PhLaXuS

**This is long, but please read it if you don't mind**

OK...I've been sorting out various problems with this entire purchase/install and I think I've actually eliminated all the other problems. Here's the setup:

Kicker KX1200.1 running into two Solobaric L7's. Total load is wired for 1 Ohm. The birth sheet on the amp states 1470W. Everything is wired properly (& in phase). The box consists of two chambers built to Kicker's spec of 0.88 cubic feet each and they are ~1/2 filled with PolyFil. The walls are 1" MDF.

So here goes: The bass section of my previous system consisted of two 10" Kicker CVR's in a sealed box. I had folded the rear seats down and sat the box on top of them and aimed it toward the rear. This setup (only 260W) hit pretty frickin hard and sounded all right. Problem is the new setup plays lower, but doesn't hit much better than the old one.

I could accept this if I bought a comparable system, but the new one has over 5x the power of the old and has about 1.8x the cone area. The box has been checked and appears airtight (& I cut the carpet from around the sub gaskets just to be sure). The only functional change I can find between my old & new system is:

1.) The sub box is in the same spot as the old one, but now facing forward instead of toward the rear; as the old system did
2.) The drivers themselves (S12L7) I'm certain play a huge part in this.
3.) The old amp (1998 model Kicker Impulse) had the LP crossover set @ I believe 90Hz and the slope was 24dB/octave, IIRC. The new amp is set for ~60Hz and I think it's a 12dB octave slope.

Now, I know Jim85IROC, 1meanGTA, et al. stated that these aren't the best subs (and ESPECIALLY sealed), but by the time I heard this, I'd already bought them. What it comes down to now is that the amp gains are set properly and the subs do sound all right to a certain point. If I'm cruising down the turnpike and crank the system up, it looks (and sounds) like I'm hitting the xmax of the subs. It makes this TOTALLY INTOLERABLE "frapping" noise and I turn it back down. I know I cannot be hitting the advertised 750W RMS/each rating of these drivers, but they sound as though I am, in fact, exceeding the ratings.

I know facing the subs toward the rear will increase the perceived bass, but also make it a bit out of phase. I'll deal with that if I have to, but I'd prefer to stay away from that solution. I know a slot ported box will allow for more output at lower power levels, but will I further lose cone control & negate any gains from the porting? I value SQ and I know these aren't the best SQ subs, but I also love SPL. Where I stand right now, they can't sound much worse, so what do you guys think the best route is to get higher SPL (at the same time probably helping SQ as well)? I'm leaning toward a ported box in the well. Good idea?

Gummie

You might be experienceing some problems with box location, but it shouldn't impact how hard something that size hits as compaired to what you were orginally running.

https://www.thirdgen.org/techbb2/sho...hlight=physics

For the life of me, I can't find the thread that Jim refrences in that post even though I tried searching for it

justlearning

u said that the box is .88 per chamber that is factoring in the displacement of the sub and other obstructions on the inside correct?...as far as that sound your hearing im thinking that they still arent broke in all the way cause it takes these subs a very long time to start to get limber so to speak...my friends took a month or more before u could really start to feel them shake. id say if you try and press on them they will still be very stiff. i too have these subs and yet to install them but i dont think i will be dissapointed cause i know a couple of people w/ just one and it sounds damn good for just one 12.
John

Jim85IROC

iTrader: (2)

Hmm. Those subs in that little tiny box should boom HARD around 50-70hz, and due to the very small enclosure, you should have excellent power handling. Are you 100% sure that the subs aren't out of phase with each other?

PhLaXuS

Most definitely. This was one of the first things I double-checked. I bought a bag of PolyFil from Wal-Mart a few weeks ago and when I was inside the box, I checked the wiring once again. All four 4Ù voice coils are in parallel and in phase. At the amp, everything's cool, too. Watching them hit, it's pretty obvious that they are in phase as well. The excursion looks the same on both subs at all power levels so they are similarly sealed in each chamber. This weekend, just for fun, yeah, right! I'll turn the box around, but it weighs ~140lbs so it's gonna be an evil day.

They are much louder at ~70Hz -- this, I believe, is what was sucking all the power out of my electrical system. I had preliminarily set the LP xover on the amp for ~90Hz to start off while I set gains and such and due to the electrical problems left it like that for a short time. On hard hits in that range, my system voltage would drop to something insane like 10.5V with the engine on. It would occassionally kill the engine. I didn't notice until I re-read the KX1200.1 docs that it was a 12dB/octave LP slope. I was probably playing all the way up to ~200Hz. I set it lower when I discovered that the slope wasn't 24dB/octave like the old amp. Doing this seems so far to have solved the strange low voltage problem.

