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Thread: No bass sound after installing ground loop isolator |
    
New member Username: Troy_barker
Post Number: 1
Registered: Jan-06
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| Posted on Monday, January 23, 2006 - 05:52 pm: |
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Hi
I am in need of a little help on my new car audio system.
Every thing is grounded with soldiered ends. As well as powered the same way.
Amp is in the trunk, head unit is under the front seat.
Speaker cables are run down one side of the car and RCA and remote switch is run down the other side.
Head Unit : Pioneer DEH P3700MP .............50 Watts x 4 channels
Amplifier : Phoenix Digital 1200W 2ch 175W X 2 ch @ 2 ohms or 125W x 2ch @ 4ohms or 350 x 1 ch
Subwofer : 1200 Watt Sony Xplod
2 6x9 Pioneer mounted in the package tray 200 W each.
I have installed a 10 Amp Noise Filter and a Ground-loop isolator
Reason for installing the noise filter and ground loop isolator is because I had one loud engine noise and a chattering sound. It has appeared to take care of the noise.
Speakers are connected to the AMP on the left/right + /- terminals. Sub is bridged across the L + and R - terminals.
Problem is that the amplifier does not appear to be outputting any bass. However when I remove one of my RCA cables that run from the head unit to the amp and touch it on the face plate on back where it was connected I start hearing bass. However when I plug it back into the AMP no bass. It sounds like the treble is really high.
Any suggestions would be greatly appreciated.
Troy |
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Gold Member Username: Tjmutlow
Post Number: 1167
Registered: Sep-05
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| Posted on Monday, January 23, 2006 - 06:16 pm: |
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is that a dual voice coil sub or a single, i do not think you can run that amp like that, but you could have a bad rca or a bad input, and how is the setting set on amp, low, full or high, you need lowpass for sub , but then the speakers wont work right. |
New member Username: Troy_barker
Post Number: 2
Registered: Jan-06
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| Posted on Monday, January 23, 2006 - 06:33 pm: |
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Let me explain a little more in depth. Then I will answer your questions.
When I first installed this it worked ok for about 2 days.
I then picked up a real loud engine noise. I then added the noise filter and that did not seem to help. Once I installed the Ground Loop Isolator all of the noise went away.
It is at that time I started to notice I had no BASS.
I have my Sons AMP and Sub hooked up like this and it works fine. Just like mine when I installed it for the 2 days it worked.
To answer your questions:
It is a single voice coil.
AMP is set on full.
I have since unhooked my Sub and still the problem remains.
How do I know how big of noise filter do I need 10/20 AMP?
So is what you are saying is I either hook up my speakers or the AMP but not both?
Troy |
Gold Member Username: Southernrebel
Monroe,
Louisiana
USA
Post Number: 1878
Registered: Mar-04
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| Posted on Monday, January 23, 2006 - 06:38 pm: |
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try it without the noise filter...just use the ground loop isolator.
also...what RCAs do you have? |
New member Username: Troy_barker
Post Number: 3
Registered: Jan-06
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| Posted on Monday, January 23, 2006 - 06:45 pm: |
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I pulled the GLI out and the BASS comes back. Of course the engine sound comes back too. 
Can a GLI be bad?
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Gold Member Username: Southernrebel
Monroe,
Louisiana
USA
Post Number: 1881
Registered: Mar-04
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| Posted on Monday, January 23, 2006 - 06:49 pm: |
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maybe...
you could always take the GLI back to where you got it and exchange it. |
Silver Member Username: B101
Queen City,
NC
USA
Post Number: 661
Registered: Sep-05
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| Posted on Monday, January 23, 2006 - 07:15 pm: |
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what is your amp grounded too?
sound like a floating grd. |
New member Username: Troy_barker
Post Number: 4
Registered: Jan-06
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| Posted on Monday, January 23, 2006 - 07:15 pm: |
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OK, just got back (exchanged the GLI)and hooked it up and still the same thing. No noise and no BASS?
