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Isolationist tendencies One of the principal design briefs for DAX Discrete was to eliminate any non-harmonic distortion from reaching the analogue outputs. Although all distortions are unwanted, harmonic distortions are spectrally related to the original analogue sounds and the ear is more forgiving of these (especially the low order even-harmonic types). By contrast the ear easily detects and feels uncomfortable with any non-harmonically related sounds. In a dac these come mostly from the digital domain and are inadvertently passed through to the analogue domain and thus onto the power amplifier and speakers. Not so in DAX Discrete. By designing DAX Discrete from the outset to be fully synchronous, then by optically isolating every single feed into the discrete multibit dac and programming excellent stop-band rejection in the DSP digital filters and finally by avoiding kick-through within the dac itself, we are confident that we have prevented all digital non-harmonic distortion from corrupting the delicate audio signal.  Today, by far and away the most commonly used data conversion method in digital audio is Delta-Sigma, although we believe this is for reasons of cost rather than ultimate audio quality. Delta-Sigma converters always produce significant analogue noise which has to be filtered out by unwelcome analogue filters or left intact to degrade the pre/power amplifier combination. Delta-Sigma also relies on noise shaping to move high levels of noise just out of the audio band and facilitate use of a lower frequency clock rate, but even so, the clock rates necessary are very high and make timing in the digital domain extremely susceptible to illusion-destroying jitter distortion. By contrast multibit converters, because they rely partly on amplitude information, their transition timing is far less critical and since in-band resolution is not traded for out-of-band noise, noise shaping is simply not required. When precision built, we believe 'quiet' multibit converters remain state-of-the-art in conversion technology although their cost is necessarily higher - in DAX Discrete the cost is at least 50x that of the most expensive 24/192 Delta-Sigma parts. © 2010 Audio Synthesis |