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While going through hamster's Intro to FPGA & VHDL book (great resource BTW), I had a go at outputting 8-bit audio at 11 KHz through a sigma-delta DAC. It worked, but the audio quality was pretty poor. Yes, 8-bit @ 11 KHz audio is low-fi, but the same audio data is much less noisy when played through a computer's sound-card. The DAC itself was clocked at 32 MHz, which I think should be more than enough for decent quality output. I set myself the goal of improving quality to be similar to a sound-card (without increasing the number of bits or the input sample-rate). So far, I have managed to improve the quality by using a second-order sigma-delta DAC, but it still has crackling noise audible that shouldn't be there. Has anybody else experimented with sigma-delta DACs and 8-bit audio? If so, what kind quality did you get? I'm wondering if there's something wrong with the DAC, or if I should be doing something like digitally low-pass filtering the 8-bit @ 11 KHz audio data before passing it on to the DAC. Hans