Static noise tests...
Discussion
Look at Motorsports Events website and see when they have a track day at Keevil, Hullavington or anywhere you can get to. Or find out when Castle Coombe has a day running and nip over there. The scrutineers will usually oblige if you smile sweetly and ask politely. At castle coombe you can buy an add-on dongle from the shop (can't recall the company name right now)if you fail!
You could always get yourself a sound meter of your own - fairly cheap for a decent one (try Maplins, or somewhere like that). You can then try different setups etc at home. (you'll need someone else to hold the sound meter at the correct position at the rear of the car, or set-up some kind of stand to hold it there, of course).
Edited by OrangeBob55 on Monday 19th November 16:40
TRPLBLK said:
The problem with that is that, as weather conditions change, the db level can change too. I've been told by the testers at Goodwood that you can pass one day and fail the next, or even pass in the morning and fail in the afternoon.
True. Even having a cold-ish engine/silencer can make the difference. But the most variable bit of the whole thing is the bloke holding the meter in my experience. MSA said:
The following is an extract from the MSA competitors’ yearbook:
“12.17.8. Sound Test Requirements. Measurements will be made at 0.5m from the end of the exhaust pipe with the microphone at an angle of 45° with the exhaust outlet and at a height of 0.5 to 1.0m above the ground. Where more than one exhaust outlet is present, the test will be repeated for each exhaust and the highest reading will be used. In circumstances where the exhaust outlet is not immediately accessible, the test may be conducted at 2.0m from the centre line of the vehicle at 90° to the centre line of the vehicle, with the microphone 1.2m above the ground. Measurements should be made outdoors with no large reflecting objects (e.g. walls etc.) within 3.0m (in the 0.5m test) or within 10.0m (in the 2.0m test). Background sound levels should be at least 10dB(A) below the measured level.
Where possible measurements should be taken as close as possible to the vehicle, at the defined distances, to avoid background noise. Cars of periods A to D falling within Sections C and D should run engines at two thirds maximum RPM. The 2.0m test can be made from either side of the car. The highest reading registered being the one needing to comply with the maximum noise requirements.”
“12.17.8. Sound Test Requirements. Measurements will be made at 0.5m from the end of the exhaust pipe with the microphone at an angle of 45° with the exhaust outlet and at a height of 0.5 to 1.0m above the ground. Where more than one exhaust outlet is present, the test will be repeated for each exhaust and the highest reading will be used. In circumstances where the exhaust outlet is not immediately accessible, the test may be conducted at 2.0m from the centre line of the vehicle at 90° to the centre line of the vehicle, with the microphone 1.2m above the ground. Measurements should be made outdoors with no large reflecting objects (e.g. walls etc.) within 3.0m (in the 0.5m test) or within 10.0m (in the 2.0m test). Background sound levels should be at least 10dB(A) below the measured level.
Where possible measurements should be taken as close as possible to the vehicle, at the defined distances, to avoid background noise. Cars of periods A to D falling within Sections C and D should run engines at two thirds maximum RPM. The 2.0m test can be made from either side of the car. The highest reading registered being the one needing to comply with the maximum noise requirements.”
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