rms x1 @1 ohm

Amp also has a variable subsonic filter of 15-35hz if I go ported

Vanilla Sky
07-22-2012, 04:37 PM
Are you going to be running the subs in stereo or mono wired together? How much are you looking to spend, and while I know you mentioned wanting to belch out some killer sub-harmonics, how low do you want to go? I've run into more than one driver that will theoretically bottom out in the 40hz range in your current enclosure given the power you have.

Have you played with any enclosure simulator programs? That's how I pick my drivers.

POS carb
07-24-2012, 05:55 AM
u don't RTFA lol

it's a mono amp
500 rms x1 @ 4 ohms @0.1% THD
1000 rms x1 @2 ohms
1500 rms x1 @1 ohm

I need a recommendation for an efficient 18" that works in a 4 ft box, sealed or ported, under $200 per sub.

I can always add a port tube or reduce the internal volume. I want it tuned to at least 30hz if ported. I have plenty of power, just trying to work with the box I have. I could also modify it to a single 7.8 ft box but I would really prefer to keep it a dual 3.9ft box.


right now I'm leaning towards this one:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-475

SPECS: http://www.parts-express.com/pdf/295-475s.pdf

Power handling: 300 watts RMS/450 watts max • VCdia: 3" • Le: 2.96 mH • Impedance: 4 ohms • Re: 3.2 ohms • Frequency range: 22-500 Hz • Fs: 25 Hz • SPL: 94 dB 2.83V/1m, 91 dB 1W/1m • Vas: 9.90 cu. ft. • Qms: 5.64 • Qes: 0.51 • Qts: 0.47 • Xmax: 8.25 mm • Dimensions: Overall diameter: 18", Cutout diameter: 17", Depth: 6-7/8".

Vanilla Sky
07-24-2012, 05:39 PM
I've done up a few, and that model of sub requires more box than you have space for to get any decent response under about 40hz. It drops off very fast, -3dB at about 42hz and -6dB at 36hz, and -12dB at about 24hz.

As a single sub, it wants about 8.5 cubic feet in a sealed enclosure, and almost 19 cubic feet with a tuning of around 20hz.

At 500 watts per sub, and assuming full power, you are in danger of exceeding xmax around 60 hz.

Right now, I'm trying to look at drivers that work well in your enclosure. I'm having trouble finding anything that really shines down low. It seems like most of the 18" drivers on the market are closer to full range drivers than subs.

POS carb
07-25-2012, 04:57 AM
what are you using to model this? I'd like to try some different specs out. Hell I I may stick with a pair of 15s

POS carb
07-25-2012, 12:08 PM
Well looks like I'll be sticking with a 15 on this box

this is what I have in mind, let me know if your software agrees

==============================================

box is 3.9 ft internal. should have good response, about -3 @30hz
for sealed:

RSS390HF-4
Specifications: • Power handling: 500 watts RMS/800 watts max • VCdia: 2-1/2" • Le: 1.00 mH • Impedance: 4 ohms • Re: 3.3 ohms • Frequency range: 18 - 800 Hz • Fs: 18 Hz • Magnet weight: 150 oz. • SPL: 90 dB 2.83 V/1m, 87 dB 1W/1m • Vas: 9.95 cu. ft. • Qms: 3.10 • Qes: 0.49 • Qts: 0.42 • Xmax: 14 mm • Dimensions: Overall diameter: 15-5/16", Cutout diameter: 14-1/8", Depth: 6-5/8".


================================================== ==============


for ported. box is 3.9 ft internal. port 4" ID 11.31" L fb 25hz
should have good response all the way down to 25hz

RSS390HO-4
Power handling: 800 watts RMS/1400 watts max • VCdia: 2-1/2" • Le: 1.83 mH • Impedance: 4 ohms • Re: 3.3 ohms • Frequency range: 21 - 600 Hz • Fs: 24.2 Hz • Magnet weight: 150 oz. • SPL: 90 dB 2.83 V/1m, 87 dB 1W/1m • Vas: 3.87 cu. ft. • Qms: 4.48 • Qes: 0.42 • Qts: 0.39 • Xmax: 12 mm • Dimensions: Overall diameter: 15-5/16", Cutout diameter: 14-1/8", Depth: 6-1/8".


if you get a chance I'd like to know if your software agrees

DBMaster
07-25-2012, 01:45 PM
Eric, how is it to drive that police car? Is it like Elwood Blues said, "Cop motor, cop tires, cop shocks...?"

