measure sound power and sound intensity with NI USB-9233

[Ronny_C]

Dear,

I'm new to Labview and I have a question. A few weeks ago, we have bought a CompactDAQ system with among other things a USB-9233 card.

Now I have found out it's also possible to do sound measurements with this card.

I would like to do sound intensity measurements and sound power calculations. Is it possible?

I have LV 7.0 and the Sound and Vibration Toolset for LV. Do I need additional hardware and/or software?

We currently have B&K microphones and a B&K sound intensity probe. Can I use them with the 9233 card?

Or do we need to buy new equipment?

Thanks in advance,

Ronny C

[Kurt_Veggeberg]

The USB-9233 only works with pre-polarized microphones.   This means that the ICP (IEPE or Deltatron as B&K calls it) is always enabled.   IThe sound intensity probe you have probably requires a 200V power supply.    We have a new module coming out soon (January 2008) called the NI 9234 that offers options to enable/disable the ICP as well as AC/DC coupling and 51.2 kS/s sampling rate.   

With this you could use your sound intensity probe with this module if you had a precision power supply.   It will also work with our other dynamic signal acquisition producuts like the NI 446X, NI 4472, and NI 449X that allow you to turn-off ICP.   You can use the 9233 with a GRAS sound intensity probe that has ICP type microphones.   

In addition, one of the GRAS designers gave a presentation at NI Week on making Sound Intensity measurements with LabVIEW that I can send to you.   They are going to offer the code to interested users and we will post it on our web site.    In addition they plan to implement a multi channel version for vector intensity with our higher channel count products.  

You would need to have the Sound and Vibration toolkit or Measurement Suite with LabVIEW 8.X for optimal results.   The latest version of the Sound and Vibration toolkit just released in December with additional features including the Sound and Vibration Assistant, human vibration filters, and more Express VIs.  

Kurt Veggeberg

Business Development Manager, Sound and Vibration

kurt.veggeberg@ni.com

[Ronny_C]

Thank you Kurt for the information!

So, if I understand it correctly I will need a 200V power supply if I want to use my probe or the one of GRAS,

or I can choose to buy the 9234.

Could you send me the GRAS presentation ?

Ronny C,

rcmn@picanol.be

[Sinha]

Hi Kurt

I am using 9233 for vibration measurrement. I have developed on 4-channel FFT anlyser for machiney vibrtaion measurement. I would be interested to received the resources you offered to share. Please send me them to sinha_sk@indiatimes.com . I would be delighted to see some tacho input available to USB 9233 with which I can develop the Order Analysis system fully portable. Please let me NI is thinking in this direction.

Sunil Sinha

[SwedeBill]

Would there be a problem in connecting the GRAS microphone power supply output directly to the input of the NI-9233 module even though the IEPE current is always on?

[Wilfried_71]

I already realized sound measurements with the 9233 module, using B&K microphones and charge amplifiers (the charge amplifier ouputs X mV/Pa).

[Kurt_Veggeberg]

The USB-9234 and NI 9234 which is releasing this quarter allow you to turn off ICP and support AC/DC coupling. For an analog tach input, you would just turn off the ICP for one channel.    Another option is to use in-line charge amplifiers with the 9233 which will replace the power amplifier.   These are available from several suppliers.  

In addition, the new Sound and Vibration Measurement Suite now supports our Order Analysis routines in both Express VIs and in the Sound and Vibration Assistant. The new examples are very easy to use and the project environment of the Assistant is even easier.

[Kurt_Veggeberg]

New sound intensity example posted on our web site

http://zone.ni.com/devzone/cda/epd/p/id/6353?submitted=yes

This example demonstrates how to make a sound intensity measurement using LabVIEW. It requires the Sound and Vibration Toolset to be installed.

This example uses LabVIEW and the Sound and Vibration Toolset to implement a sound intensity measurement.  There are several ways to compute sound intensity and this example uses the time domain outputs of octave filter banks so the results can be present in an octave spectrum.

[MSingh]

Kurt,

Thanks for the example. Is there a LabVIEW example that can compute sound intensity in narrow band? Please direct me to its location on the web, if available.

Thanks for your help.

M Singh

[AlanArmstead]

The example that Kurt linked to above has controls on the front panel that allow the user to select the frequency range.  So, you can make that example operate on a narrow band if you desire.

-alan