Jim, if I get around to designing a slot ported box, would you mind looking it over quickly to let me know if it looks OK? If I go this route, I want to do something with an unconventional geometry, but still follow all the rules of ported enclosures.

My neighbor has an SUV with two cheap subs in a slot ported box with 1600W and it will make you unable to see when he turns it halfway up. I know the length/shape/size of the vehicle plays a gigantic role, but it's insane. He even admits that this is a knock-off amp which he'd be lucky if it even put out 1400W.

Jim85IROC

iTrader: (2)

you'll never be able to "see" if woofers are in phase. They move far faster than the eye can detect, even at low frequencies. With all 4 coils, even if it looks right, there's always the possibility that something's botched up.

Start your diagnosis with hooking 1 woofer at a time to the amp, leaving the other one completely disconnected. Does 1 woofer get louder than the 2 used to? Do each of them reach the same loudness? If no to either of these, you've probably got something backwards. More than once I've wired the coils on a DVC sub out of phase, and yet when I played them, it seemed like the high bass (70hz) still sounded pretty normal, but the lowest bass was very thin... exactly what you're describing. This would also explain why you're reaching x-max, getting funny noises, and no bass.

PhLaXuS

I did verify the wiring, but I've nothing against checking again. Assuming the wiring's correct, any clue where to go after that?

Jim85IROC

iTrader: (2)

It's hard to say. There really aren't any other situations that will cause low output dispite the subs reaching their apparent x-max, unless you're grossly overdriving the amplifier, but unless you've got your gain extremely screwed up, I doubt that's the case.

If checking your wiring doesn't turn out to show anything, disconnect all of it and touch a 9-volt battery to the 2 sets of terminals, 1 at a time. Put the + side of the battery to the + terminal and verify that it makes the cone come up (as opposed to sink in) on each coil. I've seen subs have the polarity of the terminals mis-marked, although never on something of respectable quality like a Kicker.

I remember that when I wired those DVCs wrong, I checked and rechecked them and still never realized that I had them backwards. One of the guys I worked with had to check them, then point and laugh at me for 2 weeks. Sometimes when you check your own work, no matter how thorough you think you're being, you can miss something totally obvious.

1meanGTA

i never said that they were bad subs, just that the sound quality wasnt the best. spl wise, they're awesome subs, especially ported. as for them reaching their xmax, how much do you have the amp turned up? that amp is rated at 1200x1 @ 1 ohm right? i know kickers are pretty underrated so its probably more like 1400x1 if you can get 13.5 volts to it.

this does NOT mean you can get 700 watts on each of your speakers. i wouldnt turn the amp up more than 3/4 of the way. do you know how to set your gains with a multimeter? basically when you turn an amp up too much, which is usually past 3/4, it will clip, which basically means it sends a power spike to the sub. im not sure exactly how this works, but i've heard that it sends dc power to the subs. amp outputs should always send ac power. if you look at the signal with an oscilloscope, instead of normal peaks, it will hit the top of the scope and flatten out for a second, like a plateau. this is not good stuff.

i've also heard that the l7's and solos in general take forever to break in. i would try setting the crossover a bit higher than 60, i usually keep my sub xovers at 80 hz. try turning the box around, and if it sounds like its out of phase, you can flip the polarity of the speakers by hooking up the + from the box to the - on the amp and vise versa. my subs are hooked up like this, and they're a bit louder than they were + to + and - to -. you won't do any damage to them this way.

justlearning

u mean hooking them up in series....ive always thought to only do that when your amp dosent have enought power to give the subs adiquite power. i ran mine in parelell when i have enough power and this is how i plan to run my l7s on an mtx 81000d amp. i will need a bigger alternator though i do belive cause im running a 5 farad cap and i still drain my bat to where the acc. will cut out and thats w/ the gain set at less than 1/2 way. i was gonna upgrade the power and ground wire but the alt. wire for stock goes into a fusible link and thats a big bottle neck but im affraid to remove it and the alt. short and draw current and cause an eletricle fire. but id say even w/ upgraded wire it still wouldnt do the job cause its a stock alt. so id say the brushes and all the other parts of it have had it just about and its not worth rebuilding it. but enough ramblin.
John

PhLaXuS

Right now, the amp gain is set to ~5/8. With the head completely flat (sub out gain, master volume settings, etc all set to 0), and no bass boost on the amp, I can run about 25 of 50 on the head's volume controls before this "frapping" noise begins to show up. I've toyed around with it as well such as setting the gain higher on the amp and running the head @ 15-20 and lowering the gain and running the head higher. No matter what I do at a certain point, it sounds like crap.

