pauls350z

Hi,

I recently bought my 350z as an import from Japan into the UK and I quickly decided that the stock sound system was pants.

I have followed a few treads from various sites about the way to install a non-standard system.

So far, i have:

Pioneer Head Unit into:
- 1 Clarion Active Crossover:
High output connects to:
Input 1: Clarion 4 Channel Amp - powering:
- 2 Infinity Passive Crossovers into:
- 2 Infinity Mids
- 2 Infinity Tweeters
Low input connects to:
Kenwood Mono Sub Amp into:
- 1 Inifinty 10" Sub

- Input 2 of the Clarion 4 Channel Amp - powering:
- 2 Infinity Passive Crossovers into:
- 2 Infinity Mids
- 2 Infinity Tweeters

POWER - is direct from the battery routed down the left hand side of the car (passenger UK) and the earth is connected directly to the chassis, behind the driver seat.

AMPs - are behind the divers seat along with the SUB and rear crossovers.

PRE-OUTS (x2) - are run down the centre console

SPEAKER WIRE FOR FRONTS - are down either side and then run through the multi connect door connectors into the passive crossovers.

The sound is great - apart from engine interference - ggrrrrrrr

Can I call on you all to let me know a quick fix for this ?

Thanks in advance.

Paul

Spike100

^^ Hi Paul, …and welcome.

I think the fellows here should be able to help solve this problem for you.

I’ll start with the first questions:

1) Does the interference become worse as you increase the engine RPM’s?

2) Are you grounding your A/V components to a common point, or do you have multiple grounds? (Neither is necessarily bad, but it might help having this information)

--Spike

pauls350z

Hi Spike,

Thank you for your welcome and first response.

The 2 amps and active crossover share a common earth which is attached directly to the chassis.

The noise is apparent at tick over and gets worse when put into gear and then reved.

Thanks again

Spike100

Paul… If the interference becomes worse as you increase engine speed, it’s probably “alternator whine.”

“Alternator whine” is almost always cured by improving your grounds. The problem might come from any of the grounds (including a fault in your car’s charging system or the ground strap on your battery), or you may be experiencing a “ground loop” between the H/U and your amp. You may need to ground your H/U to the same point you ground your 2 amps.

Here is a link explaining this.

http://www.caraudiohelp.com/newslett...ator_whine.htm

I realize we are 6 hours off each other, so you probably won’t see this message until “your morning” which is actually “my evening.”

--Spike

pauls350z

When i first installed this, I grounded back to the battery and that was horrendous - hence the grounding to the chassis.

I do like the idea of grounding the headunit back to the same ground on the chassis. I did create my own ground by drilling into a panel and securing with a self tapping screw, so hopefully a good one !


I have the earthing cables running down the pre-out cables along side the 12v switch line to the amps, so I can use these quickly and a easily. However, do I need to totally disconnect the negative feed from the ISO connector and then rely on the ground that I created?

Many thanks again

Spike100

Re:> “I have the earthing cables running down the pre-out cables along side the 12v switch line to the amps, so I can use these quickly and a easily. However, do I need to totally disconnect the negative feed from the ISO connector and then rely on the ground that I created?”

I think you should definitely use the ground you created since you know this is good.

I may be missing the details in your setup (sorry if I’m dense here ), but reading your wiring configuration I’m thinking you may be getting interference from the RCA cables running from your H/U to your amps.

You may want to try swapping out your RCA cables.

--Spike

pauls350z

I have used these RCA cables on previous cars without a problem and they are very high quality - so i hope they won't be a problem

Are you suggesting that i change the cables or the route of the cables? I guess you make an interesting point as the drive shaft goes down the center console too. Should this really make a difference though?

I will try the following:

1. Ground the earth cable that runs down the RCA cables at both ends
2. Ground the H/U to the common ground that is shared with the AMP
3. Re-run the RCA's a different route:
choice 1: the same side as the 12v +
choice 2: the other side to the 12v +

Thanks

Paul

StreetOC192

iTrader: (7)

1. Ground the earth cable that runs down the RCA cables at both ends
**this may or may not make a difference. Is this wire meant to be used as a turn-on lead or is it a true drain wire? If it is a true drain wire, then you will want to ground on the headunit side only. If it is a wire that just happens to be piggybacked onto your rca's and is meant to be used as a turn-on lead, then grounding it will do nothing for your cause. If you are unsure the true purpose of this wire you speak of, perhaps a make/model of the rca cable you are using or a picture will allow us to decipher it for you.

2. Ground the H/U to the common ground that is shared with the AMP
**Ideally all of your ground wires will want to be as short as possible. The ground from headunit>chassis should only be about 6-8 inches, grounds from amp(s)>chassis should not be more than 2 feet.

3. Re-run the RCA's a different route:
choice 1: the same side as the 12v + **NOOOOOO
choice 2: the other side to the 12v + **YES

pauls350z

BTW 1

I will let you know th result

BTW 2

Odd - but Passenger Window stoped working after install - any idea's ?

Cheers

StreetOC192

iTrader: (7)

Since you ran the wire through the factory molex connectors, perhaps the connector wasn't clamped back tight. This happened to me after my install. Or you may have bent a pin in the connector while putting back together......this also happened to me.

pauls350z

Street -

1. Ground the earth cable that runs down the RCA cables at both ends
**this may or may not make a difference. If this wire meant to be used as a turn-on lead or is it a true drain wire?
The turn on lead is already being used to switch on the Amps - the blue wire. I also have a black wire avaliable (currently not used) i was thinking about grounding at both ends to try and stop interference.

