JapCarForum Cars, Cars, Cars! Car Audio/Video/Electronics/Security One for the Gurus - DC Whine!

One for the Gurus - DC Whine!

One for the Gurus - DC Whine!

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toxo
Posting Freak
4,843
24-09-2016, 09:05 AM
#1
Sorry for the essay but background is important with this problem...

The MR2 is a bit of a challenge when it comes to ICE as you're very limited on space. The boot is no good for anything, if you put amps or crossovers or any signal processors in there they have to get their signal past the engine which is a minefield of interference. I've got all my stuff in the front, on top of the spare wheel. This consists of a powercap (unnessecary I know but it looks cool!), some power distribution including digital voltmeter & ammeter, and 2 amps, a class A for the components and a class D monoblock for the subs. The components in the doors are Alpine DDDrive ones (old but good!) with seperate passive crossovers and the subs are a pair of Vibe 10" behind the seats in custom enclosures.

The problem I have is DC whine. There's some that's there all the time, and some that's rev-related. As far as I can tell it's only audible from the subs (which really shouldn't be able to reproduce it!) but I think that's probably because the capacitors in the crossovers for the components are smoothing it.

A problem in the MR2 is the power steering. Because it's at the other end of the car to the engine, it's driven with a massive great 12v motor instead of a belt driven pump. This generates loads of interference and I have tried my hardest to avoid it. None of my cables run within 8" of it and I have not run power and signal cables together. The constant whine gets louder the more you move the wheel, but the rev-related whine doesn't.

My power leads to the distribution block are all 4AWG with the grounding points freshly sanded upon installation. These are the same size as the main earth straps on the car.

I have noticed that the whine is a constant volume, so it must be introduced either at the amps or onto the signal cables that run to the speakers. However it's difficult to introduce interference into amplified cables, you normally pick it up at line level instead.

Confused! Suggestions?
Edited 05-11-2009, 06:50 PM by toxo.
toxo
24-09-2016, 09:05 AM #1

Sorry for the essay but background is important with this problem...

The MR2 is a bit of a challenge when it comes to ICE as you're very limited on space. The boot is no good for anything, if you put amps or crossovers or any signal processors in there they have to get their signal past the engine which is a minefield of interference. I've got all my stuff in the front, on top of the spare wheel. This consists of a powercap (unnessecary I know but it looks cool!), some power distribution including digital voltmeter & ammeter, and 2 amps, a class A for the components and a class D monoblock for the subs. The components in the doors are Alpine DDDrive ones (old but good!) with seperate passive crossovers and the subs are a pair of Vibe 10" behind the seats in custom enclosures.

The problem I have is DC whine. There's some that's there all the time, and some that's rev-related. As far as I can tell it's only audible from the subs (which really shouldn't be able to reproduce it!) but I think that's probably because the capacitors in the crossovers for the components are smoothing it.

A problem in the MR2 is the power steering. Because it's at the other end of the car to the engine, it's driven with a massive great 12v motor instead of a belt driven pump. This generates loads of interference and I have tried my hardest to avoid it. None of my cables run within 8" of it and I have not run power and signal cables together. The constant whine gets louder the more you move the wheel, but the rev-related whine doesn't.

My power leads to the distribution block are all 4AWG with the grounding points freshly sanded upon installation. These are the same size as the main earth straps on the car.

I have noticed that the whine is a constant volume, so it must be introduced either at the amps or onto the signal cables that run to the speakers. However it's difficult to introduce interference into amplified cables, you normally pick it up at line level instead.

Confused! Suggestions?

Sparkystav
Administrator
14,683
24-09-2016, 09:11 AM
#2
do you have a decent head unit?

when i had a cheap ebay one i had the same, as soon as i switched to a decent Alpine one it went

OutlawJapClub Admin Team
Sparkystav
24-09-2016, 09:11 AM #2

do you have a decent head unit?

when i had a cheap ebay one i had the same, as soon as i switched to a decent Alpine one it went


OutlawJapClub Admin Team

toxo
Posting Freak
4,843
24-09-2016, 09:13 AM
#3
Panasonic Double-din CD/Tape combo. It's not bad but it wasn't expensive by any means Smile I don't think the head unit can be introducing the whine though cause it doesn't vary with volume. Plus I've tried running the HU off an isolated 12v bench supply with the amps still running off the car and it made no difference.
toxo
24-09-2016, 09:13 AM #3

Panasonic Double-din CD/Tape combo. It's not bad but it wasn't expensive by any means Smile I don't think the head unit can be introducing the whine though cause it doesn't vary with volume. Plus I've tried running the HU off an isolated 12v bench supply with the amps still running off the car and it made no difference.

