Noise test meters

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Discussion

heebeegeetee

Original Poster:

28,591 posts

247 months

Tuesday 5th May 2015
quotequote all
Hi all,

Took a hill-climb car to Shelsley at the weekend just to be scrutineered and noise tested, car not been run since an engine change and other work.

Failed the noise test miserably at 115db. I've since downloaded an app on my phone which measures the noise at just 60 odd db, which is nonsense of course.

Can anyone recommend an affordable noise tester which may be good enough to give a reasonably accurate reading? I see there are plenty on ebay http://www.ebay.co.uk/sch/i.html?_from=R40&_tr...
are any of them any good, or they likely to be as useful as the app?

It would be useful to have an indication, save me having to take my car to venues to be measured so that I can be sure of entering an event and not failing noise on the day.

Many thanks.


Drumroll

3,738 posts

119 months

Tuesday 5th May 2015
quotequote all
Noise meters can be picked up very cheaply, but getting one that is calibrated and keeping it calibrated is the hard part. In the end it doesn't matter what your meter says, if the Environmental scrutineer says it is too noisy it is too noisy. I know it doesn't help you at the moment, just pointing out the obvious really.

Jayyylo

985 posts

146 months

Tuesday 5th May 2015
quotequote all
I'd wager you've got your app on the wrong settings. Obviously it's not going to be as accurate but it should be within about 3 dB. Any meter you buy off ebay for £20 will have about the same accuracy as an iPhone app (at best) to a properly calibrated class 1 meter.

EDIT: After re-reading I realised my last sentence wasn't too clear on what I meant. Fixed now.

Edited by Jayyylo on Tuesday 5th May 15:22


Edited by Jayyylo on Tuesday 5th May 15:22

vjay48

191 posts

158 months

Tuesday 5th May 2015
quotequote all
I bought a meter from ebay for about £18,shows the same reading as the one used at a 2 track day tests. I don't think the warning from the previous poster is accurate. The two test were at Bedford and Snetterton both noise sensitive venues.

mozzerS

121 posts

204 months

Tuesday 5th May 2015
quotequote all
We went through a similar thing after measuring 112dB at our first sprint.
I bought a digital sound level meter from Maplin for about £40, not the cheaper mini one, as you need to make sure whatever you get measures in dB(A) - as opposed to dB(C).
I also tried an app called SPL Meter that gave a good indication compared to the meter. Remember to set the 'response' option to 'slow' and select a suitable range.
Ultimately it's the meters at the events that decide but if like us, you're looking for the difference when you try changing something these should help. We needed a new silencer and bigger silenced decat but we had to get below 105 for track days and test days.
Cheers

heebeegeetee

Original Poster:

28,591 posts

247 months

Tuesday 5th May 2015
quotequote all
Drumroll said:
Noise meters can be picked up very cheaply, but getting one that is calibrated and keeping it calibrated is the hard part. In the end it doesn't matter what your meter says, if the Environmental scrutineer says it is too noisy it is too noisy. I know it doesn't help you at the moment, just pointing out the obvious really.
Thanks, and that's right about on he day. 115 db is really disappointing though and tbh I'd like to get below the 105 to save faffing about on the day. I can save that for later after we've got used to running the car etc.


Jayyylo said:
I'd wager you've got your app on the wrong settings. Obviously it's not going to be as accurate but it should be within about 3 dB. Any meter you buy off ebay will have about the same accuracy (at best) to a properly calibrated class 1 meter.
I don't think there's any settings to alter, but I'll try another app before buying anything from eBay. Thanks anyway.

GC8

19,910 posts

189 months

Wednesday 13th May 2015
quotequote all
Even if you are within 3dB (using the correct weighting) then the difference in readings could equate to a doubling of the sound pressure!

Jayyylo

985 posts

146 months

Wednesday 13th May 2015
quotequote all
GC8 said:
Even if you are within 3dB (using the correct weighting) then the difference in readings could equate to a doubling of the sound pressure!
Simplified:
3dB = doubling of energy
10dB = doubling of sound pressure level (twice as loud)

heebeegeetee

Original Poster:

28,591 posts

247 months

Wednesday 13th May 2015
quotequote all
I downloaded one free app called Noise Meter, supplied or 'powered' by something called Unity, and it was useless. I tried another one called Decibel 10th, which gave a much more realistic reading, (albeit lower than the scrutineer), and since paid 79p to get rid of the adverts. smile

We discovered the wastegate was stuck partially open on the noise test, which would lose the dampening effect of the turbo. We've remedied that and hopefully will get it noise tested again this weekend. Only problem is, according to Decibel 10th closing the wastegate made no difference.

We'll see, and I'll report back. Cheers.

GC8

19,910 posts

189 months

Wednesday 13th May 2015
quotequote all
Jayyylo said:
GC8 said:
Even if you are within 3dB (using the correct weighting) then the difference in readings could equate to a doubling of the sound pressure!
Simplified:
3dB = doubling of energy
10dB = doubling of sound pressure level (twice as loud)
Id have articulated that as 3dB = doubling of sound pressure and 10dB = doubling of perceived noise, but I think that we are both saying the same thing.

Jayyylo

985 posts

146 months

Wednesday 13th May 2015
quotequote all
GC8 said:
Jayyylo said:
GC8 said:
Even if you are within 3dB (using the correct weighting) then the difference in readings could equate to a doubling of the sound pressure!
Simplified:
3dB = doubling of energy
10dB = doubling of sound pressure level (twice as loud)
Id have articulated that as 3dB = doubling of sound pressure and 10dB = doubling of perceived noise, but I think that we are both saying the same thing.
I was just clarifying as it's a common mistake people make when they don't understand a logarithmic scale. Clearly you do and everything is fine smile

BertBert

18,953 posts

210 months

Wednesday 13th May 2015
quotequote all
I've got what I'd call a standard Maplin meter. When I have used it in the past it has given me very similoar readings to the circuit noise man (or men).
Bert

heebeegeetee

Original Poster:

28,591 posts

247 months

Wednesday 13th May 2015
quotequote all
BertBert said:
I've got what I'd call a standard Maplin meter. When I have used it in the past it has given me very similoar readings to the circuit noise man (or men).
Bert
Ta.