Greg,
I worked with Nelson and Elliott on one of their first ANC system. Most of the systems I have used since then have been 'home-brewed' (if you can call systems like a 196 actuator by 64 sensor control system 'home-brewed').
I'm impressed that you could cancel exhaust noise using the...
I regret that I must beg to differ from Greg, or at least qualify his assertion. Yes, it might be possible to make a home-brew ANC system work if you have a fixed frequency point source at one location. However, unless you are very lucky (or very clever), you will only get reduction at one...
Greg is right but I doubt you will be able to home-brew a system. There are many technical difficulties to be overcome to make this work (which is why there are no products). For more information about active noise control see...
Any good noise control textbook should give you the background. Try Kinsler and Frey or Beranek. This site explains it quite well.
http://www.norsonic.com/web_pages/frequency_analysis.html
These are the relevant standards
Designation: ANSI S12.1-1983 (R1996)
Title...
You need a calibrated sound level meter and a map. For someone with experience, I could give you the name of a noise control engineering in your area.
Masking the noise of a wind turbine seems to me a difficult thing to do. I know of a recent paper in the Journal of Sound and Vibration on the...
I don't know anyone that has experience of the non-linear stress analysis. You might contact your ANSYS rep for a recommendation.
I see that you have posted on the ANSYS board here too. You might get some response there. If you are really stuck, I might be able to help.
Broad Arrow...
If you are a registered ANSYS customer you can access the manuals online. See http://www.ansys.com/education/resources.htm.
or try
http://www1.ansys.com/customer/content/documentation/60/index.html
Your problem sounds like something an ANSYS expert could put together in a few hours. Do you...
1. The impedance is different in your two cases. Assume a left and right going plane wave in the tube and solve for the boundary conditions at the two ends.
2. I am a little confused about the way you phrased your question. The impedance (which impedance by the way, mechanical, acoustic or...
A waterproof loudspeaker won't work, although a moving coil transducer (say a Ling shaker) driving a metal piston might do it. You only need around 20 um displacement to produce a 0.1 GPa plane wave at 500 Hz. A typical sonar transducer won't work as it can't move enough.
Broad Arrow Acoustics...
You may have some confusion between two characteristics of microphones.
1. All microphones have a sound level below which they cannot measure due to the electrical noise that is inherent in their components.
2. Some microphones are designed to be used in an acoustically noisy environment (e.g...
I have used ANSYS for acoustic transducer design. A very good general forum for ANSYS technical questions is the xansys group on Yahoo.
http://groups.yahoo.com/group/xansys/
What is your specific question?