Not sure what would cause this behavior. |
New member Username: Troy_barker
Post Number: 5
Registered: Jan-06
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| Posted on Monday, January 23, 2006 - 07:18 pm: |
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Ground is the trunk lock bracet on a 67 Nova, head unit is grounded below the front seat to the seat track bracket.
As for the RCA cables, I beleive them to be good since it works without the GLI.
Thanks |
Silver Member Username: B101
Queen City,
NC
USA
Post Number: 663
Registered: Sep-05
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| Posted on Monday, January 23, 2006 - 07:27 pm: |
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let me get this straight.
so when the GLI is hooked up, is the amp even powering up??
Seems to be a bad ground!
First start by grounding the amp somewhere else.
Then we can check your wiring of the GLI.
When you replaced GLI did u use another brand? |
New member Username: Troy_barker
Post Number: 6
Registered: Jan-06
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| Posted on Monday, January 23, 2006 - 07:34 pm: |
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Yes you are correct with the GLI connected the AMP does power up and I can not hear the bass.
I did replace GLI unit with the same brand.
The wiring of the GLI it straight forward 2 in 2 out. No marking as to what end is in but I did flip them and behaivor is the same.
I will go and ground the amp elsewhere........
Thanks |
New member Username: Troy_barker
Post Number: 7
Registered: Jan-06
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| Posted on Monday, January 23, 2006 - 08:21 pm: |
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Grounded AMP to body chassis in the trunk then to the frame.
The following is with the car NOT running.
I removed the GLI and the BASS works, however when I turn the speakers all of the way down I hear thump thump thump like a cycle of some sort.
So that was getting worst, I moved it back.
??????????
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Gold Member Username: Tjmutlow
Post Number: 1172
Registered: Sep-05
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| Posted on Monday, January 23, 2006 - 08:46 pm: |
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what gli, and try reversing the way it is hooked up, some glis, have to be hooked up directional. |
New member Username: Troy_barker
Post Number: 9
Registered: Jan-06
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| Posted on Monday, January 23, 2006 - 08:50 pm: |
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GLI is a radio shack
I did flip the GLI in the other direction. |
New member Username: Troy_barker
Post Number: 10
Registered: Jan-06
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| Posted on Monday, January 23, 2006 - 10:59 pm: |
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any other suggetions? |
Gold Member Username: Mikechec9
Http://www.cardomain.c...
Post Number: 2043
Registered: May-05
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| Posted on Monday, January 23, 2006 - 11:41 pm: |
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lose the gli and manually isolate the noise.
http://electronixwarehouse.com/education/accessories/aboutnoise.htm
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Gold Member Username: Mikechec9
Http://www.cardomain.c...
Post Number: 2044
Registered: May-05
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| Posted on Monday, January 23, 2006 - 11:45 pm: |
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http://www.carsound.com/cgi-bin/UBB_CGI/ultimatebb.cgi
richard clark's "on audio" forum also has helpful threads if you search the subject. |
Silver Member Username: B101
Queen City,
NC
USA
Post Number: 675
Registered: Sep-05
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| Posted on Tuesday, January 24, 2006 - 05:04 am: |
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they way u wired that amp, seems a bit strange to me. your highs still play off that same amp when the bass stops? |
Bronze Member Username: Troy_barker
Post Number: 11
Registered: Jan-06
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| Posted on Tuesday, January 24, 2006 - 02:24 pm: |
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Ok, I wired the AMP different, I removed the sub and only have the 2 6x9 connected.
I already read the info suggested above.
I move the HU to the trunk where the AMP and the battery are located.
I grounded the AMP and HU to the same place. I connected the AMP and HU to the battery.
Still I have noise......I removed the noise filter and it made no difference.
I connect only the RCA (short ones) between the AMP and HU. Connect power and ground.
With this only I hear the noise. I then connected the GLI and again the noise went away but the Bass also went away.
