electrical question weak sub

[msgtcody]

So I have sort of a rare crap car that I thought I would try to make as cool as possible but its not so cool so far. I have a 1993 Subaru Justy which I just found out has a 55 amp alternator.

I have an RE Audio SXX 10 that is 1000 watt rms

I have a Rockford Fosgate R 1000 amp that is 1000 watt rms at 2 ohm which is what I am running.

Everything is run with 4 gauge wire and the big 3 upgrade has been done to 0 gauge.

Heres the thing, I don't have any light dimming problems or issues with the amp cutting off or cutting out, its just not loud. I get a max 105 dbs out of the thing wide open. Also the subwoofer basically does nothing without the Gain on the amp maxed out. I previously had a Hifonics Hfi 1000 wired at 2 ohms which was getting about 500-600 watts and it was louder than this is.

So my question to you is what is the problem here and what are some things I should try to do? Is it because this amp is more powerful that the alternator issue is now a problem? Is the amp bad? (its brand new today) Why does the sub only begin to get loud with the gain maxed out?

.....and where the do I find a more powerful alternator for a 1993 subaru justy?

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[skylineTT 10+ year member]

you should get a bigger alt anyway, but as far as your amp not putting out power, check the RCA (signal) connections at the amp and head unit. also, check the head unit itself. Is it aftermarked or factory? If aftermarket, what is it? If aftermarket, check the subwoofer settings on the unit and check to see what channel the RCAs are plugged into on the head unit. on a lot of units, there is a subwoofer specific channel, on some other units, there is only one channel that you can use but the subwoofer setting has to be turned on.

 

[msgtcody]

I have a Sony CDX GT550 UI. RCA cables are plugged in to the rear sub out and everything seems to be fine. Like i said i came from a 600 watt amp and upgraded to this 1000 watt rms rockford fosgate. it basically does nothing without the gain at 8 or above. i took it out and put it in a camaro with a 130 amp alternator and basically the same thing, no power below a gain of 8. my thoughts were surely something with a birthsheet and cea compliant rated over 1000 watt rms would be louder than something 600 watts and not cea compliant. its very loud with the gain maxed out but surely thats not required to get this thing to run effectively?

 

[sacsking916 5,000+ posts]

are you positive you didnt somehow someway wire it wrong? thats another possibility as well.

 

[Robert 2001 10+ year member]

Sounds like your not getting a good signal to the amp. What load are u putting on the amp?

 

[bubbagumper6 5,000+ posts]

What's the wiring configuration of the sub?

 

[kramer_212 10+ year member]

if your alt is only 55 amps, i know that that amp is super efficent but it pulls m0re than 55 amps full tilt, you should have headlight dimming, check your amp ground.

 

[RangerDangerV2 5,000+ posts]

could be a poor enclosure.... and dont MAX the gain out because you are clipping the hell out of your sub.

 

[VisceralSound 10+ year member]

if your alt is only 55 amps, i know that that amp is super efficent but it pulls m0re than 55 amps full tilt, you should have headlight dimming, check your amp ground.

This^ I'm running 1k watts on my Alpine MRX-M100 and depending on the song/little fiddling with my gain I just barely get light dimming (105a Alt) It used to be pretty bad until I swapped the ground to the opposite end of where I had it, forgot to put it on the unpainted side.

 

[akheathen Premium Member]

um, what are the amp settings at? do you have a knob plugged in? it could be that you do need to have the gains up. play a tone from the head unit and measure the vac voltage from the rca pin to shield and see what voltage you are feeding it

 

[akheathen Premium Member]

oh, and look to match up the alt with other scubaru and nissan for models to go off of.

 

[msgtcody]

Alright guys thanks for your ideas and suggestions just wanted to let you know where I'm at right now.

I moved the amp to my other car with a 130amp alternator like i said above and it still does absolutely nothing without the gain way up. As others have said doing that causes the sub to clip badly and sound terrible. It seems like this amp is either all or nothing. I've hooked the hifonics to the sub which is only putting out about 500 watts and the difference is night and day. 2 different cars, 2 different amps, grounds, wiring setups and the only failure is when the rockford amp is being used. I don't have any way to test the power coming out of it but it can't be putting out more than 100 watts at anything under max gain. By comparison I can set the Hifonics down to 0 and it still be more powerful. Surely this has to just be a bad amp?

 

[skylineTT 10+ year member]

It might be.. They are tested but idk. Can you send us a pic of how you have the sub wired exactly? Not to insult your intelligence at all, but sometimes they are wired incorrectly and the amp could be seeing the wrong load.. Idk how rockford amps act below output impedance rating but it wont hurt to check..

 

[disturbed471985 5,000+ posts]

Alright guys thanks for your ideas and suggestions just wanted to let you know where I'm at right now.
I moved the amp to my other car with a 130amp alternator like i said above and it still does absolutely nothing without the gain way up. As others have said doing that causes the sub to clip badly and sound terrible. It seems like this amp is either all or nothing. I've hooked the hifonics to the sub which is only putting out about 500 watts and the difference is night and day. 2 different cars, 2 different amps, grounds, wiring setups and the only failure is when the rockford amp is being used. I don't have any way to test the power coming out of it but it can't be putting out more than 100 watts at anything under max gain. By comparison I can set the Hifonics down to 0 and it still be more powerful. Surely this has to just be a bad amp?

Go to lowes/depot buy a dmm (can get for under 20) pop in a test tone and check the ac voltage coming off the amps speaker terminals. This will tell you what kinda power the amp is producing..

 

[VisceralSound 10+ year member]

Could also goto your local audio shop and they can bench test it for free and troubleshoot you any issues.