Intermittent high pitch buzz

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James-TT

CarAudio.com Newbie
Hello all,

I’m new to this forum and start off with a problem I need help with, so sorry for that.

I have installed a sound upgrade in the TT consisting of Hertz 2way in the doors, and a JL audio Subwoofer in the boot. These are running from a 4 channel amp and a mono amp. The source is from Apple CarPlay via a PX6 android unit.

My problem is I have an intermittent very high pitch buzz coming from both door speakers and tweeters. It happens roughly every 20 seconds and lasts for 5/6 seconds at a time then goes away.

The engine needs to be on for this to happen.

So far I have double checked my amps ground, both amps are in a splitter block then a single ground to the chassis.

I’ve unplugged the RCAs from the HU, but the noise remains.

I’ve unplugged the RCAs from the amp, but the noise remains.

Unplugging the RCAs doesn’t get rid of the intermittent buzz, but it is quieter.

the only way I can have the HU on without the buzz is when the engine is off.

I’m out of ideas.

tia

James.
 
Yeah those Chinese cheap android head units are not known to be very good and have issues like the one you are describing. Quite a few people across a few forums have had this issue, sometimes they can fix it sometimes they can't and they end up dumping them on eBay or locally and buy something from a name brand like Pioneer, Kenwood, Sony, Alpine and what not.

Sadly it is just how it is with those units. Very little QC and very cheap components.

Couple things you could try is to ground the head unit itself with it's own ground wire to a spot behind the dash and ground the rca's as well just in case. If those don't work might just have to go back to square one and find a different head unit.
 
Yeah those Chinese cheap android head units are not known to be very good and have issues like the one you are describing. Quite a few people across a few forums have had this issue, sometimes they can fix it sometimes they can't and they end up dumping them on eBay or locally and buy something from a name brand like Pioneer, Kenwood, Sony, Alpine and what not.

Sadly it is just how it is with those units. Very little QC and very cheap components.

Couple things you could try is to ground the head unit itself with it's own ground wire to a spot behind the dash and ground the rca's as well just in case. If those don't work might just have to go back to square one and find a different head unit.

I wouldn’t say at over £300 it was cheap, but the reason I didn’t go for one of the named brands like those off the shelf in Halfords, is because these units are shaped to fit exactly where the OEM HU was, and imo just look better.
I do have a Sony laying about, I’ll plug it in and see if the issue goes.

thanks

James.
 
Everything is expensive over there compared to the US though. While you might spend 300 pounds for it here it is maybe a 100-150 at most head unit or even cheaper in some cases.

Not trying to be rude or anything. Just stating that they are cheaper for a reason.

I would try the grounds first before swapping out. Yes they make those for a direct fit but that is why there is mounting adapters out there as well. Good luck!
 
Everything is expensive over there compared to the US though. While you might spend 300 pounds for it here it is maybe a 100-150 at most head unit or even cheaper in some cases.

Not trying to be rude or anything. Just stating that they are cheaper for a reason.

I would try the grounds first before swapping out. Yes they make those for a direct fit but that is why there is mounting adapters out there as well. Good luck!

Thank you, I’ll try those things you mentioned first, then I’ll try a different HU.

James.
 
Yeah those Chinese cheap android head units are not known to be very good and have issues like the one you are describing.
I doubt it is the HU at fault. Disconnecting the RCAs at HU and amplifier would have solved the issue.
I do have a Sony laying about, I’ll plug it in and see if the issue goes.
If disconnecting the RCAs from the amp does not solve the issue, it is the most likely the amp is having an issue. With the RCAs unplugged, touch a wire from the amp ground to the outer sleeve of the amp's RCAs. If it works, make the tap permanent.
 
Depending on exactly where you have the amplifiers mounted in relation to the fuel tank. You could also have a radiated noise problem coming from the fuel pump. ( in some cars, the fuel pump actually turns on and off while the car is running. ) I had this on one of my cars about 15 years ago. If my amplifier was about 2 inches above the truck floor it was fine. Any closer and their was noise. I fixed it by building a amplifier rack from scrap wood and carpet left over from my subwoofer box.
 
Depending on exactly where you have the amplifiers mounted in relation to the fuel tank. You could also have a radiated noise problem coming from the fuel pump. ( in some cars, the fuel pump actually turns on and off while the car is running. ) I had this on one of my cars about 15 years ago. If my amplifier was about 2 inches above the truck floor it was fine. Any closer and their was noise. I fixed it by building a amplifier rack from scrap wood and carpet left over from my subwoofer box.

The amps are in the boot/trunk on the thick foam/polystyrene insert that comes with the TT. I’ll include a picture, but I must mention, I didn’t have enough brown cable for the ground, so it’s brown to the distribution box then red to the amps (I figured the amps don’t know what colour the insulation is)
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527C5BB4-3A6B-49FB-A2BE-E1A90D2C7176.jpeg
 
Nice layout. But sometimes noise can come from the oddest places. Does it do it with the stereo off? Radiated noise problems can effect the speaker wires themselves. I have seen a tweeter with a speaker wire connected to it be noisy, even though it was not connected to anything.
 
Nice layout. But sometimes noise can come from the oddest places. Does it do it with the stereo off? Radiated noise problems can effect the speaker wires themselves. I have seen a tweeter with a speaker wire connected to it be noisy, even though it was not connected to anything.

Thank you.
Yes it does make the noise with the HU off.
I’ve actually used the OEM speaker wire, I removed the pins from the stock amp and connected them to the outputs on the crossovers.
I think I will try surface laying some new cable from the amps to the doors and tweeters to see if that’s the issue.
I would try a new RCA, but I think I’ve eliminated that as an issue as the sound is still there, although quieter when they’re unplugged.
I’ve used the same ground point that the HU and OEM amp used and getting no resistance on the digital meter when I tested it.
I have a spare 6x9 laying about that tomorrow I will test each channel on the amp with a short bit of speaker wire to see if I get the same noise through it.
apart from this noise, the system sounds great.

What’s weird to me is it’s not a constant buzz, like alternator whine, this is roughly every 20 seconds for about 5 seconds, then it repeats. like something is turning on and off.
 
Weirdly, the rear speakers are also making the intermittent buzz, these aren’t even running off my amp, they are on the stock amp. I unplugged them from the HU and they still buzz.
I’m currently sharing the ground point with my amps and the OEM amp, I’ll try relocating that ground.

with my amps powered off (took the power lead off the battery) the front speakers don’t make a noise, so it’s definitely a noise the car is making that the amps are amplifying. Just can’t figure out what.
 
With the RCAs unplugged, touch a wire from the amp ground to the outer sleeve of the amp's RCAs.

This made a completely new noise, but didn’t solve the original noise.

I disconnected my amps as getting to the stock amp is a nightmare, the rear speakers still make the noise with my amps disconnected.

Just for my own peace of mind I’ll be trying a spare fresh set of RCA’s tomorrow, laid over the seats just to be sure. I’m pretty sure it’s not them but I will find out.
 
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James-TT

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