Technical Dualogic gearbox causing static/hissing right tweeter? HELP?!?!

[Barney2017]

Hi,

This is my first time posting on here, so please forgive me if I am missing anything or posting the wrong way - new 2013 Fiat 500 Sport owner.

My issue is really quite bizzare, my right tweeter (and only that speaker) is creating this weird, static/electronic hissing noise even when the stereo is off.

This hissing noise isn't apparent all the time, it only can be heard when the dualogic gearbox changes gears or when I am reversing or going reallyyyyy slowly forward (same in both auto shift mode and manual mode). I have checked that the noise isn't coming from the engine bay and no it definately isn't the servo - I know this because the hissing noise goes away when I cover the right tweeter

Otherwise, weird static hissing noise aside, everything is perfect! None of the other speakers have such an issue either (and everything works on the stereo) - just the right front tweeter is hissing (it is literally like a fairly high pitched electric kinda noise).

Called a local radio shop, they said it could be the radio that is faulty...But I find that hard to believe when all aspects of the radio itself work??? They said, oh, we can sell you some great tweeters and rewire it to see if it fixes the problem...sounds like they are just trying to sell me ****...

I have literally only had this car for less than 12 hours, and really like it otherwise. Please help me work this out...Another forum created mentioned looking at the earth points under the bonnet? - See old 09 forum comment

Thanks,

Any help is very much appreciated...Me stressing...

 

[Barney2017]

Just checked again, and the noise is coming from both the right tweeter and right speaker, those two only...

 

[jrkitching]

Hi

Hello and welcome to the forum :wave:.

This is my first time posting on here, so please forgive me if I am missing anything or posting the wrong way

Generally there should be only one thread per active topic. Instead of reviving a very old thread, it can sometimes be better to start a new thread and include a link to the old one; I've edited your first post to show how this is done.

 

[John202020]

Just checked again, and the noise is coming from both the right tweeter and right speaker, those two only...

Are you absolutely sure its just the right front and no others? Is it the same regardless of source, IE. radio, CD, Aux/USB in? if yes to both its the head unit, most likely.

Noise coming in from the power feed would effect all channels, noise coming in on the audio would effect both front and rear but possibly only one side(though less likely just one side), its possible the rear speakers are (poor for want of a better term) and the noise is there but cannot be heard.
Noise coming from static or a spark would also effect all channels.
In theory noise could be induced on the cable from the head unit to the speaker(bundled in with all the others) the only way to check is to run a new wire from the rear of the radio to the speaker and see if the noise is still present( with the original disconnected from the radio)

 

[Barney2017]

Are you absolutely sure its just the right front and no others? Is it the same regardless of source, IE. radio, CD, Aux/USB in? if yes to both its the head unit, most likely.

Noise coming in from the power feed would effect all channels, noise coming in on the audio would effect both front and rear but possibly only one side(though less likely just one side), its possible the rear speakers are (poor for want of a better term) and the noise is there but cannot be heard.
Noise coming from static or a spark would also effect all channels.
In theory noise could be induced on the cable from the head unit to the speaker(bundled in with all the others) the only way to check is to run a new wire from the rear of the radio to the speaker and see if the noise is still present( with the original disconnected from the radio)

Hi,

I really appreciate you helping me out here.

The noise first off, is not apparent when the ignition is switched to the first position, it is only when the initiation of the dualogic gearbox is made (i.e. when the key is turned to get the car going) then the static like sound occurs when idling, it goes away once you get up to speed, but briefly comes back when the use of paddleshifters or the car shifting to change gears occurs - otherwise, the sound doesn't occur, when, say, going 30 without shifting or the car shifting gears - hence my thought that there is some static/frequency coming from the dualogic gearbox that is coming through the speakers.

All speakers, right speaker and tweeter included produce perfect sound - I am an audiophile at heart. So, they work perfectly fine, they just make this static sound when the dualogic gearbox is used. The car is a one owner car, full service history, just over 20,000miles.

Note, that I had a complete pre purchase inspection done a week ago before purchasing the car. The report was great, so I bought the car, got it serviced and then shipped to me. The service was done by the stealership that has serviced it since new (I know...lol). Is there anything they could have tinkered with during the oil change, coolant change and rotor & brake replacement to cause this, as the pre purchase inspection was very thorough and would have mentioned something if heard. I am going to contact the stealership that serviced it to ask if they heard such a sound???

I am not too car savvy, but fairly tech savvy, could it be a regulator thing? Or some kind of power feed issue? - would find hard to believe though, as one would assume that it would cause all speakers to go all hissy (fit...lol) and staticy? Saw a forum that mentioned that "the amps are grounded together on the driver's-side wheel well stud" - could this be the cause, as the brakes and rotors were replaced, as well as the wheels being rotated etc during the service i.e. after the pre purchase inspection (which came up clean)???

