'Acoustic cameras'

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GusA
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Re: 'Acoustic cameras'

Post by GusA » Sun Jun 09, 2019 12:20 pm

The technical difficulties will be enormous and far more complex than speed. Differentiating due to weather, sound reflections, other traffic etc. Measuring the sound level of a single vehicle in test conditions is one thing, measuring your car as a motorcycle overtakes in windy conditions or any one of thousands of other scenarios is quite another. Noise checks during MOTs would be easier
P380 Convertible Ordered.....


simpleR
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Re: 'Acoustic cameras'

Post by simpleR » Sun Jun 09, 2019 4:34 pm

My V5C and the space where decibels should be is blank, which interested me so whilst sitting in the garden enjoying a G&T this afternoon and waiting for the Cottage Pie to cook and F1 to start I've had a look and found this.

According to the UK Government Vehicle Certification Agency

The external noise emitted by passenger cars has been controlled since 1929 when the Motor Cars (Excessive Noise) regulations were introduced. New cars are now required to meet Europe-wide noise limits. These have been progressively reduced from 82 decibels (dB (A)) in 1978 to the current limit of 74 dB (A) established in 2016.

The level of noise for new models of cars is recorded at their type approval test. Note that off-road vehicles are allowed to be 1dB (A) louder and wheelchair accessible vehicles or armoured vehicles are allowed to be 2 dB (A) louder.
The noise levels quoted above are the maximum levels that are permitted for new vehicle types. Many vehicles produce lower levels of noise, and it is illegal to modify the exhaust system of a vehicle to make it noisier than the level recorded for that model at type approval.

A new EU regulation was introduced from July 2016, Regulation (EU) No 540/2014, phases in tighter noise limits over 10 years, together with a revised, more representative test procedure. By 2026 the limit for most new passenger cars will be 68 dB(A).




OK, so what did my 400 Sport achieve decibels wise at type approval? (As it is missing from the V5C). Well a quick query to the UK VCA returns "Noise Level dB(A) Moving" = "70".

JAGUAR F-TYPE 400 Sport, 18MY 3.0L V6 (400PS) Supercharged Coupé & Convertible Auto AWD, A8-AWD

pic.png



Naturally had a look at some other cars as a guideline. All Db(A) figures. As recorded from cars type approval system. Drive by Noise in DB(A)

Current UK Limit for New Cars = 74
Jaguar F-Type 2.0L P300 = 70
Jaguar F-Type 3.0L 400S = 70
Jaguar F-Type 5.0L 550R = 71

So I think we all know and agree that a v8 is louder than 2L etc. But this of course is drive by noise. A set test where a car drives past a sensor at 20 metres away at a certain speed. I had a look at some other cars such as Mini Cooper S which was 71 and Vauxhall Astra 1.4 which was 72!
Imagine this question in a pub quiz. Your sat 20 metres away and bog standard Astra drives past and then a v8 F-type. Which would be noisier? The government data used for type approval says it would be the Astra!



So why is this relevant to the original post?

It is illegal to modify the exhaust system of a vehicle to make it noisier than the level recorded for that model at type approval under the 1929 Motor Cars (Excessive Noise) regulations.

So lets say that some time in the future you get caught by a naughty noise camera. All you would have to do is plead not guilty by post, attach a copy of the Government Type Approval for your vehicle and send it back. The burden of proof would be for court to prove their case of which if they tested your car and presuming your exhaust is standard it should return the same number on the Type Approval and then you suggest that perhaps the camera was faulty or another noise interfered. Ultimately, unless you have attached a drain pipe as an exhaust to 1L Corsa you'll be fine.

In fact it sounds (excuse the pun) such a bad idea I would bet it is scrapped after the trial. A waste of tax payers money. What we really need is some of those old fashioned things you used to see...... the ones who used to stop bad drivers, the uninsured, the middle lane hoggers, etc. Traffic cars and police I think they used to be called.

** note, all figures recorded are for active exhaust off.
400 Sport AWD - MY18 - Black, pano roof and thats about it 8-)


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scm
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Re: 'Acoustic cameras'

Post by scm » Sun Jun 09, 2019 6:17 pm

simpleR wrote:
Sun Jun 09, 2019 4:34 pm
... a bog standard Astra drives past and then a v8 F-type. Which would be noisier? The government data used for type approval says it would be the Astra!
Whether the V8 would be noisier rather depends on if it's driven past at tickover in a high gear or at 5000 rpm. ;)

Excellent post, BTW, thanks!
MY18 F-Type V8 R AWD in Glacier White
Lots of leather and toys, and loads of noise!


