BlueMusic Humming

Antiguakidd

Antiguakidd

Member
I installed a BlueMusic Bluetooth adapter in my A2 a couple of weeks ago. Plugs into the back of the radio (Concert 2)


Tested it before I slid the radio back into place and all was well, but I didn't have the engine running. It seems now that if the engine is running then I get a high-pitched humming from the speakers in the rear of the car. This happens whether the radio is on or off.

If I only have power on (no engine running) then the humming stops.

Any ideas?
 
Evening,

I’ve come across this before and this type of issue is generally either an intermittent speaker connection or an earthing fault somewhere. I actually had a similar issue with my rear left speaker and tweeter after I conducted the Bose retrofit. Annoyed me for many days until I realised isn’t was one of the line-out (rear left) pins was loose in the black 20 pin head unit connector. it was quickly rectified but not before I went through checking the whole retrofit first as I thought I had done something wrong. Turned out I didn’t fortunately!

I would remove the head unit again and check that all pins are fully seated into their connector. Also check the wiring for any chaffing which has caused bare wire. As I’ve not fitted one of these BlueMusic modules before can you co firm that it requested a dedicated ground supply. If so where did you take it to as it found be a weak ground too.

It’s obviously not easy to diagnose exactly what is wrong in your vehicle but happy to have a look if you’re in the Chelmsford area as I’m heading that way tomorrow afternoon. I’m sure it all be something simple, usually is!

Kind regards,

Tom
 
Antiguakidd said:
I installed a BlueMusic Bluetooth adapter in my A2 a couple of weeks ago. Plugs into the back of the radio (Concert 2)


Tested it before I slid the radio back into place and all was well, but I didn't have the engine running. It seems now that if the engine is running then I get a high-pitched humming from the speakers in the rear of the car. This happens whether the radio is on or off.

If I only have power on (no engine running) then the humming stops.

Any ideas?
Click to expand...
Is the noise only audible on the rear speakers? Adjust the fader, 100% front to 100% rear to check.
If it is only on the rears, it's, probably, noise on the line outputs, (low level signals), to the rear speaker amplifier. Please confirm either way.
Mac
 
2work said:
Evening,

I’ve come across this before and this type of issue is generally either an intermittent speaker connection or an earthing fault somewhere. I actually had a similar issue with my rear left speaker and tweeter after I conducted the Bose retrofit. Annoyed me for many days until I realised isn’t was one of the line-out (rear left) pins was loose in the black 20 pin head unit connector. it was quickly rectified but not before I went through checking the whole retrofit first as I thought I had done something wrong. Turned out I didn’t fortunately!

I would remove the head unit again and check that all pins are fully seated into their connector. Also check the wiring for any chaffing which has caused bare wire. As I’ve not fitted one of these BlueMusic modules before can you co firm that it requested a dedicated ground supply. If so where did you take it to as it found be a weak ground too.

It’s obviously not easy to diagnose exactly what is wrong in your vehicle but happy to have a look if you’re in the Chelmsford area as I’m heading that way tomorrow afternoon. I’m sure it all be something simple, usually is!

Kind regards,

Tom
Click to expand...
Hi Tom,

Thanks for such a quick response. It did ask for an earth connection, I connected to the little screw the the side of the connectors in the back of the radio. I would've thought if it was something to do with the earth that it would be constant. The fact that it is only happening when the car is running seems odd to me, and hopefully can help identify the cause (or at least narrow it down)

Thanks for the offer for tomorrow, but I'm out all day at work.
 
PlasticMac said:
Is the noise only audible on the rear speakers? Adjust the fader, 100% front to 100% rear to check.
If it is only on the rears, it's, probably, noise on the line outputs, (low level signals), to the rear speaker amplifier. Please confirm either way.
Mac
Click to expand...
Will have another check, but I did try that. Seems to be only on the back, but even with the fader all the way to the front, I still get a buzzing
 
Hi, I think the problem is with the rear speaker amplifier. It should only be on, when the radio is on.
I'm guessing the hum stops when the ignition is off, or key is out?
Is the radio Concert I or II?
Unplug the amp to confirm. It's in the underfloor compartment, UK passenger side.
When you had the radio out, did the wiring look good, not messed about with?
Mac.
 
PlasticMac said:
Hi, I think the problem is with the rear speaker amplifier. It should only be on, when the radio is on.
I'm guessing the hum stops when the ignition is off, or key is out?
Is the radio Concert I or II?
Unplug the amp to confirm. It's in the underfloor compartment, UK passenger side.
When you had the radio out, did the wiring look good, not messed about with?
Mac.
Click to expand...
Just FYI it's UK driver side on mine.
 
Here's the circuit for the radio to rear amp connections.
This is for non Bose, so let me know if yours is Bose.
The supply is always on, and the switched 12 volts from the radio brings the amp out of standby.
Could post the adapter cable, fitting instructions for the BT adapter? Might give a clue, as the line outputs to the rear amp are on the same connector as the CD/BT, the larger connector, at the top of the three on the radio.
Mac.
Screenshot_20240424-191943.png
 
I have a similar problem on both my Audi, and Rover.
On the Audi, the Yatour changer gives a hum/whine only when I plug my phone into it via the 3.5mm jack

On the Rover 800, it is a little more complicated:
Head Unit, Alpine CDA9812RB using all 3 phone outs: 1 to Sub amp and speaker, the other 2 to the Kenwood 4 channel amp mounted in the boot, under the rear parcel shelf.
This feeds the 4 speakers.
2 in the front door, Inphase component 6 1/4" with separate crossover.
2 in the rear shelf, Pioneer 8" 3 way.

All the phono leads run up the middle of the car, and into the amp. The output of these then goes to the speakers. The rears, obviously a short lead. The fronts, the high quality speaker cables (untwisted) go to the front down the centre and connect into the standard Rover loom to feed the front speakers.

I only get horrible high pitched whine from the front, and only when connected to the Amp. And only when driving, less detectable when stationary. Under the head unit is the Rover SRS air bag control module.

Before I pull the entire interior out (seats and carpet) I am looking for inspiration in what to change with the leads. Am I looking at the phono input, or the speaker amplified output? and what is the best solution?

I am open to suggestions!!
 
On the Audi, when the phone is connected, via the jack, is the phone also connected to a charging lead?
On the Rover, how many inputs does the amp have, and how many are you using?
Mac
 
AndyP said:
Not sure but definitely driver side on my RHD. Passenger side has all the normal ECU & relay gubbins.
Click to expand...
Obviously I got the location wrong. I assumed it was in with the ECU etc, not the other side.
Sorry for the error, and noted for next time.
Mac
 
PlasticMac said:
On the Audi, when the phone is connected, via the jack, is the phone also connected to a charging lead?
On the Rover, how many inputs does the amp have, and how many are you using?
Mac
Click to expand...
On the Audi, there is a charge lead plugged in to the phone. i saw your comment about USB chargers earlier, and I will see if it happens when I remove the charge lead. And try that trick on the Rover
The Rover, the Amp is a 4 channel amp IIRC, will check when I get home. All the inputs are also used IIRC.
 
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