I was going to check the signal waveform on the oscilloscope here at work to see when the head started to clip/break up, but a few days before I'd set out to do this, my boss sold the scope to one of our contract engineers. Huh!?! We use that thing...stupid decision...

As for the break-in: I listen to these things a minimum of about 25 minutes a day at a decent volume (and with time I've been turning them up more to help further break them in). The system's been in since Sept 17th so I expect that any break-in should be finished.

1meanGTA

no thats just reversing the polarity. series is basically when you take 2 dvc speakers, you connect one of each ones coils to each other, - to - and + to +, then on the other voice coil on each one, you connect the two terminals. heres a diagram.



trust me, take the time to do your underhood wiring. caps are worthless, i guarantee you'll see 10 times the difference you saw from doing the cap from doing the underhood wiring, if you even saw a difference with it. dont worry about the fuse in the alternator wire, leave that wire there. put the 4 or 1/0 gauge wire in addition to the factory wiring, but leave the factory stuff all there. believe me, it'll help your charging problems a lot.

justlearning

yeah i just didnt read your post good i thought u meant just running them in series...as for the wiring underhood if i leave one wire unfuse and one fused wouldnt the unfused wire still allow current draw and allow an electrical fire in worst case senario? what amp fuse would i have to put inline to protect that cause if i put a 100 amp fuse on a 95 amp alt. then it wouldnt protect it i wouldnt think cause it will still let that 95 through it and if i put a 90 i would think the fuse would constantly blow?

PhLaXuS

EE's correct me if I'm wrong, but I think the best way to select a fuse rating is to multiply the expected current draw by 1.5 and run with that figure as long as it is below the rating for the wire.

So a 90A alt would have 135A fuse (let's say 140A to be more rounded), but you'd have to make certain the run of wire could support 140A current draw without becoming unacceptably heated.

There's also other considerations (such as Slow-Blow). For instance, I had a system years ago which required a 60A fuse. The simple addition of a 1.5F cap caused it to pop on hard bass transients and I had to jump up to an 80A fuse. A Slow-Blow 60A would have probably worked but they're not too easy to find in the packaging I had at the time.

1meanGTA

i believe you want to use just under the rated amperage for the wire. i dont know about 4 gauge but 1/0 gauge is rated for 350 amps, i use 250 amp fuses on my 1/0 wires.

justlearning

i have some two guage power and ground wire i got from advance i was gonna go get some 0 guage wire from my speaker store but here it costs about 7 dollars a foot. but i should be perfectly fine running something like a 120 or 140 amp fuse then w/ that 2 guage id think. probably not as good of quality wire as some other brands since its just batt. wire but id say it could support that. i just didnt wanna cause an eletrical fire just tryin to feed my bass then be out a ride. i have heard from contractors that thats how most house fires start is when someone over loads the breaker and they just put a larger fuse in but the wire can support the draw and starts a fire. so if i put that amp breaker on it cause i have a extra 140 i belive it should work fine? it wont cause a fire w/ the alt would it sorry for all the questions in someone elses thread but im not to familar w/ electrical thanks
john

1meanGTA

those dudes are trying to hose you. order 1/0 from weldingsupply.com in any color, i believe its 1.75 a ft.

PhLaXuS

And I got mine for a little more, $2.55 I think, from:
http://www.hifisoundconnection.com/S...id/0/SFV/30046

$7/foot is way more than retail!

And here's a page with wire current ratings:
http://www.bcae1.com/wire.htm

1meanGTA

anything from 150-175 should be fine for 2 gauge. i wouldnt go any higher than 175, but you can go lower, can stick a 100 in there if you want, it'll just pop easier than a 150 would. i'd do 150 and call it a day.

justlearning

yeah i was pissed i saw that it was that expensive they used to carry some for about 4 dollars a foot and i didnt mind that cause it was cheaper and it was a flatter type of cable which was alot better for not leaving such a hump under the carpet but now they quit carring that and only carry rockford wire wich sucks but i was in a bind so thats what i got but i looked and will probably need a longer piece than what i got but im not positive yet i have to build my amp box first to see exactly where my cap is gonna be. yeah as long as ill be safe from electrical fire then i will throw that two guage on the alt. batt. and ground and and call it a day w/ the 140 amp breaker i have extra. would it be okay to run the alt straight to the batt. intsead of to that distributor spot on the side of the radiator (almost looks like a b+ terminal of sorts) then keep the small wire from the batt. to the terminal to feed those acc. id think it would be. cause i plan to leave the starter wire a stock size and just upgrade the pos. on alt. and both grounds cause i have no problem w/ starter volt. thanks
John

PhLaXuS

Yep -- just run the heavier wire directly from the post on the alt with the 8mm or 10mm nut. That's the alt output. Put the breaker in-line close to the battery. I'd suggest wrapping the wire with loom and securing it in place with zip ties or the like...

