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Ok , my b-day is coming up on the 24th and my dad is going to give me some money so i can buy a sub. I am going to get a 4+4 ohm kicker compvr 15". My friend is giving me his old amp, a bazooka el1500(i know, but better than nothing). It does 500 rms at 2 ohms, but don't have a subsonic filter. I was wanting a big ported box, but what if i only do a single sealed box, how much of a difference will it be? I plan on eventually getting one more and putting them both on a bx1000d in the future and it has a ss. So i guess my main question is can i buy a external type subsonic filter? like that the wires go through? Also what will be the difference b/w the large ported box and the sealed box? you think this is going to be ok? sound good? loud?

Btw, im hooking it to a sony cdx-m610(
decent deck)

 
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I have an Infinity 10" inside sealed box and it's more than enough bass for me.

 
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Sealed box should sound fine as long as the dimensions match for air! If not it will sounds distorted and even blow (or so I was told) anyhow good luck!

 
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no worries about the subsonic filter. its the sprinkles on the ice cream, not the meat and potatoes of the meal.

500 rms is plenty for a comp VR, large ported, or small sealed, sounds like a good setup to me!

 
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So the subsonic filter is no big deal? I heard that if your sub tries to play a subsonic frequency below the port frequency, that it will blow. I don't wanna blow my sub. Just want to make sure it will be ok. I plan on running the el1500 for about a month, until i get some money for the bx1000d, then i will run the bx1000d at 2 ohms until i save up for another compvr, then put them in a dual ported enclosure running 1 ohm. I really want to port this thing but don't wanna blow it. Everyone on here and sd says it is a night and day difference. Do you think i will be able to hear this over my front speakers(sony 3-ways on a rockford 200s) when i turn the bass up? ANd one last thing, is a 4 gauge amp kit enough for the el1500 and bx1000d? the wires i plan on getting are from knukonceptz, is this company any good? Sorry for all the questions, but this is my frist system, and im doing this all myself. And in case your wondering about me having to save up a month or two for a bx1000d, it is because im only 15 and have no job Anyway, thanks for all the help

 
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ive heard htat if you put a subwoofer in a box wiht fresh silicone applied, the silicone fumes will melt the surrounds.

ive heard that adding a big capacitor into my car will audibly improve the sound quality of my vehicle, then these same people tell me swapping the amps will make no difference in the sound.

ive heard that three layers of fiberglass is plenty of thickness for a glass box, with no a priori knowledge of the type of glass used.

ive heard you need a new alternator with a 500 rms amp.

ive heard lots of things, and one of htem definitely is "no subsonic filter + ported box = blown woofer."

equipment doesnt blow itself, tuning does.

if you decide to put your comp VR's in a huge huge box ported to 50 Hz then play music with 30 Hz tones, then crank the gain on the amp, then crank the volume on the radio, of course its gonna blow the woofer!

realistically, its not an issue in the daily driver car audio world. so why does it happen so often? give a little kid a little bird, and he will squeeze it to death, shatter its skeleton, then cry that the bird is broken. these guys build pisspoor boxes, play them way too loud, crank the gains, are pissed its not loud enough, turn on the bass boosts on their amplifiers and radio's, and blame the blowout on not having a subsonic filter.

ever wonder why this crybaby bandwagon started with the death of the JBL BP amplifiers and the unveiling of the Hifonics Brutus series class D amplifiers? makes me wonder....

as for your case, with the comp VR, 500 rms is PLENTY to achieve full excursion and blow the woofer too, even in 1.8 cubes sealed! so you will have to be responsible about tuning no matter what, with that amount of power.

if you want to increase your low frequency extension, dont worry about a ported box, you will jsut as likely blow the woofer in the ported box than the sealed! this isnt to say the equipment is bad, I think you made some good choices! The point I want to get across is that in your situation, the ported box doesnt make it any more likely you will blow hte woofer than sealed. Unless you tune to 50 Hz, i dont think youd do that.

in a box tuned in the low 30's high 20's, youd be fine with no subsonic filter.

as for tuning, my basic rule of thumb is if I cant hear distortion, I wont blow the woofer. as long as you dont entertain yourself by opening the trunk and throwing pennies at the woofer at full volume (I am not kidding this has happened) then you should be fine.

even with a single comp VR youve got plenty of bass to match up to your xplods, so no worries there!

as for wiring, I think you are on the endge of whats a good idea. I think you would be far better off with 2 gauge wiring as opposed to 4 gauge, and its not too much mroe expensive.

knu is great wire, I bought the stuff four years ago and the only cheap wire I like better is audiopipe.

good luck with your stereo, keep with it and youll be a pro before you know it!

 
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OK thanks alot for the help. I plan on building the box on the kicker website. 5cubes tuned to 30hz, will this get loud? there is one thing that concerns me, on the plans for the box it says power handling: 500rms with 25hz subsonic filter set at 24/db octave. Without subsonic filter 300rms. What is the 24/db octave? And are you sure about the ss? I really want to have the port on the front of the box, but the kicker website has it on the side, if i keep the same dimensions, can i just move it? I was planning on a box where the sub is in the middle and has two smaller slot ports on each side, is there any problem with this and do you know where i could find plans for it?

