I bought two alpine type e 12 subs in a box with a 600 watt amp from my friend for 150. I put them in my car and they sounded good. Good enough for me anyways. But today when I was driving around they seemed really weak. My mirrors used to shake at full volume and now they don't. I haven't touched any of the setting on the amp or in my head unit. It was -12 degrees today if that matters.

Any help?

 

it might be the cold but not sure. the coils stiffin up when it gets cold and the sub will feel hard when its off if you try to push it in, my jl w3 used to do that last winter, my type x has not done it yet this winter. but i would also check the rca wires for the sub if you are useing a 2 channel to the sub maby one of the channel has a short, it happend to me when i bought some cheap *** rca, i stick with jl wirein and have no problems. check those things out and see what it does maby i can come up with somethin else if it not those.

 

Also, check the main fuse at the battery. I've seen the filament get warped causing a similar problem.

 

I'm confused. The amp is 4 channel- A, B, C, and D. Why did my friend wire it with the subs in parallel and the positive hooked up to +A terminal and the negative hooked up to the -B terminal?

Why not one speaker on channel a, and one on channel b?

Oh and i know this is a BIG no no, but there isn't a fuse on the power wire because by buddy didn't have one at the time (they've only been installed a week). I know its an easy fix, but I don't know what size to put in. Too small and I'll waste money replacing them, and too big and there's no point.

 

he hooked them up that way because when you hook 2 speakers in parallel it creates a low ohm load creating more power and quality (if one sub is 4 ohm and the other is 4 ohm, then if you hooked them up in parallel it makes them both 2 ohm but in series it would make it 8 ohm). you should always try to make you speakers operate at the lowest possible ohm your amp should handle. honesly if i hooked them up i would keep one of the subs over channel a+ and b- and then the other sub over c+ and d-. to do this if you are just running a 2 channel rca is to get 2, 1 into 2 y splitter rca cables so you have 4 rca ends to plug into the amp and 2 end into your h.u.

in my old car and in my monte ss i am not running a fuse off the battery and i have had been running some type of system in both cars, now with my biggest system i have 1200whatts total with 4 awg wire. I have no main power fuse off the battery and its been like this for 2 years and never had a problem.

to figure out what size you need add up the size of the fusses on your amp. ex. on the side of a Alpine PDX 1.1000 there is 4 fuses each marked with a 25 meaning that each fuse is 25 amps so for that amp alone i would need a main fuse off the battery would have to be 100 amps or greater. I have another alpine amp that has 2 25 amp fuses so off the battery i would need a 150 amp fuse.

its best to match it accordingly but its just fine to have one that is to big even 100 amps over would be ok. just make sure your fuse holder will accept whatever size wire you are using off the battery.

 

Because it's not a good idea to run subs in stereo, which is what you'd be doing if you ran them one on each channel. What he did is bridge the amp, combining two channels to one and increasing the power output of the amp.

Very big no-no there, fuse it ASAP. What guage wire is being used? Look at the jacket of the wire, it'll be printed on there. Fuse it according to wire size following this chart:

 

Thanks for the help guys.

I'm using 10 guage wire. And on the amp there are two 25 amp fuses.

 

cool. then you need a 50 amp fuse. i think most that low come in 60 but that be ok.

not sure if it work but if would do the y splitter thing i was talkin about you could try to take the subs and bridge it over all 4 channels a+ to d- keeping them in parallel to create a 2 ohm load using all 4 channels and use all of the amps power. it depends on the amps sometimes though. I have gotten a amp to work like that but some amps wont, maby worth a try?

 

Using the splitters like that halves the preout voltage, which means the amp will have to work harder and will be less efficient. And if the preouts are only 2v to begin with, lowering it even more has more cons than pros. I don't recommend that.

Knowing the purpose of the main power lead would clear up alot. The only reason you fuse that lead is to prevent the car from catching fire due to catastrophic short circuit (like if you got into an accident and the wire got pinched, or if somehow it got grounded out) via the stereo equipment. With no fuse there, in the event the wire got grounded out, you'd burn your car to the ground. Not a chance i'm willing to take, but to each his own.

Adding up the fuses on the amps is not the proper way to fuse the main lead, for a couple reasons.

1. Not all amps have fuses externally, like the well known Orion HCCA-D5000.
2. Not all amp manufactuers use the proper fusing on the sides of the amplifiers.

The right way to do it would be to fuse the lead according to it's guage since the only purpose for the fuse is to prevent the wire from catching fire in the event it gets shorted out. It's a misconception that the fuse will protect the amp or amps. If that were the case there'd be no need to put fuses on the amps themselves, right? And even those don't do much to protect the amps as I've seen many amps continually blow fuses and come to find out something inside it got fried, so much for the protection huh?

But if for some reason you really want to fuse according to the amplifiers, do it based on amperage draw of the amps. To find out what that is you have to know how much power each amp is wired to put out, start the car and check voltage at the amp, then divide the wattage of each amp by the voltage, the quotient will equal amperage. So if amp A is wired to put out 250 watts, and the voltage to the amp is 14v, the amperage will be 17.8amps. Add up the total amperage and get a fuse that size if you can, or you can go bigger by about 5-10%. But again, no need to do all that, just keep it simple and fuse according to wire size.

It's definitely not ok to fuse 100a over, unless you're running 1000 watts or more. However, and this is very important, if you're running 4ga power wire and you're fusing according to the improper method I quoted above, and let's say you have the same system specs as him so you need a 150a fuse, if you fuse it 100a over then you'll have a 250a fuse on a wire that can only safely carry about 150a of current (depending on the circular mils of the wire) before getting very hot and becoming a fire hazard.

 

Ya it makes sense. but i have the main power into a cap then into the dist block that has built in fuses for each output with correct amp rateings.

there is really more risk of something happening to the wire after the fuse at the battery then before the fuse at the battery. if the post is correctly covered and no metal can touch it even in an accident, then the fuse is pointless because its only usually about 6in of wire length its protecting anything after the fuse is unprotected and there is more obstacles there for the wire to get damaged if it is a cheap wire without proper installation and using a extra covering in higher risk areas. i on the other hand use expensive wire that provides the best current flow and protection. ex. if you have 20ft power wire and install a fuse 6in away from the battery then the fuse protects 6in of wire, between the batt and the fuse, the remaing 19.5ft is unprotected if the fuse is connected. this 19.5 ft has more chance to fail the the first 6in.

thats why i never installed an inline fuse at the batt. even though i do have one in the car that i never have installed yet that is rated at 175amp that will be protecting a 1000whatt amp and a 300whatt amp with 4awg wire. so tell me what the fuse amp should be useing your calculations compared to mine 04monteLs

you could split the rca wire yourself too and loose no connection