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PhilB
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Re: 'Acoustic cameras'

Post by PhilB » Mon Jun 10, 2019 8:42 am

simpleR wrote:
Sun Jun 09, 2019 4:34 pm
Naturally had a look at some other cars as a guideline. All Db(A) figures. As recorded from cars type approval system. Drive by Noise in DB(A)

Current UK Limit for New Cars = 74
Jaguar F-Type 2.0L P300 = 70
Jaguar F-Type 3.0L 400S = 70
Jaguar F-Type 5.0L 550R = 71
Just checked mine -74db.
Not bad for a saloon.
You lot need to catch up.
:lol: :lol:


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scm
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Re: 'Acoustic cameras'

Post by scm » Mon Jun 10, 2019 8:56 am

PhilB wrote:
Mon Jun 10, 2019 8:42 am
Just checked mine -74db.
Not bad for a saloon.
You lot need to catch up.
:lol: :lol:
Nah, we're just further away 'cos we're quicker! ;)
MY18 F-Type V8 R AWD in Glacier White
Lots of leather and toys, and loads of noise!


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PhilB
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Re: 'Acoustic cameras'

Post by PhilB » Mon Jun 10, 2019 8:58 am

scm wrote:
Mon Jun 10, 2019 8:56 am
Nah, we're just further away 'cos we're quicker! ;)
Only the V8!
:D
In all seriousness though, I can't believe some of these figures.
I'd like to know what this drive by speed test is.
What speed and which gear.
I had a V8 F-Type go past me a while back at full chat and I could still hear it half a mile past me !
:lol:


simpleR
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Re: 'Acoustic cameras'

Post by simpleR » Mon Jun 10, 2019 12:33 pm

Consulted the good folks over at Loughborough University and their Department of Aeronautical and Automotive Engineering. Quote:

Background
Vehicle pass-by noise limits exist since the 1970s and have been gradually reduced over the last decades. The reductions are supposed to account for higher traffic densities, urbanisation and well-being of the population. For example, the noise emission of a vehicle with a pass-by noise level of 82 dB(A) corresponds to the noise emission of six cars at 74 dB(A) nowadays, i.e. a reduction of 84%. Every recently developed vehicle prior to market launch has to comply with ISO 362, which has to be ensured by the vehicle manufacturer and suppliers during the development process.

The Test
Vehicle pass-by noise tests are conducted according to the international standard ISO 3622 from 1998, which intention is to reflect the noise emission of a vehicle in an urban traffic environment. Incase of a passenger car, the vehicle is driven on a straight line at a constant speed of 50kph approaching a 20m acceleration area. When the front of the vehicle reaches the acceleration area, the accelerator is fully floored until the rear of the vehicle leaves the area. Two microphones located midway in the acceleration area and 7.5m away from the centre line measure the A-weighted passby noise level. For a vehicle with manual transmission, the 2nd and 3rd gear are usually applied. The test is repeated four times for each gear. If the recordings are within 2 dB(A), they are averaged for each side and each gear. The average of the highest noise levels of each gear determines the pass-by noise level. To ensure equally equipped test facilities, the surface of the test site consists of Proceedings of the Institute of Acoustics Vol. 33. Pt.2 2011 which is a special tarmac according to ISO 108443.

How is that for an official answer folks?
400 Sport AWD - MY18 - Black, pano roof and thats about it 8-)


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scm
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Re: 'Acoustic cameras'

Post by scm » Mon Jun 10, 2019 3:31 pm

Ah, that explains it - the V8 wouldn't stay in the acceleration area long enough to register a reading! :D
And again, thanks for a brilliant post.
MY18 F-Type V8 R AWD in Glacier White
Lots of leather and toys, and loads of noise!


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steviegtr
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Re: 'Acoustic cameras'

Post by steviegtr » Mon Jun 10, 2019 11:35 pm

Its all boll-cks So I have a v8R that bangs so loud the cats in our village crap themselves when they see me coming. I have a Ducati multistrada with a full termi system that is just as loud. I am now in court with a solicitor saying these machines were bought from a main dealer with these exhausts fitted. Judge farts louder than a ferry foghorn & says next case please.
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basher
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Re: 'Acoustic cameras'

Post by basher » Tue Jun 11, 2019 8:06 am

steviegtr wrote:
Mon Jun 10, 2019 11:35 pm
Its all boll-cks So I have a v8R that bangs so loud the cats in our village crap themselves when they see me coming. I have a Ducati multistrada with a full termi system that is just as loud. I am now in court with a solicitor saying these machines were bought from a main dealer with these exhausts fitted. Judge farts louder than a ferry foghorn & says next case please.
:lol: :lol: :lol:
F-Type 400 Sport AWD Coupe, Rhodium Silver, panoramic roof, lots of other goodies... and pops 'n' bangs.
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