POS carb
07-25-2012, 02:33 PM
I barely drive it but when I get in it i have the seat reclined, i drive like a grandmother, and steer with my thumb. It's freaking massive, i feel like i'm driving my living room.
I saw one on craigslist and the seller had the audacity to say "it handles like a honda"
Really it handles like a 3gee with another 3gee on the roof. It can get sideways but there's something wrong with it, it has no top end at all, I think the fuel filter may need to be changed. Also, some dick replaced the cop rearend with a stock rearend , i think it's 2.73 or some ridiculous ratio and no limited slip. :(
Cop shocks and cop brakes are shot, I have the parts in my garage, they've been sitting there for like 2 months :lol:
I had bass to piss off the cops too, but those subs were so old I destroyed them when I put them in that huge box. They were in the 3gee for over 5 years, in the vic I maxed out a 130dB meter, I have no idea how loud they went but I'll bet the right woofer will really pound in there. The transfer gain in that car is probably like an SUV

Vanilla Sky
07-25-2012, 06:37 PM
The first woofer there with a single 29.5" long, 4" port on each side would tune the enclosures to about 16hz would be excellent. Back the gains down a little bit, and you wouldn't have a problem exceeding xmax, either. Not accounting for cabin gain, you'd be hitting about 115dB. I'd expect it to have about the same cabin gain as an extended cab mini truck with a ported wall and the box in the bed.

With the second sub, you just about need to port it. It's not as much of an issue fitting it, as it's only going to need a single 14" port in each chamber. That tunes the box to about 25hz. Good response down to 25hz.

Some graphics:

http://img.photobucket.com/albums/v234/wannabe_otaku/Subs.png

Green line is sub one, grey line is sub 2. Spot on recommendations.

POS carb
07-26-2012, 06:16 AM
I gotta try that program, looks a little nicer than the online calculators I was using

What would you choose?

for sub #1 I was thinking sealed (EBP=36.7), do you think ported would produce better results in the trunk? with sealed I was seeing only -3db at 30hz which is way better than I was getting with the old subs.

If I port it I think I'll be going with sub #2

remember, the interior space and trunk volume in this vehicle is huge so cabin cabin is probably on the lower frequency range

Vanilla Sky
07-26-2012, 12:31 PM
Both would be good choices in a vented enclosure, but I'd avoid putting the second one in the enclosure without porting it. The neither sub lists mechanical limits, so I'm not sure if you're going to be in danger of bottoming anything out or tearing anything, but every Dayton Audio driver I've ever played with seemed to be built well and expected to be pushed hard.

I think I'd go with the first sub, the HF model. The second sub will be slightly louder, but the first sub doesn't taper off under the curve as much and doesn't unload until it gets under the tuning of that box, which is 16hz. Theoretically, you'll exceed xmax between 25hz and 35hz, but won't do it again until under 14hz. The second sub becomes almost hopelessly unusable under about 20hz, even though there's not much down there in most music.

