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    Recording sound in range of 0- 150 kHz frequencies

    Hello Dear Friends

    I want to record and playback sounds in range of 0- 150 KHz frequency and I want to use any microcontrollers of ARM series.

    I have some questions:

    1. How much should sampling frequency of ADC be?
    2. Can I use ICs like VS1053? Does this IC support 0-150KHz frequency?
    3. Can I directly save recorded sound on SD Card with VS1053?
    4. Which microcontroller is appropriate for this project? What is your idea?

    Thanks for your attention.

    •   Alt2nd December 2016, 19:31

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    Re: Recording sound in range of 0- 150 kHz frequencies

    To capture airborne sounds you need a suitable transducer (or microphone). Do you have a transducer that responds up to 150 kHz ?

    The sampling rate should be 300k, or twice your desired frequency.


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    Re: Recording sound in range of 0- 150 kHz frequencies

    300 kS/s is the minimal sampling rate according to Nyquist theorem. Practically, there must be a margin between the highest signal frequency and fs/2 to allow feasible anti-alias filters. 330 to 350 kS/s is more realistic.

    Regarding VS1053, just review the datasheet. It's maximum sampling rate is 48 kS/s. Maximum sampling rate of high performance audio ADCs is 192 kHz or slightly higher, not suitable for 150 kHz signal bandwidth.

    You didn't yet mention intended ADC resolution respectively recorded dynamic range.


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    Re: Recording sound in range of 0- 150 kHz frequencies

    The hardest part of this problem won't be the ADC, but rather finding a transducer with a reasonably flat frequency response over the entire 0 - 150kHz range. I don't know of any such transducers, so if such piezoelectrics exist then expect them to be very expensive.


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    Re: Recording sound in range of 0- 150 kHz frequencies

    Some digital oscilloscopes and fast data loggers can easily sample at that rate.
    I suppose it depends on how long you wish to record for, milliseconds or hours ?
    Cheers, Tony.


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    Re: Recording sound in range of 0- 150 kHz frequencies

    Quote Originally Posted by BradtheRad View Post
    To capture airborne sounds you need a suitable transducer (or microphone). Do you have a transducer that responds up to 150 kHz ?

    The sampling rate should be 300k, or twice your desired frequency.

    I need to use a microphone for recording sounds.

    But I don't know exactly what features should this microphone have?

    - - - Updated - - -

    Quote Originally Posted by FvM View Post
    300 kS/s is the minimal sampling rate according to Nyquist theorem. Practically, there must be a margin between the highest signal frequency and fs/2 to allow feasible anti-alias filters. 330 to 350 kS/s is more realistic.

    Regarding VS1053, just review the datasheet. It's maximum sampling rate is 48 kS/s. Maximum sampling rate of high performance audio ADCs is 192 kHz or slightly higher, not suitable for 150 kHz signal bandwidth.

    You didn't yet mention intended ADC resolution respectively recorded dynamic range.
    I want to use STM32F103 microcontroller. According to it's datasheet,it has 12bit ADC and 1MS/S sampling rate. Is STM32F103 a good choice?

    - - - Updated - - -

    Quote Originally Posted by Warpspeed View Post
    Some digital oscilloscopes and fast data loggers can easily sample at that rate.
    I suppose it depends on how long you wish to record for, milliseconds or hours ?
    The device should be portable something like cellphones or recorders.
    I want to record for hours and save data on SD card and play it again.
    Last edited by nadiro; 3rd December 2016 at 10:39.



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    Re: Recording sound in range of 0- 150 kHz frequencies

    I need to use a microphone for recording sounds.

    But I don't know exactly what features should this microphone have?
    Suggests that you have no actual clue why and how you want record sound with "0 - 150 kHz frequency" range. What's the purpose of recording ultrasound? Or is 150 kHz just a typo?

    I think the point should be clarified before discussing other details. Microphones with 150 kHz frequency range are available but cost a small fortune.



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    Re: Recording sound in range of 0- 150 kHz frequencies

    Quote Originally Posted by FvM View Post
    Suggests that you have no actual clue why and how you want record sound with "0 - 150 kHz frequency" range. What's the purpose of recording ultrasound? Or is 150 kHz just a typo?

    I think the point should be clarified before discussing other details. Microphones with 150 kHz frequency range are available but cost a small fortune.

    My purpose is recording and playing back the sounds of different animals which is out of human hearing range.

    Consider the table below:
    Click image for larger version. 

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ID:	134109



    •   Alt3rd December 2016, 13:07

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    Re: Recording sound in range of 0- 150 kHz frequencies

    There is a method to translate bat squeaks (ultrasonic range), down into a range which the human ear can detect. The operating principle is called heterodyning. Try an internet search for 'bat listener'. There may be suitable microphones which can pick up frequencies in the ultrasonic range, yet are not too expensive.



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    Re: Recording sound in range of 0- 150 kHz frequencies

    I really appreciate your helps

    Do you have any idea about choosing suitable microcontrollers and their A/D & D/A ?



