Constant Static noise when power on
 

I have read and read and searched and searched and I can't seem to find an answer to my specific problem. I have constant static noise when power is given to the speakers. It seems to be worst from the rear speakers especially my rear righthand speaker.

Speakers are:

Infinity Kappa 60.7cs front
Infinity Kappa 62.7I rear (major static)

Amp:

Infinity Ref7541a

Head:

Pioneer DEH-P310-UB

Amp power 4 awg gnd 4 awg speaker wire is all 14 awg and using two sets of 97% sheilded RCA's. Also I did a ghetto sheilding (aluminium foil taped) at all the intersections of speakerwire and the RCA's. Speaker wire is passed on seperate side of the car from RCA's, car is a 1993 Mazda Rx-7 FWIW.

Specifically all four of my speakers exhibit static noise but the rear right makes it annoying to the point where I couldn't go for a drive. Yesterday while doing a test I had only the rear right plugged in and it acted funny (tested for literally 10 seconds intermitent maybe 2 times 5s) I am wondering if that could be related in any way.

Any help or ideas would be appreciated.

Sounds like a bad amplifier. Find a different amp and try it. Disconnect all speakers and hook them up one at a time as well.

Well I don't exactly have an amplifier on hand to try out another. Is there any tests I can do on the amplifier itself?

Get an MP3 player and a RCA to 3.5mm (headphone jack) cable. plug RCA's into the amp; 3.5mm to mp3 player. This will tell you where you can start to look for your problem. Amp, or deck.

Disconnect you RCA's at your amp and use an MP3 player or discman with an 1/8" to RCA adaptor and connect to this your amp instead of your head unit. If the sound is still dirty you know it isn't being picked up from your RCA's or HU and is the amp, amp power/ground or speaker problem. But if is clean you can rule out those issues.

You can also rule out your RCA's picking up noise by using this same MP3 player method at the RCA connections at the head unit. Disconnect the RCA's and using another adaptor hook the MP3 player there, this will tell you if the noise is coming from the RCA's or originating at the HU it's self.

Next you can do as Rob said and disconnect all speakers and reconnect one at a time and check the results, it could be a shorted speaker lead feeding back through the system some how.

Also ensure all your power and ground connections are good to your amp and HU.

This should yield some answers for you.

BTW, routing your RCA's away from power sources is more an issue than speaker cables, especially amplifier power or other sources that may draw alot of current. If you have to cross paths with a power cable it is best to cross at a 90 degree angle to it. This minimizes the area of electromagnetic flux that the RCA is exposed to.

Hope this helps.

Lyle

Forgot to mention thank you for the fast reply. Just did a quick test disconnecting individual RCA's from the amp and even when an RCA is disconnected the static is still present in the concerned speaker does this mean anything?

Also I have the amplifier taken apart now so if there is anything I can look for there, I checked to see if any resistors were burned out or if any connections were desoldered and I can't see anything.

To add on to all the great things one front right speaker is now doing this constant thumping ala maximum excursion but no sound comes out any particular reason for that? Whenever it is connected it starts doing it and the Clip light flashes on my amp, is Infinity junk in AMPS?

*While typing this two responses man you guys are fast!!! You sure this is an audio forum and not a performance forum?

Also, Kyle would it be best that if they are to cross (power and RCA) that they be sheilded from eachother somehow?

Double check the ground and DISCONNECT ALL THE SPEAKERS like first mentioned. One speaker dead shorting is enough to send the whole works into protection or make the amp do odd things.

Try disconnecting the speakers like mention previously also try them on different amp channels aswell and make sure your power and ground connections are all perfect.

It is possible a single stray strand of wire could be shorted to ground or and adjacent terminal. This could cause this affect, I've seen it before. Also, if you have a small bookshelf speaker from your house or something similar that you can use to test with that will help you rule out bad speaker wiring too.

Definately related to your amp, though. I don't know much about infinity, but I would expect them to be pretty good. Not like Boss Audio or similar garbage.

Lyle

Thanks for all the pointers I will go out and buy an RCA to 3.5mm adapter in the AM and try all the steps suggested before haggeling you guys with questions.

Ohh and while removing an RCA from my amp the receptable came out stuck onto the RCA....

When you say disconnect the speakers one at a time do you mean just disconnect them from the screw in terminals or do you mean disconnect the associated RCA and the leads going into the screw in terminals as well.

FWIW about the ground the headunit is grounded reusing the OEM ground.

And out of gratuity:
http://i33.photobucket.com/albums/d52/theright7/Rx-7/Rx-7FirstDay2009002.jpg

Disconnect all the rca cables and speaker wires from the amp. Hook all the rca cables into the amp, turn the power on. Then start hooking speakers up one wire at a time and post the results.

I'm not convinced there is much you can do to shield your RCA's if they have to cross power. Wrapping stuff in foil could do as much harm as good.

