DiyMobileAudio.com Car Stereo Forum banner

1 - 20 of 31 Posts

·
Registered
Joined
·
218 Posts
Discussion Starter · #1 ·
I have a whine that is pretty evident in between songs and (of course) at volume 0. Without going into detail on the architecture of the system, I have isolated it to being present between the amp and speaker, i.e. coming into the speaker wire somewhere/somehow. When I hook a speaker up to the amp in the trunk it shows no whine, but it is definitely evident in the speakers up front when hooked to the same amp.

I know I am using not-fancy speaker wire (Home depot 4x16awg conductor primary copper wire, it was cheap and suited the application wonderfully with respect to running mid and tweet wires to each door in one jacket). I suppose the thin plastic wall of the speaker wiring I am using is allowing interference to enter? They are also in close proximity to the power cable (I shall move), as well as passing close by the car's power cluster in the lower left section of the dash.

My question here is, is there a good shielded speaker cable available at a good value?

Any other suggestions?

TIA
 

·
Registered
Joined
·
491 Posts
I have a whine that is pretty evident in between songs and (of course) at volume 0. Without going into detail on the architecture of the system, I have isolated it to being present between the amp and speaker, i.e. coming into the speaker wire somewhere/somehow. When I hook a speaker up to the amp in the trunk it shows no whine, but it is definitely evident in the speakers up front when hooked to the same amp.

I know I am using not-fancy speaker wire (Home depot 4x16awg conductor primary copper wire, it was cheap and suited the application wonderfully with respect to running mid and tweet wires to each door in one jacket). I suppose the thin plastic wall of the speaker wiring I am using is allowing interference to enter? They are also in close proximity to the power cable (I shall move), as well as passing close by the car's power cluster in the lower left section of the dash.

My question here is, is there a good shielded speaker cable available at a good value?

Any other suggestions?

TIA
Probably not your speaker cable. Move the ground on the amp or more than likley your picking up noise in your signal cables(RCA's). Don't run those along side of your power or remote wires. Wanna keep your RCA's as far apart from those wires as possible. I always run my RCA's down the other side of the car from the power and remote wires, as well as any factory wiring harnesses or power sources..
 

·
Registered
Joined
·
751 Posts
I had this problem too... My fix was to add a Neg bat to chasis cable (One of the "Big 3" steps)...
This was after I whent through the pain staking process of elimination diagnosing the Head Unit, RCA's, etc. to find that the noise was coming from my amp to speaker.

Where and with what gauge is your amp grounded? What gauge is your power wire?.. Alt whine solution varies from everyones unique settup...
 

·
Registered
Joined
·
27 Posts
Based on maxxx's description of the noise, it has been verified to be coming in after the amp's output's. RCA cables and ground wires should have no effect on it.
Start by verifying that your front speakers are neither shorted nor grounded(some amps will play with a shorted or grounded speaker wire).
Next, try running new wires outside the car to the crossover's
If the noise goes away, you will need to choose a different route for the wires
If it doesn't go away, try moving the passive crossovers (passive crossover's are noise magnet's)
If it still doesn't go away, you can try rerouting the wires between the crossover's and the speakers athough you probably won't have alot of flexibility there.
I have never needed to use a shielded speaker wire in my life.
 

·
Registered
Joined
·
25 Posts
Typically noise introduction is low voltage introduction. Therefore it will typically be ground or on the input stage of the amp, and the amp will therefore amplify it. It is very rare in today's higher voltage low level inputs for noise introduction to occur from an input interference, it is more likely a ground loop issues. While low level introduction can and does occur, it is most commonly a faulty RCA cable or shielding ground on the RCA jack.

Be sure all amplifier and trunk mounted equipment uses the same ground. Also, be sure that the battery ground is making an excellent connection. Then be sure to check all grounds to the chassis and motor.
 

·
Registered
Joined
·
27 Posts
For everyone that has discounted the maxxx's conclusion, how do you explain away this simple fact?

When I hook a speaker up to the amp in the trunk it shows no whine, but it is definitely evident in the speakers up front when hooked to the same amp.
 

·
Registered
Joined
·
25 Posts
Forum noob, double post... sorry!!!
 

·
Registered
Joined
·
25 Posts
For everyone that has discounted the maxxx's conclusion, how do you explain away this simple fact?
Because any in car RFI introduction will be so nominal it would not be audible on the output side. It MUST be amplified.
 

·
Registered
Joined
·
218 Posts
Discussion Starter · #9 ·
Many apologies, continued testing and my A-B'ing earlier was incomplete. It seems to be the amp. Will bench test and report any unsolved issues.

Thank you for all your input so far. Stay tuned!
 

·
Registered
Joined
·
27 Posts
Yeah, sometimes troubleshooting noise can be quite a chore. You try so many things, sometimes you overlook something else. Good luck moving forward.





Because any in car RFI introduction will be so nominal it would not be audible on the output side. It MUST be amplified.
That's a nice theory. However, nothing could be further from the truth. But don't take my word for it, get yourself a passive crossover and a mid and tweet. Then start "sniffing" around the underdash and other areas where factory wires are run with the crossover in your hand and not connected to anything else. In many cars you will find areas that create noise in the speakers even though they are not even connected to an amplifier:D.
 

