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Wave audio noise. — Parallax Forums

Wave audio noise.

SexieWASDSexieWASD Posts: 41
edited 2010-10-25 02:28 in Propeller 1
I've been designing a pumpkin this weekend for Halloween. I got Wave audio playback on my uOLED-96-prop with Raymond Allen's PlayWav_16bitStereo.spin, however the sound is quite horrible, I had it running through a LM386N amp, but even directly (except one resistor) into my amplified PC speakers it has a ton of noise. I was wondering what other people have done to either filter or eliminate the noise. It sounds scratchy yet digital, if that makes sense. <-edit: (a lot like bad clipping actually)

I'm sorry if this has been covered already, I've been searching all day for a way to fix it, but haven't had any luck so far.

Comments

  • JonnyMacJonnyMac Posts: 9,208
    edited 2010-10-24 14:08
    I went through this with a commercial product (AP-16+) and Chip Gracey identified the issue and solved it with a small cog. Instead of writing directly to the DACs you write to the hub and let the Stereo_Duty cog take care of the output.

    You can find a demo that fixes the noise issue you're encountering in this thread:
    -- http://forums.parallax.com/showthread.php?t=123900
  • kuronekokuroneko Posts: 3,623
    edited 2010-10-24 17:05
    JonnyMac wrote: »
    I went through this with a commercial product (AP-16+) and Chip Gracey identified the issue and solved it with a small cog.
    I'm curious. Which pins is the AP-16+ using for audio out?
  • SexieWASDSexieWASD Posts: 41
    edited 2010-10-24 17:52
    This is awesome, I've now got it outputting some decent sounding audio clips. I am amazed at this fix, I really had no chance of fixing that on my own.

    @kuroneko
    This line in efx_wavdacs_demo_sd.spin is what I changed to set the pins, by default it's pins 11 and 10.
    duty.start(@lrsamples, 11, 10)                                ' launch duty into cog 1


    Now all I have to do is figure out why it plays the clip twice...

    EDIT: nvm fixed that too, this pumpkin is going to be sweet!
  • kuronekokuroneko Posts: 3,623
    edited 2010-10-24 17:57
    SexieWASD wrote: »
    This line in efx_wavdacs_demo_sd.spin is what I changed to set the pins, by default it's pins 11 and 10.

    Ah, should have read more comments (too early here). Seems that the AP uses the same pin locations as the demo board. Thanks.
  • kellyj994kellyj994 Posts: 1
    edited 2010-10-25 02:28
    JonnyMac wrote: »
    I went through this with a commercial product (AP-16+) and Chip Gracey identified the issue and solved it with a small cog. Instead of writing directly to the DACs you write to the hub and let the Stereo_Duty cog take care of the output.

    You can find a demo that fixes the noise issue you're encountering in this thread:
    -- http://forums.parallax.com/showthread.php?t=123900



    Thanks you for the post.
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