I would say, just route the RCA's as far away from other wires as possible, making high current cables first priority, then low current, then speakers. If you are forced to run cables near wires you can also find what they are for. If it is a wire carrying an intermittent source, like a small overhead light that is only turned on when the door is open or a power trunk release. Voltage may be present, but if there is no load on the wire it is going to put out little to no interferance. Use this to help decide the lesser of the wire running evils.

On that note, anything you can do to limit the amount of current flowing through those wires the better. For example, using LED tail light bulbs instead of incandescent. These use far less current and would make the wires that power them emit less interferance. Please keep in mind that is just a point, don't run out and spend $200 on LED tails thinking it will solve you noise woes. If that is you sole purpose than that $200 could be better spent.

BTW, nice ride! That sucks about the RCA, I hope you can fix it and it won't cause you problems with your troubleshooting. Some of the cable brands make there RCA's so tight, I've heard of this a few times before. Mostly with Monster Cable home audio stuff though. It's rediculas... nothing needs to be that tight. Well maybe some things... ;)

Lyle

Alright little status update.

Did the test of removing speaker wires and it felt as though regardless of which channels were used or how high the input sensitivity on those channels is there is still a static present.

Did the tests with the RCA's to find that static is still present but discovered something frustrating. The Rear channels only allow low frequencies from the HU but when I plug in the Ipod touch boom the rear channels pass all frequencies. Does this mean my head unit is bunk?

Also how does the HU test go? I got two sets of pre-outs.

Well I did some reading of your manual and it seams that your HU's two pairs of RCA's are switchable. The rear can also be used as a subwoofer preout as well. So I'm pretty sure what has happened is that rear preout is set to subwoofer mode, and as such has its low pass crossover engaged.

So, what you'll need to do is change that setting to front and rear only and that should fix that problem. I have attached a the address to the PDF of the manual for your quick reference. I believe the settings to change the preout configuration is on pg. 24-26.

http://www.pioneerelectronics.ca/Sta...Manual1029.pdf

Outside of that it sounds like you need to reroute your RCA's and possibly purchase better RCA's. Is the static when you connected your MP3 player at the HU RCA end the same as with the HU connected? Also, is there noise when you only have the RCA cables connected on the amp side and disconnected at the HU? You mention earlier that you had noise even with the RCA's disconnected altogether, but is the noise worse with the RCA's connected? Sound's like you're still dealing mainly with an amp issue/speaker issue. Did you try a totally external speaker as I mentioned before?

Let us know and we can go from there.

Lyle

Lyle thank you for the continued guidance.

Just for shits and giggles I quickly made up a High Level Input line and used that for the rears instead of the RCA and boom everything was gravy. The rears were chugging along with the fronts. As per your recommendations I replugged the RCA's and checked in the control menu of the HU and effectively the AUX 2 was off so turned that back to on set the pre-out to fullrange. Even then there wasn't anything comming out of the rear speakers.

So I have concluded that the wiring to the rear speakers is ok because it works on the high level inputs, that the amplifier channels are ok because when using the RCA with the Ipod I can hear different music Fronts playing HU and rear playing Ipod. Also when switching the RCA sets the other set doesnt work ergo I switch the sets now rear only works and front doesn't work. This can only lead me to the conclusion that one set of my RCAs are scrap.

I went back and relistened to the static and now it is not that bad and I think it is at a livable level however, I will be once again taking apart all of the interior to reroute signal wires away from the power wire to the amp in an attempt to reduce the static. My question to you is, is it bad to use an RCA for my fronts and then the High Level Input for the rears?

Cheers,

Alex I.

Edit: Forgot to mention there is static whether the RCAs are disconnected from the amp or whether they are disconnected from the HU.

Hmmm... No that isn't bad, if that works for you. It's just typically the SQ from high level inputs is pretty poor.

If the noise is the same with the RCAs unplugged at the amp as it is plugged into the amp, then it sounds like an amp issue. Rerouting may not do much.

When you get a chance try hooking up a bookshelf speaker to your amp and see if it's still noisy. Also, try borrow an amp that you know works just to see. That will be the tell all of weather or not your amp is pooched.

Right now, that seams like the most likely senario. Could just be those RCA's too, I'm concerned that one connector pulled out. That is an easy fix to resolder a new one on to the board. Have you noticed a change in the sound if you wiggle the RCA inputs on your amp? This would indicate a poor connection or a short.

Lyle

Alright little update.

Took the whole interior apart redid everything. One side of the car has the power and the power on switch cables the other side has the speakers and the RCA's.

The static is still the same so I guess I am just going to have to suck it up and live with it. I even added a second ground to the HU, shortened my AMP ground by 50% applied copper paste and seperated the wires so that nowhere do RCA's or speaker wire touch power.

I tested also plugging speakers directly into the HU and they still exhibit the same static.

I was able to use the RCA's instead of the line, everytime I would take the negative off the battery the HU would reset itself to non-default settings:dunno:

Could it be a problem that I don't have an antenna, or is it just that my car generates alot of noise?