Noise Meter

[Graham King]

Hi, can anyone recommend a good value (i.e. cheap) noise level meter, I am considering doing the MSV track day at Brands on Royal Wedding day but the noise level is 98db.

 

I have no idea what mine reads but am a bit concerned that it may be more than this, I have looked at iPhone apps but it appears the iPhone mic cuts out at 100db so is probably of little use.

 

Or can anyone recommend somewhere I can get it tested?

 

Thanks.

 

Graham.

[Jerry Auton]

CBC do one, but can't vouch for it's accuracy etc here

[2slo]

Phone the circuit admin office and ask if they can test your car prior to booking. Not sure about Brands, but other circuits (e.g. Croft) do this for free at a prearranged time. That way you would be certain.

[Graham King]

Jerry, thanks for the link.

 

2slo, I thought about that, the problem for me is getting down there beforehand, I don't get back in time for an evening and am self employed so taking a day off to do it gets costly.

 

Does anyone have a view on how restrictive 98db is likely to be. I have an R400 spec K-Series with airbox and a Powerspeed 4-2-1 wth 6" can.

 

Graham.

[bluenose]

Emm noise testing, the most in-exact science when done by Motor Racing circuits. You could buy a noise meter but there really is no point as it really depends on how they test you. They normally have a stick attached to the meter that they hold at approximately 45 degrees to the exhaust outlet for static testing and then you give them a maximum revs figure that they then use to calculate a figure that you need to rev it to, I think 2/3 or 3/4 max? I have been tested at different circuit with very different figures each time, but MSV never seem that strict at Brands from what I remember.

 

You say you have an airbox and a Powerspeed silencer so I would have thought you would be OK, but there is no guarantee. Someone on here must have a similar spec car that has done a track day at Brands recently I would have thought?

 

Nick

[Jonathan Kay]

Review of iOS apps, but run on an iPad rather than an iPhone for some reason. SPlnFFT came out best.

Jonathan

[Grubbster]

Maplin do a few, I bought one from them years ago and it seems to compare reasonably well to the measurements I get at circuits.  With your set up you ought to be just OK, I run a slightly higher powered K with no airbox (but an under the bonnet foam filter) and I used to have a 6" powerspeed 4-2-1 set up - as long as it was packed OK I used to measure 96 - 98 at 4500 revs (which is what was asked for most of the time). Some circuits asked for 3/4 of max revs so I started offering a tad over 5000 (should have been 6000 plus really!) so I started to get a bit too close to the limits and have since fitted a Raceco and that made a huge difference.

[Jonathan Kay]

Have you got an iOS device to compare that app with your dedicated meter, and possibly even both of them back-to-back the next time you're tested at a track?

Thanks

Jonathan

[Julian H]

I have used this one several times over the years [borrowed from work for various tasks] and it always works well.

[LesG]

I use the 'mini' version in that link from Julian, and is pretty accurate and compares to any of my sprint events. For £20 it is peace of mind

[Tigger]

..... Or hire one from Book-a-track, I've done this a couple of times

http://www.bookatrack.com/shop  Scroll down a bit

Tim

[Jonathan Kay]

Any more recent experiences, or reputable reviews?

Thanks

Jonathan

[Dobson_justin]

I have a 235bhp k series with power speed exhaust, and it has been tested at a few track days and Club Speed events and is around 89 or 90db. 

I was worried for my first event, but have never had a problem. 

[Jonathan Kay]

That review of apps upthread that came up with SPLnFFT was from 2017. 

Any experiences or later reviews?

Thanks

Jonathan

[smartizan]

Just to urge some caution with Apps for measuring noise.  I spent my career working in acoustics (although not in the automotive industry), and as part of that, ran some tests on various apps to see if they were any good.  The bottom line was:

As Jonathan says, they are better for relative measurements rather than absolute. 

They are more consistent on Iphones than other devices because the microphones have broadly the same sensitivity as they come from the same supplier.

There is a big difference between dB and dB(A) – not all measure the dB(A) level (the level expressed in dB(A) will always be lower).  Also, some tests require averaging over time (to measure the LAeq) which is an added complexity some apps cant deal with.

They are very sensitive to wind noise so not ideal for measuring out of doors

The microphones in phones are directional so how you point the phone is important.  The phone case can also make a difference.  A professional sound level meter will have an omni-directional microphone so is much less affected by direction (important if you are doing a drive-by test).

Its very difficult to calibrate a phone – protocols for noise measurements almost always require the noise meter to be calibrated before and after use with a standard sound source that fits over the microphone.

The test we ran in a semi-controlled environment gave a range of +/- 20dB(A) from a mix of different phones and software packages.  That’s a big variation.

[Jonathan Kay]

It's always great to have experts.

Thanks

Jonathan

[Jonathan Kay]

On 26/01/2016 at 17:51, Jonathan Kay said:

Review of iOS apps, but run on an iPad rather than an iPhone for some reason. SPlnFFT came out best.

Same review from 2014 but with updates from 2016 and 2018.

The testers have produced their own app for industrial exposure testing: NIOSH Sound Level Meter App.

...

NB: iOS only because they found the variability of Android devices to be too high.

Jonathan

 

[Jonathan Kay]

And, because of that important discussion elsewhere about tinnitus: a group test of apps for frequency analysis, but of course much of it is about audio production rather than limits at tracks or protection of hearing.

Jonathan

[Graham Hutton]

What a brilliant little app! Will try it next time I'm out in the Caterham.

Thanks