Mechanical Noise

In searching for information and ways to reduce noise and vibration from mechanical and process equipment I came across the following site.

http://www.soundintensity.com

Is anyone else here familiar with the use of sound intensity measurements and how the may benefit a manufacturing / process operation?

I have found little other information about this application.

Dave

 

[080175]

hi Dave ,

Can you tell me more about your system,

i am working on active noise control

Bye

 

[peterschmidtpe]

Dave:

Intensity measurements are more usefull in a laboratory setting. I am a former consultant on industrial noise, and I would suggest either engaging someone in the field or doing some study yourself.

Acoustical Consultants can be found on these web sites:

Institute of Noise Control Engineers

http://users.aol.com/inceusa/ince.html

National Council of Acoustical Consultants

http://www.ncac.com

Personal Recommendation:
amarash@cdai.com

Beware of "free" engineering offered by sales reps for acoustical treatment companies. Their fiduciary responsibility is to their respective sales organizations, not to you. They may recommend what their quota needs, not what is best for your situation.

Most industrial applications require a mix of remedial actions, the most common being addition of absorptive acoustical treatments to the work space and some type of enclosure for the problem equipment.

Suggested reading:
Noise and Vibration Control, Beranek
Shock and Vibration Handbook, Harris
Sound Analysis and Noise Control, Foreman
Sound, Noise and Vibration Control, Yerges

I hope this information is helpful.

PLS

 

[ANTOINE]

Dave,

What is exactly the problem you are facing ?
Sound intensity is helpful in noisy environment to quantify and localize sources.
You can send info to : thomas.antoine@metravib.fr

http://www.metravib.fr

 

[Hatch]

One of the key applications I know of in an industrial setting is product testing. Products are routinely and/or automatically tested to ensure that they meet noise emission standards.

You could also measure a component in an assembly for a maximum level as a quality test. However as suggested by the other posts, sound intensity requires considerable knowledge to be applied correctly.

 

[GregLocock]

Sound intensity measures the FLOW of sound power through a given region. If you measure the intensity correctly around a given system it will give you the total sound power radiated by the system, hence it's contribution to the noise in a given environment. SI can also be used to identify which parts of the system are radiating a particular frequency component, which may help if you are trying to quieten the system down.

This sounds like the answer to a maiden's prayer (or indeed, a naive acoustics engineer's prayer!). As others have intimated, it is much more complex than that and is rather tricky to use in many practical situations. I work in the automotive field so my experience is with engines. If we need to identify which part of an engine is radiating a particular frequency we use a SINGLE microphone, an impact hammer, and accelerometer, and some common sense.

Some engine manufacturers use estimates of panel surface velocity to generate overall sound power levels, and individual contributions, but these are always cross-checked back to the standard method of determining the overall sound power level, which uses 4-7 microphones in an array around the engine, and then back calculate the sound power level from the sound pressure levels. The SAE has a standard describing this.

Intensity has its uses, but it is not usually the primary approach.
Cheers

Greg Locock

 

Greetings,

Thanks for the quick feedback and information (and reading resources!) It seems to be a highly specialised and limited application, as does "active noise control" from what I have seen, albeit I only have a "laymans" opinion.

No worries here, I just wanted to make sure I wasn't missing out on something I should know more about. No such thing as a "quick fix!"

Dave

 

[motorman]

this is where i send my customers first when they complain about noisy equipment and what can be done about it:

http://personal.cityu.edu.hk/~bsapplec/sound2.htm