Yes the highs still play on the AMP when the bass stops...........
I am still trying to determine what is causing this strange behavior.
Troy |
Gold Member Username: Carguy
Post Number: 5237
Registered: Nov-04
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| Posted on Tuesday, January 24, 2006 - 04:49 pm: |
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Where is your battery located? Under the hood or in the truck at the back?
Why is your HU in the trunk/under the seat? What about your dashboard?
Are the 6x9" speakers powered from HU or by the amp?
When do you exactly get engine/alternator noise?
If you only use the HU to power the speakers, do you still get noise?
Does the HU have front/rear/sub RCA connectors?
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Bronze Member Username: Troy_barker
Post Number: 12
Registered: Jan-06
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| Posted on Tuesday, January 24, 2006 - 05:23 pm: |
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The battery is in the trunk.
HU currently in trunk to help isolate the noise issue. Reason it is mounted under the seat normaly is because I do not want to cut into the dash....67 Nova.
6X9 are powered by AMP only.
I only get the noise when the car is running.
The head unit only has front and rear RCA jacks.
I will go check on the speaker wired directly to the HU. |
Bronze Member Username: Troy_barker
Post Number: 13
Registered: Jan-06
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| Posted on Tuesday, January 24, 2006 - 06:02 pm: |
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NO noise with the speakers just connected to the HU. This is with the car running.
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Gold Member Username: Carguy
Post Number: 5238
Registered: Nov-04
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| Posted on Tuesday, January 24, 2006 - 07:43 pm: |
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Okay, now connect the front's rca to the amp and test it.
Sometimes, the HU has as problem with front and rear rca plugs.
Don't worry about front and rear signals (they're both the same). |
Bronze Member Username: Troy_barker
Post Number: 15
Registered: Jan-06
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| Posted on Tuesday, January 24, 2006 - 08:09 pm: |
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did you want me to reconnect the speakers to the amp?
I tried both rca jack the same from both. |
Bronze Member Username: Troy_barker
Post Number: 16
Registered: Jan-06
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| Posted on Tuesday, January 24, 2006 - 08:12 pm: |
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I did leave the front speakers connected to the HU. If I do this and only connect the sub to the bridged output I can barly hear the noise, that is with LPF applied.
Should the LPF be engauged if I only leave the sub connected? |
Gold Member Username: Carguy
Post Number: 5241
Registered: Nov-04
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| Posted on Tuesday, January 24, 2006 - 09:07 pm: |
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For now, why don't you try using the HU to power the speakers and the amp to power the sub?
Leave the LPF on for sub. |
Bronze Member Username: Troy_barker
Post Number: 18
Registered: Jan-06
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| Posted on Tuesday, January 24, 2006 - 11:33 pm: |
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Thank you very much.
Troy |
Silver Member Username: Symplestiles
Stockton,
CA
Usa
Post Number: 456
Registered: Aug-04
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| Posted on Wednesday, January 25, 2006 - 02:55 am: |
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hey troy, which side of the car do you have your actual power wire for the amp on? make sure its on the oposite side of where the RCAs are.. i re-read your original post a couple times and never see you mention the amps power wire (the one connected to your battery) |
Bronze Member Username: Troy_barker
Post Number: 19
Registered: Jan-06
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| Posted on Wednesday, January 25, 2006 - 07:57 pm: |
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The battery is in the trunk and the amp is connected directly to it, about a 4' power lead.
RCA cable are nowhere near the power cable.
Thanks |
Silver Member Username: B101
Queen City,
NC
USA
Post Number: 717
Registered: Sep-05
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| Posted on Wednesday, January 25, 2006 - 08:50 pm: |
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u have 1 batt correct?
check your big 3 wires!
this could be the damn noise your getting..
I would redo the ground to engine, and ground 2 chasis. Also check pwr from alt to battery.
how is your batt chargin in the back? I would run a new wire for that also. |
