Strange noise when driving

Faults and Technical chat for the CUPRA Born
Ponk
Posts: 108
Joined: Wed May 03, 2023 6:25 pm
Location: AG, Switzerland

Post by Ponk »

Hey all

Just wondering if anyone had a chance to listen to my sound file (just press play on the green bar on post above, and listen around the 2:00 to 2:20 time line and see if you recognise the noise. Much appreciated, thanks.
Cupra Born, 77Kw, Silver, 20" Firestorm, Advance Pack, Beats, Heat Pump, Swiss Model.

Thelor
Posts: 14
Joined: Thu Jan 12, 2023 7:00 pm

Post by Thelor »

What wheel size are you running? The first Born I tried had 19" with Bridgestone on them. They were incredibly noisy with a strange hum at highwayspeeds. Current Born came with and is currently running on 20" Eco contact 6. Not the most silent tires I have had but no humming.
Ponk
Posts: 108
Joined: Wed May 03, 2023 6:25 pm
Location: AG, Switzerland

Post by Ponk »

20" wheel size, tyres are Michelin Pilot Sport EV, 235-40.
Cupra Born, 77Kw, Silver, 20" Firestorm, Advance Pack, Beats, Heat Pump, Swiss Model.
alanjs
Posts: 151
Joined: Mon Jun 27, 2022 3:14 pm

Post by alanjs »

Ponk wrote: Sat May 13, 2023 6:28 pm Hey all

Please try the link below and see if my file can be heard. The noise is always there, but is easiest to hear from about 1min onwards, and probably loudest at about 1:50 to 2:15. 2:35 is slower speed and you can hear it also as the wind and road noise are much less.

I think I can hear some minor noise, but I wouldn't find it intrusive, but ETTO.
Have you tried varying the air-con/ventilation fan and outlets? On my previous Golf I had a much louder whistle than yours, but I could get rid of it by adjusting the vents.
Born V3, Aurora Blue, Tech (M) pack, Firestorm wheels, Pano roof
Ordered 21 June, 2022, delivered 17 Jan 2023
Elea4
Posts: 198
Joined: Fri Jun 10, 2022 5:19 pm

Post by Elea4 »

Ponk wrote: Mon May 22, 2023 7:30 pm Hey all

Just wondering if anyone had a chance to listen to my sound file (just press play on the green bar on post above, and listen around the 2:00 to 2:20 time line and see if you recognise the noise. Much appreciated, thanks.
When you're driving the fastest the frequency of the sound is 210Hz and at the end when it seems like you're driving slower it's 200Hz.

The tires should have a diameter of 693mm, meaning that at 100km/h they're rotating at 765rpm and at 50km/h 382rpm.

So it's doubtful that it's related to the drive train as you would see a larger change in pitch.

My guess is that it's caused by wind resonance on some part of the body or through the ventilation system as the volume varies in an unpredictable way.
Ponk
Posts: 108
Joined: Wed May 03, 2023 6:25 pm
Location: AG, Switzerland

Post by Ponk »

Hi

Thanks for the technical details, I tried to find some free software to analyze the sounds and maybe single the sound out but had no luck.

The noise comes from the front of the car, it is not tyre noise as I can hear that separately, I can hear the noise at 30mph already, and as you drive faster, the only thing that changes is that the volume gets a bit louder. In a tunnel it is louder. It's as if it's either the front axle, or even wind noise like someone suggested. I also notices of mental panels that make joins on the road on bridges, this amplifies the noise which makes me now think it is not wind related.

I am in two minds to contact the garage, maybe even arrange to put my winter wheels on to see what the difference is, or just wait until end October when I change them anyway.

Thanks again for your feedback, much appreciated.
Cupra Born, 77Kw, Silver, 20" Firestorm, Advance Pack, Beats, Heat Pump, Swiss Model.
Elea4
Posts: 198
Joined: Fri Jun 10, 2022 5:19 pm

Post by Elea4 »

I isolated a couple of frequencies, namely 200-210Hz and 972Hz - you can hear it better in the WAV file I attached:

210Hz-tone.jpg

972Hz-tone.jpg

born.zip
(4.75 MiB) Downloaded 88 times
Ponk
Posts: 108
Joined: Wed May 03, 2023 6:25 pm
Location: AG, Switzerland

Post by Ponk »

Thank you so much Elea for your time doing this for me. The WAV file sounds really good, and it's something I can use for when (I expect) the dealer says he hears nothing unusual!

I still think it's a mechanical sound, I can hear it even from about 25mph onwards, if the road surface is slightly rough, it's louder, so driving at 30mph on a slightly rough surface road, is louder than 50mph on a smooth road.

But anyway, I will decide what to do in the next weeks and if I find anything out I will be sure to post what happened.
Cupra Born, 77Kw, Silver, 20" Firestorm, Advance Pack, Beats, Heat Pump, Swiss Model.
Elea4
Posts: 198
Joined: Fri Jun 10, 2022 5:19 pm

Post by Elea4 »

If the frequency is constant despite different motor/driving speeds, the only way it could be mechanical is if it was some other pump/compressor whose speed wasn't varying during that recording.

Glad to help - audio production is my main profession.
Ponk
Posts: 108
Joined: Wed May 03, 2023 6:25 pm
Location: AG, Switzerland

Post by Ponk »

Exactly my thought's on the frequency too. Thanks again.
Cupra Born, 77Kw, Silver, 20" Firestorm, Advance Pack, Beats, Heat Pump, Swiss Model.
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