Fan Noise cancelling Issue

Hi ADI's

One of my customers is considering developing a fan noise reduction solution.

she wants to reduce fan noise on equipment (air purifier) to reduce noise in work area.

The devices under consideration are planned to be placed next to the already installed equipment.
I think it should be designed in such a way that it receives the fan noise from the side and generates the opposite phase noise.

So I'm trying to design an ADAU1772 ANC part

Question

1. Is the output of the ADAU1772 the opposite phase of the noise signal? Or is it a noise-canceled signal?

2. Is there any other solution available besides the ADAU1772 assuming that I know the noise frequency?

   

Thank you in advance

Parents
  • +1
    •  Analog Employees 
    on Mar 26, 2019 6:53 PM

    Hello Andrew,

    I think technically this is very difficult to do. Fan noise has a lot of higher frequency signals and they are somewhat random. This is all very difficult to cancel out in an acoustic environment. The wavelengths are short so the amount of cancellation will differ with the angle between the source and the speaker differs depending on where the listener stands. 

    As far as your questions, The 1772 will output whatever signal you would like to output. Normally this part is used to drive headphones so the output is the noise cancelled signal. However, nothing is stopping you from just developing the cancellation signal and sending that out without the original signal. 

    We have the acoustic noise canceller and the noise reduction algorithms that we license for the ADAU1452 family of parts. It is available in trial form in SigmaStudio. The 1452 had PDM inputs so it can receive audio from a PDM output microphone. Then you can interface it with a codec for other inputs and outputs. The ADAU1372 would be a good choice. It is basically the converters from the 1772 without the DSP. 

    Dave T

Reply
  • +1
    •  Analog Employees 
    on Mar 26, 2019 6:53 PM

    Hello Andrew,

    I think technically this is very difficult to do. Fan noise has a lot of higher frequency signals and they are somewhat random. This is all very difficult to cancel out in an acoustic environment. The wavelengths are short so the amount of cancellation will differ with the angle between the source and the speaker differs depending on where the listener stands. 

    As far as your questions, The 1772 will output whatever signal you would like to output. Normally this part is used to drive headphones so the output is the noise cancelled signal. However, nothing is stopping you from just developing the cancellation signal and sending that out without the original signal. 

    We have the acoustic noise canceller and the noise reduction algorithms that we license for the ADAU1452 family of parts. It is available in trial form in SigmaStudio. The 1452 had PDM inputs so it can receive audio from a PDM output microphone. Then you can interface it with a codec for other inputs and outputs. The ADAU1372 would be a good choice. It is basically the converters from the 1772 without the DSP. 

    Dave T

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