Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Noise measurement question

Noise measurement question

Noise measurement question


Need some professional advices.

I have a project requiring to measure noise in accordance to Indoor Air Quality (IAQ).
I have doubts about the method statement of how this noise measurement should be taken.
Is it acceptable to just take the noise in dBA?
At what level and which point the noise should be taken? Must the height be fixed or it can be random? (deem that the noise level does not vary too much at about 0.8m to 1.5m from floor level.)

Lets say my ambient condition without AHU equipment running measured noise level at 55 dBA. And with the AHU turned on, i measured 68dBA.
How can i determine the noise level of the AHU alone? (without the ambient noise)
Any calculation that can be performed to get the AHU noise level?

Can anyone recommend some instrument / device with model no. that can measure noise in different frequency.


RE: Noise measurement question

I think the answer to your first two questions will be in whatever spec you are using. If left to my own devices I'd use dBA to find the trouble spots and spectra to solve them. SLMs are often placed 1.2m above the ground. This discriminates against midgets but lets most people operate them.

As to your problem with dB arithmetic, AHU=10*log(10^6.8-10^5.5) which is pretty much going to be 68dBA

Random googling led me to this instrument, it seems pretty typical http://www.nti-audio.com/en/products/xl2-sound-lev...

Personally I would go for a decent multichannel A/D on a laptop with a decent mic, single channel stuff is fine for surveys but not for problem solving.


Greg Locock

New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


White Paper – Data Security and Know-How Protection
Our data is constantly exposed to the danger of being intercepted or stolen as it wends its way over global data networks. Data security measures and measures for protecting intellectual property should not, however, first be implemented when data is exchanged – companies must lay the foundation for these measures within their own organization. Download Now
White Paper – Collaboration in the PLM Context
The influence exerted by the Internet of Things (IoT) means that there is a steadily growing need for collaboration in industry. Partners from new industries and areas of application need to be integrated in cross-company business processes to ensure that the lifecycle of smart, connected products can be managed from end to end. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close