Thanks so much, any further help is oh so very much appreciated

 

[John202020]

The issue I'm having problems understanding is why its just one channel, does the car have a separate amplifier or is it all built into the radio unit(anyone?)

 

[jrkitching]

The issue I'm having problems understanding is why its just one channel, does the car have a separate amplifier or is it all built into the radio unit(anyone?)

My guess is that it's picking up interference somewhere in the wiring for that channel (the wires are basically acting as crude antennas); probably just poor shielding & suppression. Annoying, and potentially quite hard to troubleshoot.

Unless you have interscope, the amplification will be in the factory fit head unit, but like any stereo there will of course be discrete amplification circuits for left & right channels.

 

[Mercky]

get the correct tool (halfords could help) and pull out the head unit and reverse the speaker connections - that'll tell you if the head unit / amp is at fault or if its a wiring or pick up issue

 

[John202020]

My guess is that it's picking up interference somewhere in the wiring for that channel (the wires are basically acting as crude antennas); probably just poor shielding & suppression. Annoying, and potentially quite hard to troubleshoot.

Unless you have interscope, the amplification will be in the factory fit head unit, but like any stereo there will of course be discrete amplification circuits for left & right channels.

My thinking was if it's an external amplifier then it's quite possible to pick up interference on just one input wire(out of the 4 inputs, 5 if there's a sub) due to poor shielding, that could explain the single side issue but if it's built in then the chances of a single input to the amp chip is far less.

Are there any other audio input connections ? from say a un used aux in or unused Bluetooth input whilst they may not be being used noise could creep in on those too, earthing any unused inputs would stop this if that's what's causing it, as JR says tracing it can be very hard and time consuming.

 

[Barney2017]

My thinking was if it's an external amplifier then it's quite possible to pick up interference on just one input wire(out of the 4 inputs, 5 if there's a sub) due to poor shielding, that could explain the single side issue but if it's built in then the chances of a single input to the amp chip is far less.

Are there any other audio input connections ? from say a un used aux in or unused Bluetooth input whilst they may not be being used noise could creep in on those too, earthing any unused inputs would stop this if that's what's causing it, as JR says tracing it can be very hard and time consuming.

Hi,

It does have Blue&Me Bluetooth system which I would assume runs all of the time. However, if it were to be Bluetooth related, it simply wouldn't explain why the noise occurs when the dualogic gearbox servo is being used (as the servo is used to help shift gears and with starting off etc right?). Any thoughts as to whether it is servo related? As the servo helps to shift gears and the sound only occurs when the servo is being initiated to change such gears, or when e.g. doing a hill start with the dualogic gearbox i.e. while it is using the servo.

The sound wasn't there when I got the pre-purchase inspection done, and the only thing that has been changed since the pre purchase inspection just under two weeks ago is stuff in the engine bay - being when it was serviced.

Have contacted the stealership to ask mechanics and their thoughts, and have asked them to do some digging (they have been really good). They also mentioned that there was a grounding point in the A-pillar(s). As I have previously said, I am no mechanic at all...quite the opposite so just doing the research I can...

I do really want to get it sorted. I just can't understand how a routine oil change, coolant change etc can cause such an issue. It is really annoying, so am really hoping that you guys can help me get the bottom of this.

Do you guys reckon it is stereo or mechanical related? Is the next step is to take it to a mechanic as well as this forum digging/researching? - me personally can't understand how it can be stereo related. The stereo has no issues (everything works perfectly),So yeah, a bit lost...Please help me get to the bottom of this

Also, no other phones or cables connected - have already checked that No sub, just the basic stereo I think.

If you guys can help me get to the bottom of this, my god, I will most definitely be donating money to this site (amazing how many Fiat 500 owners there are!...although, did I make the wrong decision to buy one...starting to sound like nightmare...).

Thanks

 

[Barney2017]

get the correct tool (halfords could help) and pull out the head unit and reverse the speaker connections - that'll tell you if the head unit / amp is at fault or if its a wiring or pick up issue

I am not car savvy enough to remove the stereo (think of a noob, then think about one 10 times over...that would be me with cars). I can troubleshoot using the internet fairly well as I am tech savvy I guess. I live in a fairly rural place (in little ol' New Zealand!) so no audio places nearby. How could it be the headunit when the only thing(s) changed since the pre purchase inspection was in the engine bay?

Thanks and I really appreciate everyone's time spent on this

 

[John202020]

If it is the servo(assuming its a electric motor driven one not hydraulic) perhaps a suppressor could be fitted? could be as simple as a couple of capacitors to earth?

