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Re: [softrock40] Quisk louder audio workaround

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  • Chris Albertson
    ... Certainly that can work. But when you multiply a digital audio signal you are effectively also increasing the quantization noise. The way to think about
    Message 1 of 615 , Jun 2, 2009
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      > I have a workaround working now:  I modified the Quisk source file sound_alsa.c to amplify all the sound output samples by 40x.  So now the audio is "loud & clear" :-)

      Certainly that can work. But when you multiply a digital audio signal
      you are effectively also increasing the quantization noise. The way
      to think about it is that before the audio values were say from 0 to
      30 and to low to hear, now they are from 0 to 1200 and much loader but
      there still are only 31 unique numbers used in the range of 0 to 1200.
      It is still only 5-bit audio.

      The better way to is multiply farther downstream, the closer to the
      source the better.

      The best way is to adjust the gain of the amplifier either on the SR40
      or on the audio interface. (All of the better audio interfaces have a
      gain knob that gives about 40db of adjustment range and then there are
      also LEDS or a UV meter to assist setting the level.) The goal should
      be to have the analog signal fully "cover" the range of the A/D chip
      so as to take advantage of all the available bits



      --
      =====
      Chris Albertson
      Redondo Beach, California
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      Message 615 of 615 , Feb 5
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