 
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Also, i don't think im going to be turning all the gains up and stuff. I am going to use the tutorial on the jl website for setting the gains and just leave it there. And i do believe everything you say whiterabbit, since your the car audio god on here, but i really want to play it safe and have a subsonic filter, do you know of any i can just buy that are universal, like that the rca's plug into?

 
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you can get f-mods from partsexpress, youll need two sets if you want a 24 dB slope. thats a $50 investment just for a subsonic filter.

at 5 cubes per speaker, I can believe that kicker would be concerned about making sure they spec a subsonic filter.

but if you follow the JL tutorial for gain setting, chances are the bass is gonna be so quiet youll never have to woryr about blowing them, subsonic filter or no.

if you insist on a SS filter, a pair of f-mods inline with each other will do it.

 
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OK, you talk like i don;t need it and i don't wanna spend $50 if i don't have to. I am going to build box at 5 cubes, but what about the port being on the front? or two smaller ports on each side? will it work like this? I don't want to make it a big deal with the two front ports. I am mainly concerned about making the side port into a front port, if i keep the same port length, would the tuning be the same? also, do you think the 30hz tuning is good? I mainly want spl

 
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for spl, id keep 30 Hz. you can get more dB at higher tunes, but music would sound like junk, and now youve increased the number of frequencies playing that make the subwoofer unload (youve heard this before as "playing under the tuning frequency"). in fact, for the kind of music popular today for impressive bass driven systems, tuning lower has had some pretty good results. your woofer will increase in LFE, youll actually lose metered dB's but the lower frequencies can get pretty impressive.

for your needs, however, tuning at 30 Hz should be jsut about ideal.

you cal totally port out the front and be fine. as long as the port area and length are the same, you're set!

remember, just because you dont NEED a SSF doesnt mean you cant blow them! it just means tune responsibly, and youll have no issues! just a friendly reminder, but if you follow the JL instructions, you shouldnt even get close to blowing it out. if it sounds healthy, you are ok!

 
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Ok thanks alot for the help whiterabbit. I'll keep it at 30hz and listen real careful for clipping. I understand what you are saying about the gains, i'll keep it down and be careful. I think im going to lowes tomoroow to get some mdf,plexiglass, and other materials. Im going to build a face to the box that fits the contour of the edges of the trunk and raise the floor to put the amp under plexiglass in the middle of the floor with a blue neon on it. i will be sure to post some pics when complete.

 
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Can i change the port width, but make it longer to maintain the same port volume? will this work, b/c kickers port on the box is the same length from the front to back of the box. so instead of the port being 3 in. wide, can i make it 2" and increase the port lenght to maintain the same volume, while keeping it at 30hz?

 
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port tuning is based on three numbers:

port crossectional area
port length
box volume (NOT including the space taken up by the woofer or the port!)

so you dont need to worry about port volume, if kicker spec is a 3"x8" port, you can make yours 2"x12", 4"x6", or any combination you want, as long as its the same crossectional area. this allows you to keep the same length at the same box volume to keep the same tuning.

If you want to change the amount of port area, while keepingthe same box volume and tuning, you can jump on JL's website and go to the port tutorial, youll find the govorning equation to find out how long your port needs to be to achieve a 30 Hz tune with 5 cubic feet of box with X amount (your desired amount) of port area.

also check out the tutorial on bending ports, if you dont already know about bending ports, its a neat idea to know about when building ported boxes!

 
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well thats my problem, the port length. The port length is the same as the width of the box from front to back, so the port on the kicker website is 3 x 15 1/2", can i make it like 4 x 15 1/2" and make it shorter so it would be shorter than the width or with it be better if i made the port like 2 x 15 1/2" and made it longer, so it makes a 90 degree corner around the back of the box? the length of the port on the website on the cut sheet is 21 1/4", but after adding in an extra 3/4" for the outside mdf thickness it comes to a port that is 3" x 15 1/2" that is 22" long. So the length is what needs to change. i was thinking more like a port that is 4" x 15 1/2" that is shorter, is there any minimum length for a port? I just dont know how long to make it?

 
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That ed enclosure looks good, but i want a 5 cubic foot box for deeper bass.

 
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nope, no minimum length. I would make sure its large enough in port area not to cause severe port noise. you can make a port .75 inches long and jsut cut a hole in the side of the box, but that port area would be tiny to keep teh same tuning frequency! it would more likely than not act like a sealed box with a breach!

if you want to make a smaller length port, get on JL's site and use the port equation. input the boxvolume, the tuning frequency, and the desired port length to see how much area you need to achieve that tune. you can do it on winISD too

 
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the ED enclosure is for ED subwoofers. I included it to demopnstrate how to bend ports, not to suggest it for use to build. you dont even need a 90 degree bend, you can jsut snake it back and forth like that!

 
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thanks for the help, I think im going to make 4" x 15.5" port that is longer and make an L at the back of the box. I'll figure it out, but now that i read the tutorial, i think im going to do two slot ports, one on each side, for apperence.