PhLaXuS

I turned the box around so the subs are now facing the hatch. It is rediculously louder than before (as I expected), but also muddier (also as expected). So I guess I'm gonna design a rather unorthodox ported enclosure for the rear well and see how that turns out. One question, though, is if I don't like this setup in the new ported enclosure, I will be swapping these subs out for something else -- probably a XXX12 or maybe XXX15.

I know SQ will be better all around, but does anyone know how the SPL will rate between one XXX12 or XXX15 and two 12L7's assuming 1500W to both setups?

1meanGTA

if you can make a ported box to fit in the well, you're my hero, and i'll pay you for the plans to build it.

i tried, and i dont think its possible using mdf unless you dont mind not being able to see out the back window. fiberglass it could be done, fairly easy i think, but fiberglass boxes aint cheap.

if you replace them, i'd go with 2 rl-p 15's sealed. i would have, but i didnt think i'd be able to fit a properly sized box for 15's in my car. the sound quality is as good or better than xxx's, and 2 12's will crush a single xxx 12. a single 15 would drown out an xxx 12, and 2 15's wouldnt even be funny against an xxx 12. also, you can push 2 rl-p 15's to their limits with 2000 rms. that kicker amp would be awesome for them, it'll drop to 1 ohm right? it would take that entire amp to run an xxx. they need about twice as much power as an rl-p to do their thing.

justlearning

there has to be something wrong here cause ive heard way to many of the subs be riduculasly loud and i have two im bout to put in my ride when i get the amp box built....how stiff do the subs still feel??

9177

Put them in the well area. also try giving them a little bit bigger box.

AudioDEO

OK free advise here.

1. the problem is your new subs now require alot more power than your old ones.

2. you have them facing forward they will never hit as hard that way.

3. you have them in a sealed box. The efficiancy is too low in sealed for the amp that you have you need the ported box to up your efficiancy.

suggestion 1. go to a shop and see if they will desighn a ported box for you to build.

suggestion 2. go to same shop and just have them build you one.

suggestion 3. Even though your in florida. I will build you the loudest best sounding box you or your freinds have ever heard and ship it to you. Ill give you free shipping too because you are a member of this board. I can test fit it in my firebird to make sure it fits properly.

hope this hlps. Keith.

justlearning

that amp he has is enough that those subs should bang but i didnt know taht the box wasnt in the well yet i thought u got one for the well for it...as for the size of the box if thats .88 after discounting sub displacement its enough but id give them a lil more. you could build a box w/ slot ports but the box will need to be much larger but ud have plenty of room if u took out the back seats and built it since thats where the box is now so i assume the seat isnt very funtional. depending on your carpentry skills you dont need anyone to build a slot ported box for you but if you want a perfectly tunned one or a bandpass box u probably will. but if you have those subs running at one or two ohm that amp and sub combo should be pretty impressive. i think its either a problem w/ equipment, wrong wiring, but really i think they still arent broke in you have to be patient w/ these subs as i said my friends took a very long time to get loose you should be able to gently press on them and be able to tell. then it could be the size of the box holding u back a lil bit but they should still sound decent assuming thats .88 after the sub displacement.
John

9177

I'm woth him. and this doesn't mean put a sorry 4" port in the box a real ported box. there simply is not enough room to have the right amount of port area AND have it tuned low enough to sound good.

AudioDEO

Ok the reality is this I cant make a ported box that will fit in the well sound good with two 12" subs but if it has to be in the well i can make 1 of those 12" hit so hard it will nearly run you out of the car!

Now if you could give me a little more room like say the well and all of the space above the gas tank to the back of the seat thats 6 cubes total i can make that sound really good. by the way you only have 3 cubes down in the well.

Now im sorry i cant make you plans because our box technollogy is proprietary. Butt i will give you free shipping and a performance gauratee If you dont like it ill give you your money back. Thats how confident we are in our enclosures. The only requirement from you is you have to have a freind take a picture of your face the first time you turn it on. LOL just kidding.

justlearning

that dosent sound too bad how much would u be talking about to make this box w/ the guarentee and what would it be tunned to?? cause i to just bought these subs and am just curious on what u would charge to make this thing cause right now i use that space above the tank to house my three amps (mtx 81000d, old orion gx series i belive 160 and an old orion gx 80 amps) and my 5 farad cap. but i could give up a back seat possibly for somethin like this? and im assuming this is made of 3/4 inch mdf?? i assume that would weigh a ton. but i was just curious on what kinda price u had in mind?
John

AudioDEO

sure ......

ok for

1 12" in the well $ 185.00

specs: Custom tuned to what ever kind of music you listen to and what ever kind of equipment your amp headunit ect.

slot or square port what ever happens to be optimal for your set up.

