Manipulate sound going into a DAQ

[VeritasAequitas]

Hi i am working on a project and i selected one that uses a microphone and the sound input and sent to a DAQ card and in software I will look at the sound and make sure it is in an acceptable decible range. If the decibles are to high labview will decrease the amplitude and if its to low it will increase the amplitude. Then labview will output the sound to the computers sound card. I working on this project because a car accident made me deaf in one ear and i am working on ways to manipulate sound so that i can someday help myself be aware of things going on my right side. I just need some ideas on how i can do this.

[Rialter]

Hi ajh305;

Here is a link that you might find useful, in which some of Labview sound analysis tools are explained and I think you could be specially interested in the Power in Band tool, but some other of those blocks can also be useful, I'm still searching for more documentation to help you, so if you have any doubts or need more help just ask.

http://zone.ni.com/reference/en-XX/help/372416A-01/svtconcepts/time_averaging/ 

Francisco Arellano

[VeritasAequitas]

How exactly could I use these. I just started using LabView for a class at school and these examples are pretty much out of my league haha. What specific functions can be used to increase or decrease a sound wave?

[Corby_B]

Hello ajh305,

Thanks for your post! You mention that you have some limited LabVIEW experience so if you have some time I would recommend looking over this link. 

Learn 10 Functions in NI-DAQmx and Handle 80 Percent of Your Data Acquisition Applications

This link talks about how to use the DAQmx driver which is how you will get the data from your DAQ device. Just curious which device are you using and in what version of LabVIEW?

Fransisco gave a great link and that would be a fantastic way to do this. Here is another link that might help you. It takes the data from a DAQ board and outputs it directly to the sound card of your computer. All the controls are user selectable so to automate this will take some programming. 

NI-DAQmx: Acquiring Audio and Transferring It to a PC Sound Card

Let us know if this helps and good luck with your LabVIEW applications. Sorry to hear about the accident I hope you are feeling well.

Cheers!

Corby_B

http://www.ni.com/support 

[VeritasAequitas]

The hardware configuration I am using consists of a signal conditioning carrier (SC-2345) connected to a data acquisition board (PCI-6040E – also referred as PCI-MIO-16E-4). I am also using LabView 8.20. I have found example problems that came with LabView that deal with sound waves. I believe that the problem most like mine is the one that measures the sound level. I am kind of unsure how to take the sound that the program measures, have the software analyze it and determine if the sound level is in the prefered DB level. Do i need a special microphone to measure decible levels or does any microphone work. I purchased two microphones the data sheets are at these urls.

http://media.digikey.com/pdf/Data%20Sheets/Horn%20Industrial%20PDFs/EM9752U%2047.PDF

http://media.digikey.com/pdf/Data%20Sheets/Horn%20Industrial%20PDFs/EM9745%2044.PDF

[Corby_B]

Hello ajh305,

Thanks for your post back. So about the microphones you have chosen. They don't appear to follow the IEPE standard for excitation so you will have to power these externally by some other means. Although these have very low current consumption (500uA) so you could use the AO ports on your DAQ board to run them. 

Might take a look at this Knowledge Base for more information about microphones.

How to Choose a Microphone for Sound Measurements

As far as analyzing your signals, the signal coming from the microphone is just a voltage so you can analyze that any way you like. The dB functions that Fracisco pointed to are great because it does all the calculations for you. Its part of the sound and vibration tool kit. Do you have this in your lab? The toolkit was specifically designed for sound and vibration applications. If you do not have this there are some functions that can help you analyze your incoming audio signal. Take a look on the functions palette of you block diagram.

Programing >> Waveform >> Analog Waveform >> Measurements.

Introduction to Microphones

Let us know if this helps a bit with your application!

Cheers!

Corby_B

[VeritasAequitas]

I thought we had the sound and vibration toolkit but it won't let me get into it so i may have to stick with functions. Which of these functions would be ideal for me to use for this application? do you have any examples of how these are used?

[Corby_B]

Hello ajh305,

Thanks for your post back!

I am sorry to hear that you do not have the Sound and Vibration toolkit. There are some really great features associated with it. www.ni.com/soundandvibration As for the Analog waveform analysis functions. There are some great examples in the NI Example finder that could help you. This is always a great place to look for some starting point programs. Open LabVIEW and go to Help >> Find Examples. If you do a search for "FFT" there are some examples called "Power Spectrum Measurements.vi" and "Spectrum Measurements.vi" this will help you know what frequencies and how loud they are. Let us know if this helps and good luck with your application!

Also check out the NI Developerzone. Alot of people post code to projects they have done.

Cheers!

Corby_B

http://www.ni.com/support

[VeritasAequitas]

Hello again. I have my microphone powered by 4.5 volts dc with RL being 2.2 K and a 1uF cap. The voltage from the microphone goes into a non inverting amplifier and from there into a active low pass filter. I have the voltage out connected to an Oscope and i was wondering what kind of gain i should have. Right now its a gain of 100. and also how can i design a signal conditioning circuit that will use the full range of the DAQ +10v to -10V. I don't know what voltages i can use to do this because on the Oscope it fluctuates so much. Any help on this would be greatly appreciated.

[Corby_B]

Hello ajh305!

Thanks for your post. So the Gain that you will see is completely dependent on the kind of amplifier that you are using. So a Gain of 100 is not unusual, It seems like the gain you are seeing is in the norm.

So what kind of voltages is your audio device giving you. Maybe using a smaller gain would be better to get you in the +/-10 volt range of your DAQ board. Also you mention alot about noise. Is this noise that you are seeing on top of what sounds you expect to be picking up? Try hitting the microphone with a Constant Wave of a specific frequency in a controlled environment. This could tell you if what you are seeing is noise or a characteristic of the sounds you are picking up. Let me know if this helps!

Why Am I Getting Noisy Measurements with My SC-2345 Signal Conditioning Modules?

Cheers!

Corby_B

http://www.ni.com/support