Using White Noise for noise abatement

[Doug Siddons]

A client has asked me about reducing noise from his outside smoking area using a device generating white noise like this http://www.acousticalsurfaces.com/white_noise/white_noise.htm

 

I have no experience of this, they are apparently used in open plan offices for privacy ect. My gut feeling is that the white noise would have to be loud enough to drown the conversations and therefor create a bigger problem than the conversations. Does anyone have some experience of this?

[Brian]

Err, if the neighbours are complaining then the white noise will just add to the chatter and make the situation worse.

[paulears]

The product is designed to prevent the sound of people talking being understood at a distance, not to reduce level. It's a masking product not a level reducing one.

[S&L]

this is my day job again...

the EHO is interested in the difference between the background level without the nuisance and the level with the nuisance - whatever that level is comprised of. the standard approach is to take a noise level when it's quiet - ideally at the complaint position (maybe outside restaurant/bar hours) then take the level again when the nuisance is in place. if the first level is exceeded then the onus is on the noise maker (restaurant/bar etc) to reduce the level to the background noise.

this reduction can be achieved wither by eliminating the cause or attenuating the cause. the maths of acoustics work against you if you produce another noise i.e. noise source 1 plus noise source 2 equals bigger noise source 1+2.

solutions I have employed in the past - acoustic screens, ventilation attenuators, better glazing etc. with open air conversation, assuming it increases the sound level at complaint origin (and it's always worth checking and quantifying the problem) then you are looking at acoustic screening (expensive) or relocating the conversation.

[TallMike]

We are doing this for a festival in August. The theory is that you are not distracted in any way by white noise, your ears 'adjust to it', much the same as traffic noise if you're near a motorway. whereas chatter, kids etc distracts you and you can pinpoint where it's coming from and the unexpected noises annoy you. So theoretically the slightly increased SPL is not perceived as such by your brain, or rather not noticed.

[Doug Siddons]

Thank you for your replies. They are as I expected but had to check, The problem is a town centre pub next to a Nursing home and the smoking ban.

 

( I can't get the idea out of my head, that the current trend to play white noise to help babies sleep had something to do with this !)

[Simon Lewis]

Doug,

 

In one sense, the idea is not without merit. Often, background noise is taken as the baseline and the nuisance must not exceed background levels. When there's plenty of traffic etc., background levels can be pretty high, so we "get away" with our noise making activity.

 

Putting white noise out into the environment wouldn't be seen as "normal background" though ;-)

 

Regarding babies, part of the thinking is if you keep a fairly constant level of background noise, some small changes (talking, walking up stairs etc.) shouldn't disturb them. Wise mums have been running their washing machines to do this for years!

 

 

Simon