3/4 mdf, carpeted to match interior. custom drilled and sealed wire entrance. No pesky speaker box cups to wistle at you or leak air.


1 duel 12" in well and above gas tank $ 225.00

specs: same as above. both availabel in birch wood weighs about half as much. to give you an idea a sheet of mdf weighs abot 97 lbs where as a sheet of birch weighs about 66 lbs. I would have to check on the current price on birch but it usually adds about 30 to 40 dollars to the price.

design and construction would take about a day. We only need the type of music you listen to, the type and model of amp you have, whet brand and model of head unit you have, list of any other components that are in the audio chain to your subs, type of interior cloth or leather or viynel and of course what kind of sub you have.

We can also cover it in any material you might want for an extra price of course. viynel, carpet, paint, carbon fiber, you name it.

These prices are for thirdgen members only. anyone else is going to be charged more. i just feel like i need to give somthing back to you guys for all the help youve given me.

If you have anymore questions post here or call Keith at SOUNDWAVES 979-779-0065 mon - Sat 10:00 am till 9:00 pm or Sundays 12:00 pm till 6:00 pm. PS: Im off on Tuesdays so dont call then cause they will just trip on the price i gave yall.

justlearning

do u guys have a site to pay at or somethin?? how would that be worked out this would be a month or so but for that price id really am considering this depends on what i can get em to sound like non ported in the well

AudioDEO

You can pay be credit card by phone or send money order. just let me know.

1meanGTA

could you build a box for 2 12's that would accomodate these specs? (these are for each driver)


1.5 - 2.0 ft³
net vol. after driver and vent displacement
20 in² of Vent Area (minimum) (i'd want more like 30-35)
Vent Fb = 34Hz

AudioDEO

I certanly could ... However it may be better to run test and see if you woofer might not perform better in a little larger enclosure and yes you definatly want to up the port opening to the 30 -35 figure. will definatly cut down on port noise.

But if thats all the space you have i can make them sound the best possible in the amount of space.

if you can supply me with woofer model and brand , amp in use , head unit model number and brand, vehicle you want it in . and if i asked you this question. If you had to say i listen to this kind of music atleast 51% of the time it would be ______ . I can give you a price on it.

Thanks Keith.

AudioDEO

ohh PS.

speaker manufactures do enclosure test with programs that simulate whats called a half-space. Basically what would happen if you put a woofer in a medium sized room.

This can play havoc on a enclosures tunning since your vehicle is not the size of a medium sized room. Your car actually ends up being a box inside of a box... nOW if you dont take this into consideration. You will allways be way off on your tuneing.

Our proprietary program takes all these things into consideration before recomending an enclosure/port size.

This is why we can consistantly give you twice the output of conventional ported enclosures and still have the low bass output of sealed enclosures... "within reason of course we do generally curtail output below about 25 hurtZ or so depending on the customers needs. Now if you wanted a subsonic monster we can arange that aswell how ever your higher frequency will suffer in sound quality and uniformity.

THanks Keith.

1meanGTA

you're talking about a fiberglass enclosure then?

AudioDEO

no an mdf enclosure....

We could do an all firberglass or part fiberglass enclosure but it would considerably more expensive at the proper strength.

1meanGTA

have you ever built a ported box for a third gen?

9177

Id like to see it too. While I don't have any nifty software i know using simple math that a 3 cu ft box with 40" of port is a big box with a long port. There is room for the box but getting the port to snake around is next to impossible. Unless you go above the seats.

Jim85IROC

iTrader: (2)

There's plenty of room for a ported enclosure for a pair of 12s as long as you don't mind having the box extend all the way to the front seats. I built a ported enclosure for a pair of 12" Rockford HX2s and it pounded HARD. It was well over 140dB.

Oh yeah, I had 2 4" Aeroports in it too.

AudioDEO

Ive built tons of ported boxes for third gens we probably do 1 a month for third gens. "our cars arnt as popular any more... sniff, sniff,"
But ive been competing for more than 13 years Im currently working on a new box for 4 15's for my bird and yes its ported and no i dont have my back seat anymore. but who uses that thing anyway. Its just wasted space. any how you will do quit a bit more than a 140 on the dash with todays 12" and a good ported enclosure's

ohh well have a good one.