·
Registered
Joined
·
25 Posts
Yeah, sometimes troubleshooting noise can be quite a chore. You try so many things, sometimes you overlook something else. Good luck moving forward.







That's a nice theory. However, nothing could be further from the truth. But don't take my word for it, get yourself a passive crossover and a mid and tweet. Then start "sniffing" around the underdash and other areas where factory wires are run with the crossover in your hand and not connected to anything else. In many cars you will find areas that create noise in the speakers even though they are not even connected to an amplifier:D.
The amplified output overpowers small introduced RFI like that. Place that same crossover right next to those wires hook it up to an amp, then tell me how much you hear it. The noise floor is too low after the amp.
 

·
Registered
Joined
·
751 Posts
Many apologies, continued testing and my A-B'ing earlier was incomplete. It seems to be the amp. Will bench test and report any unsolved issues.
Thank you for all your input so far. Stay tuned!
Apparently the OP seems to think it is the amp (one of the last/or first dredded steps in hunting down whine)...
This was my hunt for alt whine in this thread (most of the steps/process included as well as helpful tips from other members): http://www.diymobileaudio.com/forum/diy-mobile-audio/56291-alt-whine-ground-loop-hell.html
 

·
Registered
Joined
·
218 Posts
Discussion Starter · #14 ·
Good news. It was (not one but) two pairs of ****ty rca's that needed replacing. Whine not audible anymore. Much more work than I should have done to figure it out (I could swear I swapped them out earlier and not perceived a change), but anyways the upside of my extensive benchtesting is the piece of mind that all my components seem to be working quite well! Thanks for your input.
 

·
Registered
Joined
·
218 Posts
Discussion Starter · #16 ·
Bad news. I changed nothing and the whine came back as soon as I started the car. But get this: It is still there when the engine is off and key is not in ign position.

How can a whine that could no longer be detected after swapping rcas re-appear after the engine is started, AND NOT GO AWAY WHEN THE ENGINE/IGNITION IS TURNED OFF??? In other words, my whine-free existence was extremely short-lived, and I can't think of how to get it back.

I wish I knew what is triggering this. In the meantime I am fishing the rcas out of the garbage that I threw out last night...
 

·
Registered
Joined
·
25 Posts
Bad news. I changed nothing and the whine came back as soon as I started the car. But get this: It is still there when the engine is off and key is not in ign position.

How can a whine that could no longer be detected after swapping rcas re-appear after the engine is started, AND NOT GO AWAY WHEN THE ENGINE/IGNITION IS TURNED OFF??? In other words, my whine-free existence was extremely short-lived, and I can't think of how to get it back.

I wish I knew what is triggering this. In the meantime I am fishing the rcas out of the garbage that I threw out last night...
What kind of vehicle?

My first thought is possibly something is picking up RFI from the fuel pump circuit. But in many cases that feed is external. The pump will cycle on for 2 or 3 seconds before the car is started to purge air from the system. Then it will begin to run solid when the car is started, and in some cases it will run on until the car is completely shut down. In most cases I can foresee a fuel pump failure with my amp clamp and scope. Their patterns and RFI are telltale signs. If the RCAs are bundled against this feed, your noise may be being introduced there.

Also, how long has this system been installed? In other words, did this start happening right after the install, or has it culminated with time? What components are in the system? Specific HU and amps in particular.
 

·
Registered
Joined
·
218 Posts
Discussion Starter · #18 ·
interesting comments on the fuel pump issue, it is exactly what I thought might be going on. But now the whine doesn't seem to go away under any circumstance.

The whine has been there since the system was first assembled. At that time I moved rcas, power lines, and ground all around without avail. I lived with it for a while and now just getting back to experimenting and diagnosing it.

Again, after f'g around in my garage whine went away (coincidentally) with swapping-in of new rcas. Drove to work this morning, turned on the radio after pulling out of the driveway, and couldn't believe my ears. Whine-o to-die-now.

System is very complicated, but first I'll give you the core:

Panasonic DVD changer optical into Alpine PXA-H701
From h701, short rca leads into MC431.
****e Home Depot 16awg wire into doors up front. Active, no passives.
Additional 3' rca lead going from H701 into zapco line driver into 3.0x, bridged into sub
4awg Power coming through firewall, running on same side as left speaker leads. 4awg Ground to chassis near amps install.
No rcas travelling outside the rear install area.

I'll keep toying and let you know what I find.
 

·
Registered
Joined
·
82 Posts
Hmm I'm def interested in seeing how this pans out for you. I've got a whine in mine as well specifically with 3 or more RCA's plugged into the 4 channel amp. And it doesn't matter which of the 3 I have just that magic number. I'm going to have to do some re running as I have made 2 major rookie mistakes.

1. My car is a KIA 03, gift from my mother if I had my choice it woulda been a honda used for that matter LoL anywho, I ran the RCA's and ALL the speaker wires as one bundle up under the center console. That being said I need to go back this weekend and seperate those out.

2. My car is a KIA, the 2003 model specifically has a rear hatch under the rear seat for acess to the fuel pump for easier replacement. However, that hatch also has the harnes to the fuel pump thorugh it.....and I ran ALL the wires OVER that hatch....in the infamous words of homer, DOH!

Well we are all rookies at some point right???

Edit: OH and i'm messing with my system this weekend one way or the other.....it's getting fixed
 
1 - 20 of 31 Posts
Top