Grrr. . .

[Krazny]

Alright guys,
After getting everything hooked up and wired, I cant get my system to run right.
The Head unit is good, and all the wires seem to be right, but when I turn on the Amp and the subs, it sounds like someone is scritching their fingernails across a blackboard in short (less than one second) bursts.

Any ideas on how I can fix this?

The only thing I can think of is that it isnt grounded right. But the bolt I have it hooked to goes thru to the body. I think.
Its an Alpine head unit hooked to a Legacy Amp with MTX subs.

[blazen]

i know my friend had to ground his to the frame because he was gettin noises but i got mine through the body and it works fine. actually mine is grounded through one of the bolts that hold the seat down. i have legacy amps too. are all the setting on your amps right if it just going to subs make sure you got the low pass filter on. with out actually knowing exactally how to fix it i would say try changing your wireing around alittle you said subs so i'm guessing you have 2 try just hooking it up to 1 and see if that does anything for ya. just re check all your wireing make sure they all hooked up right. and i dont know if your head unit has a seperate set of rcas just for subs but i know on mine you can turn them off through the settings on the radio. look through your alpine's manual to make sure you got the setting right.

[bvr775]

sounds like a bad voice coil or you reversed the polarity of the subs (check wiring + to + / - to - )

[blazen]

usually reversed polarity will still play just not as good

[bvr775]

with some dual VCs that have to be wired together if you cross them up it'll sound blown.


If both subs are doing it it's in the amp you may have them wired wrong and your amp is cliping.
It really sounds like a blown VC though. Ok so you bought them new? what you've never pulled something out of the box that was broken. somtime it's just a manufacthring flaw(you actually thinck they check every speaker off the line) or they may have gotten drop in shiping. check everything and if it's still doing it return the subs. When you've done as many installs as I have you find out that about 1/3 of the subs you install are bad out of the box.

[blazen]

i would try the subs hooked up to another power source or try different subs to your amp either way that would give you an answer if it was the subs or not.

really 1/3 are bad out of the box that sounds like alot. i do belive it though. quanity not quality thats there problem.

[Krazny]

The components were my bro's, he pulled them out after upgrading. They did work when he pulled them out and put them in storage.

I'll check the polarity of the wires to see if its that. Not sure how to 'tune' the head unit, it appears to be plug an play.
The RCA cables are run and hooked up right, unless one got unplugged from the head unit during install. I'll double check tomm, and see.


VC?
Low Pass Filter?

How do I check/adjust these?
(I am a stereo n00b. . . .)

[blazen]

you cant adjust the vc's (voice coils) there just there they pretty much work or they dont. if you have dual voice coils you will have 4 places to hook up the wires on each sub.
the low pass filter there should be a switch on the amp it self. it might say
hp full lp
(high pass filter) ( full range) (low pass filter)

there might even be a knob that you can use to adjust these. usually want the knob around 80-120 for subs (with the low pass filter on) thats a pretty good area but you can adjust it to what ever you think sounds better that just a good starting point.

the low pass filter just takes out the high frequencies so only bass is played (good for subs). the high pass does the opposite. and full plays everything.

some head units will have these built in to them so that the signal comeing out of the rcas will only play what ever filter is on. so this could be a problem if the head unit is on high pass and the amp is on low pass than nothing will play. thats why i said check the settings in the head unit.

[bvr775]

I have the most problem with kickers. every outher sytem i deal with that has kicker has some sort of problem with the subs directly out of the box. MTX, audiopipe, audiobahn, pioneers and sony comming in second. Usely casesed by bad winding in VCs. with kicker solos a bent frame that cased a ripped cone. And my personale favorate sub shops that put used componets back on the shelf after a return because they "TESTED THEM" and there was no problem.

[T Man]

Check your ground. I used a cab bolt. It is either that or something is wrong with your RCA cables.

[XxInFaxX]

i think the amp is cliping. if its in < 1 second bursts it sounds like it is powering up, cliping off because of god knows what, and repeating the cycling. might want to make sure all the power wiring is correct. check for any shorts. make sure the +, - and remote on the amp side are clean connections. One frayed wire end could touch another terminal and its bad. really sounds like a wiring problem to me, not so much the input of the amp, but the output. so check all the powering of the amp, and check the outputs that are going to your subs. make sure you have the wires from the amp to the subs perfect!

[bvr775]

if the ohm load is wrong for the amp it will cause it to clip as well.
It's harder to explain this than it is to show someone, unfortunaly I can't show you in type. let me send you to good site that probally has some tech articles explaining all this.
http://www.the12volt.com/

[joker2040]

Check your ground for sure. That is one of the most common reasons for random noise that I can think of. If you look in the articles section I have a nice one in there about wiring and such.

[blazen]

as you can see with all the replys theres tons of things it could be, you just gotta start with something and go from there. it could just be a trial and era kinda thing

[Krazny]

Well, I should be able to mess with it on Wed, as I have projects, papers and exams tomm.
I'll try the ground first, then the filter thing, and then I'll check the connections.

[blazen]

good luck wireing is just a pain in the a$$

[Krazny]

Well, I really went over it this afternoon. Still don't work.
I can't figure out the Low Pass Filter, as it isn't on the amp. Only thing I can see is the Volume.
The ground isn't good enough, tut as I lack enough wire to do it right, I'll have to wait till next weekend to buy the parts needed. For today, I used a steel rod and stuck one end in the ground, and attached the wire to it. Other than that, I checked the wiring, and its correct. Only problem might be that there is a break in one that I can't see. I highly doubt thats it however.
I was able to get the amp powered up and the subs to stop chirping, but no sound to come out, and I set up the head unit for subs as per the instruction book, but was unable to get the subs to play. Which leads me to believe that the amp is toast.

So, Anywhere I can send it off to be checked out and repaired?
Its a Legacy 240W amp

[blazen]

you know i ended up screwing up my legacy amp. i accidently touched the power wire to the case when the the ground wire was also hooked up. it sparked but than the amp wouldnt work any more. so itook the cover off and i had fried one of the wires inside so i just solidered it up and now it works fine. so maybe you did something like that

[xtc_customs]

sounds like a possible ground problem . in a DC system power flows from pos to neg . so the grnd wire is just as important as the power wire . and should be treated as such .

cheap wiring could also be the problem as poor sheilding can lead to noise tranferance .

running through this myself the 1st thing i would do is properly ground the system with the same guage wire as the power cable . preferably to the frame . it has to be grounded to bare metal so scrap away grime and paint that is there . if that is not an option scrape away all the paint from a chosen area in the interior bodywork and use a self tapping screw to secure the ground .

check the system to see if it works .

is the amp on ? if yes check the speaker connections . if all connections are good check the RCA path to make sure it is connected . if all looks fine get a digital multi meter (DMM) . read directions . set to OHM (impedence) put red lead on the pos terminal of the box and the black lead on the neg terminal of the box . and let us know what it reads , the model # of your subs and weither dual VC or single .

if the amp has no power check the fuses . replace fuses if needed . sometimes a fuse can be blown and you will not be able to visually see it . if still no power check the remote wire .

run through this and let us know what you come up with .


though if you have a shop nearby they will most likely do a diagnostic and possibly fix your system for free providing you pay for any parts and materials . most shops do this as a free sevice to help promote business .