 

[ArthurM]

Hi Barney 2017. Firstly welcome to the forum. I think the Dualogic "issue" could well be a red herring. My first thought was that the radio needed retuning to a different station (try retuning). The Fiat electrics are really something else. I noted that you live in a rural area in NZ ,could you be picking up interference from perhaps a CB radio transmission. I would retune the radio as a first. Please keep the forum updated. As a second thought I could not imagining the previous owner putting up with this so the solution may not be too complicated

 

[Barney2017]

Hi Barney 2017. Firstly welcome to the forum. I think the Dualogic "issue" could well be a red herring. My first thought was that the radio needed retuning to a different station (try retuning). The Fiat electrics are really something else. I noted that you live in a rural area in NZ ,could you be picking up interference from perhaps a CB radio transmission. I would retune the radio as a first. Please keep the forum updated. As a second thought I could not imagining the previous owner putting up with this so the solution may not be too complicated

Hi,

Alrighty, I have retuned the radio, made sure all of the driving speed audio increase, satellite etc stuff is turned off. That didn't seem to make a difference. When I picked up the car (from a location 2+ hours away - central/town area) the noise was still there, so I don't think it could be a CB radio transmission. I also reset the stereo, again no change in noise - still there, and still in tune with when I shift gears (i.e. when the servo I presume kicks in). I am hoping that it isn't too complicated.

What are your next thoughts? - I thought about using my phone mic decibel reader to try and confirm as to whether there is any sound coming from the other speakers?

Please, everyone, keep posting thoughts, it is really helping, the more the merrier

I really appreciate all of your time spent too everyone, genuinely.

 

[Barney2017]

If it is the servo(assuming its a electric motor driven one not hydraulic) perhaps a suppressor could be fitted? could be as simple as a couple of capacitors to earth?

Hi,

It has the dualogic gearbox (5 speed) - which according to wiki uses a, I quote "electrohydraulic servo".

I am not too car savvy/car minded, my understanding from what you state, that it could just require some "capacitors to earth". I don't know much as I say, but would that affect other stuff that uses ground (i.e. starting the car up etc?). Are there any suppressor out there for this "issue"?

In regards to a suppressor, if it is the servo - as I say, the sound only comes on when I am either going slow i.e. 1st gear (up to 10 or so kmh), or reversing (so slow too lol), otherwise, the sound goes away when going fast enough AND not shifting (me or gearbox), then it can be heard again through the right tweeter and speaker briefly as I shift or the car shifts - so, yeah, the only stuff that has been changed since the inspection is a coolant change, oil & filter, brakes (pads and rotors at the front) and the wheels have been removed - heard that there was a ground for the amp according to another forum (quoted in case any use...unsure to validity of it but yeah)- " the amps are grounded together on the driver's-side wheel well stud."

Could this have been affected when the brakes were done and wheel removed?

Thanks,

Otherwise, only other thought is that the aerial wasn't attached when the car was received - radio reception works fine, put the aerial back in when I got it (have already checked with or without aerial for if it changes anything). I am unsure how long it had the aerial sitting in the boot but yeah, may as well mention it

Thanks again,

Really appreciate this

 

[ArthurM]

Hi. If it is not a tuning issue( although I still think it is) ,the other thing could be " loose " wires to the speaker, again you have probably already checked. Must admit it's had me thinking. You appear to have a good knowledge of audio which is above my level. Best of luck. I had another thought. I bet when the garage did the service they disconnected the battery. Reading posts in the forum disconnecting the battery can cause some most unusual consequences(cannot recall hissing noises ).Have a look on the forum re battery posts. Hopefully someone else on the forum will be able to advise further.

 

[ArthurM]

Hi Barney2017. Just reading through your thread again and looking at your last post regarding the aerial not being attached, it now seems to me that the problem was there before you bought the car. My only suggestion now would be for you to consult an auto electrician. You will love your little car when it is fixed.

 

[John202020]

Costs nothing, disconnect the battery for 10 mins and reconnect?

 

[Barney2017]

Costs nothing, disconnect the battery for 10 mins and reconnect?

Will give that a shot and see how it goes. By the way, the website was down for me for like 2 days? - was it offline for anyone else? Thanks

 

[Barney2017]

Hi Barney2017. Just reading through your thread again and looking at your last post regarding the aerial not being attached, it now seems to me that the problem was there before you bought the car. My only suggestion now would be for you to consult an auto electrician. You will love your little car when it is fixed.

Hi,

Yep, I am going to disconnect the battery, see if that does anything. From there, auto electrician or car audio technician will be next.

Any other thoughts people?

Thanks