Arduino Audio DAC Options
In this article David  play around the code Michael Smith created for a PWM based DAC. David  modified his code so that other DAC options could be tried. David  compare the 8-Bit PWM DAC with the R2R DAC at various numbers of bits. You might be surprised at how well a 4-bit DAC sounds. This article includes several sound samples for the various DAC options and demonstrates some software abstraction that allows for multiple DAC options.
   Arduino Audio DAC Options
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