Sorry if this has already been addressed somewhere on the site, but it struck me (red emphasis, mine):
AKM's two-chip DAC solution that separates the digital aspect from the analog was announced following a period of extensive tests promoted by the Japanese company using controlled listening tests. The results, as the company notes, validated the combination of the AK4191 premium delta-sigma modulator with multi-bit output chip for enhanced digital signal processing capability, when combined with with the AK4498 premium D/A converter with multi-bit modulator data interface, resulting in superior dynamic with vast playback resolution, as well as improved noise immunity and increased low-frequency noise performance.
AKM is now offering this solution for the audio industry, recommending the two-chip solution for high-end audio designs, active speakers, network audio and USB DAC applications. "By using two ICs, AKM has minimized the effects of digital noise within the analog output, resulting in a perceived improvement of the ratio of signal to noise. This improvement, while not easily quantifiable via traditional measurement techniques, is easily experienced during controlled listening tests," the company states.