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    Re: Recording sound in range of 0- 150 kHz frequencies

    There is a chapter in the 1977 National Semiconductor pressure transducer handbook that refers to microphone applications of pressure transducers.

    They suggest a frequency response of dc to 30-50 Khz is possible.

    Its interesting because they mention hydrophone applications and use of parabolic reflectors.

    These only cost a few dollars, and already have a built in preamplifier, so might be worth a try initially.
    Click image for larger version. 

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    Here is a download of that entire book.
    Chapter 12 is what you want.
    http://bitsavers.trailing-edge.com/p...r_Handbook.pdf
    Last edited by Warpspeed; 3rd December 2016 at 21:17.
    Cheers, Tony.


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    Re: Recording sound in range of 0- 150 kHz frequencies

    Many years ago, I helped an acquaintance to build an heterodyne type wildlife listener. It was not my design, it was a kit which I assisted to build.

    Listening at night is fascinating. One of course can hear crickets and other small insects chirping.....but there are other noises at ultrasonic range too.
    My batteries are recharged by "Helpful Post" ratings.
    If you feel that I've helped you, please indicate it as a Helpful Post


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    Re: Recording sound in range of 0- 150 kHz frequencies

    Quote Originally Posted by Warpspeed View Post
    There is a chapter in the 1977 National Semiconductor pressure transducer handbook that refers to microphone applications of pressure transducers.

    They suggest a frequency response of dc to 30-50 Khz is possible.

    Its interesting because they mention hydrophone applications and use of parabolic reflectors.

    These only cost a few dollars, and already have a built in preamplifier, so might be worth a try initially.
    Click image for larger version. 

Name:	microphone.jpeg 
Views:	3 
Size:	65.1 KB 
ID:	134127

    Here is a download of that entire book.
    Chapter 12 is what you want.
    http://bitsavers.trailing-edge.com/p...r_Handbook.pdf
    Thank you for your suggestion and introducing the book.

    - - - Updated - - -

    Quote Originally Posted by schmitt trigger View Post
    Many years ago, I helped an acquaintance to build an heterodyne type wildlife listener. It was not my design, it was a kit which I assisted to build.

    Listening at night is fascinating. One of course can hear crickets and other small insects chirping.....but there are other noises at ultrasonic range too.
    Thank you for sharing your experience with us. Do you have any other information about that project?



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    Re: Recording sound in range of 0- 150 kHz frequencies

    Thinking about this a bit more...

    Probably the most suitable commonly available low cost microphone might be the electret type. These work from below 20Hz to around 30 Khz and are quite sensitive.

    They will not go to zero frequency as the previously mentioned pressure transducer will, but otherwise it might be your best starting out point for this project.
    That, and a parabolic reflector should give you an sensitive and very directional microphone.
    A microwave dish might be best, and these come in all sizes up to really huge things.

    http://www.openmusiclabs.com/learnin...t-microphones/

    http://mintakaconciencia.net/squares/parabolic-mic/
    Cheers, Tony.



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    Re: Recording sound in range of 0- 150 kHz frequencies

    Knowles has an ultrasonic enhanced MEMS microphone with 80 kHz bandwidth which is often used for wildlife audio recordings according to literature.
    http://www.knowles.com/eng/content/d...PU0410LR5H.pdf

    For the requested 150 kHz bandwidth, I'm only aware of expensive Bruel & Kjaer microphones. https://www.bksv.com/~/media/literat...ta/bp2030.ashx

    Playback of wideband ultrasonic recordings with sufficient level is even more challenging.



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    Re: Recording sound in range of 0- 150 kHz frequencies

    Quote Originally Posted by Warpspeed View Post
    Thinking about this a bit more...

    Probably the most suitable commonly available low cost microphone might be the electret type. These work from below 20Hz to around 30 Khz and are quite sensitive.

    They will not go to zero frequency as the previously mentioned pressure transducer will, but otherwise it might be your best starting out point for this project.
    That, and a parabolic reflector should give you an sensitive and very directional microphone.
    A microwave dish might be best, and these come in all sizes up to really huge things.

    http://www.openmusiclabs.com/learnin...t-microphones/

    http://mintakaconciencia.net/squares/parabolic-mic/

    Dear Warpspeed, I am very thankful.
    I will study this pages. How wonderful dish microphones are!

    - - - Updated - - -

    What is your idea about the appropriate speaker and related circuits?
    Is there any speaker which supports this rang of bandwidth?



    •   Alt5th December 2016, 09:10

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    Re: Recording sound in range of 0- 150 kHz frequencies

    What is your idea about the appropriate speaker and related circuits?
    Is there any speaker which supports this rang of bandwidth?
    Do you have a rough idea of produced sound level and intended "speaker" directivity?

    - - - Updated - - -

    As a first guess, only plasma speakers are able to reproduce wideband sound above 100 kHz. Electrodynamic ribbon tweeters are good up to about 40 kHz, but have probably unwanted frequency dependent directivity. Electrostatic speakers might even go higher, but with extreme directivity due to the large transducer area. Low level sound generation is easier because it can use very small electrostatic transducers.



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