If it is a true drain wire, then you will want to ground on the headunit side only. If it is a wire that just happens to be piggybacked unto your rca's and is meant to be used as a turn-on lead, then grounding it will do nothing for your cause.
Again, this is odd as I have RCA, Blue and Black cables, the blue is remote turn on and the black is unused

2. Ground the H/U to the common ground that is shared with the AMP
**Ideally all of your ground wires will want to be as short as possible.
The ground from headunit>chassis should only be about 6-8 inches, H/U is still using the -12v to the battery

Grounds from amp(s)>chassis should not be more than 2 feet.
Currently 2ft

3. Re-run the RCA's a different route:
choice 1: the same side as the 12v + **NOOOOOO Cool - thanks
choice 2: the other side to the 12v + **YES Great - thanks

pauls350z

re: passenger window

I have a feeling that i messed up the re-connect on the drivers side and this affected the passenger window. Trouble is, they are soooooo tight.

Gonna take it all apart on the weekend - roll on the weekend

you guys are great - thanks for the advise !

Spike100

Paul,

Forgive me if my “advice” doesn’t match what you actually intend upon doing this weekend.

I think taking some of the installation apart is a good idea. You can leave the amps, speakers, and crossovers in place.

For sure you want to pull the H/U and check all the wiring here. I remain suspect of the grounds and/or the RCA wires.

I think you are fairly expert and more knowledgeable than I am. I am replying to your thread mostly to gain interest from the many A/V experts that visit this Forum, and hopefully get their help to arrive at a solution. “Street” is one of the best we have here (he is smart and has helped a lot of my350z.com members).

Subscribing…

--Spike

StreetOC192

iTrader: (7)

Spike,
Thanks for the very generous compliment. But don't sell yourself short on your own knowledge. I read your posts........

Paul,
The easiest way to isolate if the alternator whine is being introduced via your rca's is to pull your rca cable out from where you have it running (I think you said along the center tranny tunnel?) Then connect it to the headunit and to the amps holding it up inside the car or draping it over the seats. This will ensure it is far enough away from any wiring under the carpet that might be introducing the noise.

If the whine goes away, then you KNOW it is being introduced through the rca's and you also now know that you need to route the rca's better being cautious of other wiring. Even the best rca's that cost hundreds of dollars are susceptible to noise if not run with caution.

If the noise does NOT go away during this test, then your noise is most likely being introduced via a bad ground either at the headunit or the amps. And the route your had taken with the rca's might be good.

Edit, just for reference I have my +12v and my remote turn on running down the passenger side door sill and my rca cables running down the driver side door sill. I took no particular cautions/shielding techniques, the rca's are running along side the factory wire loom. I am using relatively cheap Directed Audio Graphite series twisted pair rca's and I have no issue with alternator whine.

This is the cable I'm using, but I bought the 4-channel pair.......
http://www.electronicexpress.com/product?prod_id=14336

pauls350z

Spike / Street,

You guys are both full of great information and advice, I thank you both and can't wait for the weekend where I can try this stuff out.

This is the first forum that I have tried for my Z and I am sooooooo pleased that I picked this one

Cheers from the UK

I'll feed back after the weekend.

Thanks !!

Spike100

Paul, One more comment…

Street mentions something that I overlooked, and I think it could provide your solution. Street says (and i bolded the pertinent info): “I am using relatively cheap Directed Audio Graphite series twisted pair rca's and I have no issue with alternator whine.”

For sure follow the steps Street outlines in his message (Msg #14 on this Thread). That will definitely isolate the problem. You are going to need to pull the H/U anyway. Street’s diagnostic procedure matches what is suggested in the link posted in Msg #4.

I’m drilling this down to the RCA cables as the problem since I believe you have done the grounds correctly. Notice that Street is using twisted pair RCA cables.

My most sincere hope that you find a quick resolution this weekend. I know how frustrating this stuff can be.

--Spike

pauls350z

Update.....

I re-created my earth/ground
I shortened the lengh of the ground cable
I joined the H/U ground to the common ground with the amps

Still not sorted.

Unfortunatley, i ran out of time as the wife wanted to go shopping

Anyway, I now plan to re-run the RCA's down the driver-side of the Z (power on passenger side)

Will do this on the weekend.

Thanks

StreetOC192

iTrader: (7)

Thanks for the update. Sorry your efforts haven't paid off yet. Hopefully relocating the rca's will do the trick.

pauls350z

Update #2

Not good - but interesting...

I have re-run the RCA's down the drivers side of the car, so I now have the following:

12+ runs down passenger side
12- grounds direct to the bodywork on short earth (H/U and Amps)
12+ (remote) runs down one of the RCA's

RCA's run down the driverside

Long story but in short I have the same issue but I have found that I can turn this off.......

My Clairion AMP has 2 x RCA inputs, one of these is direct from the H/U and runs into Input 1, the other input comes from the High Pass from the Active Clarion Crossover. This is a 4 Channel Amp and powers 4 x Infinity Passives and then on to speakers.

I have found out today that I can run one of the RCA's into either of the inputs and get no interference.

So this means;

I can run RCA 1 (Fronts) into Input 1 on the Amp I get no interference
I can run RCA 2 (High pass Rears) into Input 1 on the Amp I get no interference
I can run RCA 1 (Fronts) into Input 2 on the Amp I get no interference
I can run RCA 2 (High Pass Rears) into Input 2 on the Amp I get no interference

However, if I have both connected at the same time i get interference.

I have also tried spliting the RCA's with no luck.

Getting annoyed but I am now running fronts and the sub until I get some more idea's.

Thanks in advance

Paul

pauls350z

BUMP