FirebirdPhil
Posting Freak
7,101
24-09-2016, 09:24 AM
#4
I had that same issue turned out to be the cables going into the amp were run to close together as they came through into the boot area, separating them solved the problem instantly.

"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
FirebirdPhil
24-09-2016, 09:24 AM #4

I had that same issue turned out to be the cables going into the amp were run to close together as they came through into the boot area, separating them solved the problem instantly.


"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"

toxo
Posting Freak
4,843
24-09-2016, 09:32 AM
#5
I only run signal cables through the bulkhead though, all my power feeds are taken from inside the frunk and they never run with signal cables...
toxo
24-09-2016, 09:32 AM #5

I only run signal cables through the bulkhead though, all my power feeds are taken from inside the frunk and they never run with signal cables...

Bandit
Posting Freak
6,464
24-09-2016, 09:39 AM
#6
Have you got any noise suppressors fitted mate? You can get them for most things, like alternators,electric motors and other things? You can get ground loop isolators from most car accessory shops and they do work quite well? like one of these CLICK ME? and this one for the alternator CLICK ME?
:biggrin:

Lexus IS200 Sport Navigator (Now being stripped again) :blink:


Now Don't Forget The REP!!!
Bandit
24-09-2016, 09:39 AM #6

Have you got any noise suppressors fitted mate? You can get them for most things, like alternators,electric motors and other things? You can get ground loop isolators from most car accessory shops and they do work quite well? like one of these CLICK ME? and this one for the alternator CLICK ME?
:biggrin:


Lexus IS200 Sport Navigator (Now being stripped again) :blink:


Now Don't Forget The REP!!!

toxo
Posting Freak
4,843
24-09-2016, 09:42 AM
#7
I have tried running a supressor on the head unit's power supply (and like I said above I've run the head unit on a clean bench DC supply) and it's made no difference. Have to say I haven't tried a ground loop isolator yet, and I have noticed that I can run the head unit with no -ve connection, so it must be grounding through something else...
toxo
24-09-2016, 09:42 AM #7

I have tried running a supressor on the head unit's power supply (and like I said above I've run the head unit on a clean bench DC supply) and it's made no difference. Have to say I haven't tried a ground loop isolator yet, and I have noticed that I can run the head unit with no -ve connection, so it must be grounding through something else...

Bandit
Posting Freak
6,464
24-09-2016, 11:12 AM
#8
Think if it was me mate i'd load the alternator with suppressors trying different ratings which should stop the rev related whine? then move through to the amp with a ground loop isolator, Have you tried the system without the power cap to see if that's got anything to do with it? And wonder if you could use a suppressor on the pas motor too to try and kill any interference? or like you say it could be the head unit picking up an inferior earth from somewhere?

Its so annoying when you cant track it down as it ruins a good setup :confused:

Lexus IS200 Sport Navigator (Now being stripped again) :blink:


Now Don't Forget The REP!!!
Bandit
24-09-2016, 11:12 AM #8

Think if it was me mate i'd load the alternator with suppressors trying different ratings which should stop the rev related whine? then move through to the amp with a ground loop isolator, Have you tried the system without the power cap to see if that's got anything to do with it? And wonder if you could use a suppressor on the pas motor too to try and kill any interference? or like you say it could be the head unit picking up an inferior earth from somewhere?

Its so annoying when you cant track it down as it ruins a good setup :confused:


Lexus IS200 Sport Navigator (Now being stripped again) :blink:


Now Don't Forget The REP!!!

toxo
Posting Freak
4,843
24-09-2016, 11:17 AM
#9
I'll gladly put a suppressor on the alternator if you can find me a 110A one Wink PS motor is fused at something silly high as well... it is epic big, like 2L bottle of coke big. You're not the first to suggest removing the power cap from the equation so I will try that this weekend to see if that's got anything to do with it. I'll grab a ground loop isolator at the weekend as well and see what happens.
toxo
24-09-2016, 11:17 AM #9

I'll gladly put a suppressor on the alternator if you can find me a 110A one Wink PS motor is fused at something silly high as well... it is epic big, like 2L bottle of coke big. You're not the first to suggest removing the power cap from the equation so I will try that this weekend to see if that's got anything to do with it. I'll grab a ground loop isolator at the weekend as well and see what happens.

Bandit
Posting Freak
6,464
24-09-2016, 11:27 AM
#10
Worth a try mate :biggrin:

If i think of anything else to try i'll post it up :thumbup1:

Lexus IS200 Sport Navigator (Now being stripped again) :blink:


Now Don't Forget The REP!!!
Bandit
24-09-2016, 11:27 AM #10

Worth a try mate :biggrin:

If i think of anything else to try i'll post it up :thumbup1:


Lexus IS200 Sport Navigator (Now being stripped again) :blink:


Now Don't Forget The REP!!!

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