Unless I'm looking for a small enclosure, I tend to stick to ported enclosures. I'm usually working with an unlimited amount of enclosure space, though, since I normally build home audio speakers.

lostforawhile
07-26-2012, 02:13 PM
Eric, how is it to drive that police car? Is it like Elwood Blues said, "Cop motor, cop tires, cop shocks...?"

probably like driving my 90 towncar, it's also based on the panther platform, towncar,crown vic, and mercury marquis you don't drive these cars, they float lol

lostforawhile
07-26-2012, 02:14 PM
I barely drive it but when I get in it i have the seat reclined, i drive like a grandmother, and steer with my thumb. It's freaking massive, i feel like i'm driving my living room.
I saw one on craigslist and the seller had the audacity to say "it handles like a honda"
Really it handles like a 3gee with another 3gee on the roof. It can get sideways but there's something wrong with it, it has no top end at all, I think the fuel filter may need to be changed. Also, some dick replaced the cop rearend with a stock rearend , i think it's 2.73 or some ridiculous ratio and no limited slip. :(
Cop shocks and cop brakes are shot, I have the parts in my garage, they've been sitting there for like 2 months :lol:
I had bass to piss off the cops too, but those subs were so old I destroyed them when I put them in that huge box. They were in the 3gee for over 5 years, in the vic I maxed out a 130dB meter, I have no idea how loud they went but I'll bet the right woofer will really pound in there. The transfer gain in that car is probably like an SUV
they don't have any top end, the torque is all setup low in the power band, is yours the 5.0?, I assume the police car has the dual exhausts? Ford did the dumbest ass thing I've ever seen, they ran dual exhaust up to and including dual converters, then ran the pipe over to the other side and made it a single, I need to fix it, it's a proven 20 hp and 15 foot pound of torque gain going back to the dual, the 89 had the same 5.0 and it had duals so WTF were they thinking? if you have the 5.0 check your TPS, I have the same issue, sometimes it will haul ass like it's on fire and sometimes it's a slug, I get an intermittent TPS code

POS carb
07-26-2012, 02:59 PM
If I add a port to this box, am I supposed to subtract the port tube volume from the volume of the box when performing my calculations?

I'd like to see some of your diy projects. got any pics?

I think I'll be going with sub #2 in the 25hz box, I have a subsonic filter on the amp to cut the lows

POS carb
07-26-2012, 03:02 PM
it's a 4.6, a 95, that's the last year they came with the metal intake. previous owner was an idiot and ruined the car, that's why I got it so cheap. I get an egr insufficient flow code ever since I washed the engine lol but it was just as slow before. also, the fan clutch is jammed on maximum

lostforawhile
07-26-2012, 05:55 PM
it's a 4.6, a 95, that's the last year they came with the metal intake. previous owner was an idiot and ruined the car, that's why I got it so cheap. I get an egr insufficient flow code ever since I washed the engine lol but it was just as slow before. also, the fan clutch is jammed on maximum

I don't know much about the modular engines, mine has the old pushrod 5.0 in it, last year for it, i can see if i can find a fan clutch the next time I go to the yard, they usually have a bunch of those engines

Vanilla Sky
07-27-2012, 02:31 AM
I wish I had pictures of my old stuff, but the laptop I had most of my pictures on was stolen. I've sold everything off in an attempt to regain some storage space. Enclosures are huge :p

POS carb
07-27-2012, 04:33 AM
I don't know much about the modular engines, mine has the old pushrod 5.0 in it, last year for it, i can see if i can find a fan clutch the next time I go to the yard, they usually have a bunch of those engines


I can get a fan clutch, I just don't want to put money into this car, I'm going to sell it when I get my Mustang finished. Car stays cool so it's staying that way. I doubt most buyers will notice

2oodoor
07-30-2012, 03:10 PM
I can get a fan clutch, I just don't want to put money into this car, I'm going to sell it when I get my Mustang finished. Car stays cool so it's staying that way. I doubt most buyers will notice

Doesn't that car have both electric fan and belt driven clutch fan? i know they had them in 96. It is important to pull off the plastic cover over the radiator support and clean out the unbelievable amount of crap that gets caught in between the condensor and radiator. Ive seem them completley stopped up with grass and caked up chunks of who know what it was.
LOL and they didn't start handling "like a Honda" until around 2003. Redesigned front suspension with rack and pinion, aluminum control arms, 17 inch wheels...
did yours stil have a cage in it? You just about could make the whole rear cabin a sub box:thumbup: