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Thread: Audio Recorder, Can't Hear Playback

  1. #1

    Audio Recorder, Can't Hear Playback


    This is my very first test with the Teensy Audio Library so probably just make a basic error.

    Simply, can't hear any playback from the recording in the Recorder Example. I have tested audio both out of the headphones and the Line Out with a 0.5W speaker.

    All the buttons seem to be working fine (Stop, Play, Record). I checked the SD card and the file RECORD.RAW was written. So it must be something with my mic or output?

    Here is the circuit if it helps:
    Click image for larger version. 

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    Thanks x100

  2. #2
    Senior Member+ Frank B's Avatar
    Join Date
    Apr 2014
    Germany NRW
    You can not connect a speaker to lineout.
    Linout is to connect an ampilifier.
    The easiest is probably to connect active PC-Speakers.
    Then, try the other examples and first test if you hear something.
    Try headphones, too.

  3. #3
    Ah yes okay I will connect the line to some amplification and try again.

    I tried headphones. Any reason why I could not hear anything through headphones? Is there a way in the code to specify line-out versus headphones? Or is it always outputting to both?


  4. #4
    Senior Member+ Frank B's Avatar
    Join Date
    Apr 2014
    Germany NRW
    If the examples do not work, there is something wrong with your hardware. Check the soldering and such things..
    Use the guitar example.

  5. #5
    Senior Member
    Join Date
    Nov 2012
    The connections to the Teensy's power and ground look to me like you have just stuck the jumper pins in the holes without any solder.
    Click image for larger version. 

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    There also appear to be other connections to the boards which are done like this.
    Connections to those pins on the boards MUST be soldered.


  6. #6
    It's working well now. Added a 2.5W amplifier to the line out. And most importantly, hooked up an AGC microphone module, which eliminated all the noise.

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