What is the best way to save sound signal data?

[scmancl21]

I have the NI USB-9233 DSA interface with labVIEW 8.5 and the Sound and Vibration Toolkit Version 5.0.  I am aquiring a sound signal from a microphone at a sample rate of 50k.  My goal is to save this data to a file in such a way that I can reload it to run comparitive Power Spectrum FFT and octave band plots. The duration of the recording time could be anywhere from 5 sec to 30 sec. What is the best format to save the data in, ASCII, WAV, UF558? 

Scott

[Jordan_D]

Hi Scott,

There certainly are a number of ways to store your information. Since the files you are writing are not especially large (2-12 Mb), you don't have to be too concerned with file size. I recommend using the following two example files used to write and read .WAV files.

SVXMPL_WAV Recorder (DAQmx).vi
SVXMPL_WAV Power Spectrum.vi

These examples can be found in the LabVIEW's Example Finder under

NI Example Finder » Toolkits and Modules » Sound and Vibration » File Input and Output » ...

[scmancl21]

I've looked at the wav recorder and my concern starts within the sound write waveform vi.  I know the vi is scaling the signal, but I can't follow exactly what's it's doing.  When I've tried to step into the vi, I've been only able to step over it.  I've attached a word document with a picture that points to where I'm getting lost.  Basically, I don't mind if the signal is scaled/amplified, but I do need to know what that gain is and that it need is constant test to test so that when I start comparing tests, I know how to scale it to decibel units.

Thanks,

Scott

[Jordan_D]

Hi Scott,

You are correct in thinking that the AI Max/Min are taken from the front panel of the Wave Recorder VI. These values are passed into the task inside the svx_DAQmx Get Info VI. There isn't any scaling performed in this VI. Keep me posted if you have more questions.

[Oli Oli Oxin Free]

I don't have it installed apparently so I need the sound and vibration toolkit. Does that cost money and how do I install it.

Thanks

[Jason_D]

Hi Oli Oli Oxin Free,

Here is a link to the Sound & Vibration Product page.  It is not free.  On this page there is a link to evaluating the software which will guide you through the installation process.

If you would like I can get you in touch with a sales representative about purchasing this. 

Please let me know if you have further questions!

[dsb@NI]

You can evaluate the Sound and Vibration Measurement Suite 7.0 for 30 days before making a purchase. During the evaluation period, the evaluation license allows full use of the product. We would appreciate your feedback and, hopefully, your business .

[Balanceman]

I have read somewhere that WAF does not maintain the gain of the signal. I am not sure about this, but maybe you should be careful there.....

Seems that TDMS is a preferred file format for dynamic signals. I have only very recently started to use it with LV 8.6, but is seem to be quite useful.

Cheers

Gerd