loud interference on new speakers

can someone PLEASE help me pin-point the source of this problem.

i install a panasonic strada hu and hooked it up to an amp for the subwoofer and everything was awesome... but then i installed a 4 channel amp for the four infinity speakers that i installed. now there is a "hiss" when the radio is on and in get louder when the truck get turned on. the "hiss" does not get louder with the volume up but if i turn the volume down, i can hear the rpms on the speakers.

so far i checked for any contact with metal-speaker and there is none. also i inslated the rca cables behind the hu, and all grounds are nice and tight.

can someone please help me? thanks

 

did you run your ground wire and you power wire on the same side? if you did thats your problem

 

you need a ground loop isolator. its a little box that plugs in between your amp and RCA's and it cuts out that whining sound. I had the same problem on my last truck.

 

what do you mean? what i did was get one of those blocks where the main wire coming from the battery connects to it and then two power wires come out of it one for each amp. the ground wires are connected separately on two different places. one amp is under the pass seat and the other under the driver seat. thanks.

 

where do i get this ground loop isolator, do i just ask for one?

i will google it to see how it looks...thanks.

 

also, would i need one for each...so i guess i would need 3 of them. how much are they???? would they connect on the hu side or the amp side?

 

we used to call this alternator whine.

it comes from improper grounding.

 

the ground wire from the amps are connected to the bolts of the seats...i checked the grounds on the speakers and they are all good. the ground from the speakers to the amp is also good. am i missing something???? thanks

 

Did you strip any of the paint off to make sure you were making a contact to bare metal?

 

Doesn't the fact that he actually "hears" the whine mean that the amps have power, meaning the ground is good? I always thought alternator whine came from running the power from the battery along side the speaker wire or RCA source cables...

 

yep...

 

if your ground wire and your wire coming from the back of your radio are to close together it will wine....a guy brought his car into the shop last week and that was his problem....

 

Not likely the issue.

Not quite right, IMO.

Yep, that is what we call it too.

Good point

Yes, they have power, no the ground isn't good. It rarely if ever comes from running wires next to each other. Common misconception or rather misdiagnosis of the issue.

I have never seen this be an issue. I am not trying to call you out or say that you are wrong. I am saying no because that is rarely if ever the issue. Alternator whine is typically due to an improper or inadequate ground connection. Sometimes the area that you are making the ground connection to can be corroded, loose (most common), or the paint and primer coat are still there. It is almost always (in my experience) due to one or more of these issues. I have never seen (heard) RCAs running parallel, near, across, wrapped up together,or any combination induce audible noise into the signal.

You most likely do not need a ground loop isolator if you correct the ground connection issues. Also, keep the ground wire as big or larger in diameter as the power wire, make it a common point for all amplifiers and keep the run as short as possible (< 18" is ideal). Ideally it should connect to the frame in a solid manner, or be a very solid point of connection to the body (seat belt bolt is ideal for this). Occasionally, if there is an issue with too much power going to a point on the body, but this is exceedingly rare. So, most likely not your issue.

 

Yea, save the ground loop isolator for last resort. check all your grounds and if you still come up with the whining then I would go ahead and run one. When I had to run one I bought it at wal mart for like 12 dollars

 

Just to be clear, is it a "hiss" like the sound of a snake or a "whine" kinda like the sound of a supercharger? If it is a hiss as you initially mentioned and does not increase with volume I doubt it's a ground issue issue and most likely it is an issue with your gain structure or something in the amp. How did you set the gains?

 

I use the gains as a volume control... am I doing it right Marv?

 

Also did a bit of reading, here's some other things to check:

• Some people are saying that the seat connection bolts are not a good choice (I'd say it's how you prep your surface). I like sooner's idea of the seatbelt since the belt portion and bolt are already bare, so just need to strip off the paint on the truck where it connects.
• Check your RCAs for proper connection. Seat them fully on the connections
• Try removing the RCAs from the head unit and turn the vehicle on. Still have a hiss? It could be a bad amp
• Apparently Pioneers have problems with grounding (might be an old issue, my pioneer was/is working great, but worth noting). Here's a fix for this and some other troubleshooting tips: http://bcae1.com/images/rca/temporaryrcashieldrepair.html

 

If you are hearing the rpm's of the engine then it is a ground issue and you have a "ground loop". A ground loop is when your ground is less than perfect and it the amp "looks" for another source for ground and typically it is the RCA's and hence you get noise. Check over your grounds and move them around, back in the old school days this noise was very very common and sometimes tough to get rid of but with the newer gear it is much easier.

 

I must have misread the part about the RPM's which now would lead me to believe it's actually a "whine".

 

so i should get a bigger size diameter wire for the ground and maybe connect it to the seat belt bolt, right? i will def. try that...btw bought the ground loop isolator just because i had a three hour trip and i did not want to hear that effing noise...anyways, it helped a little...it is one of those that have a black box with two input and two rca cables coming out, and two brown wires as well, my question is where do i connect those two brown wires...are they just grounds?