Slawa Roschkow of SW1X has chosen the R2R architecture over Sigma Delta. Here are his words on the subject:
“It is true, the specs of Delta Sigma (DS) chips may look better on paper. In practice, however, they are incomparable to R2R. The stated accuracy numbers of DS DACs are post modulation (after digital filtering has been applied) and are not always attainable in practice for a number of reasons (such as quality of power supplies and imperfections of components & materials, which apply to both R2R and DS) even if your recording comes in the HD PCM or DSD format (which is a modulated 1bit pink noise). One must admit that oversampling, demodulation and noise shaping is a clever concept to manipulate the digital signal carrying musical information. Yet in practice there is no free lunch - all digital signal manipulation comes at a cost - musicality that is. Since part of the Delta Sigma conversion process (similar to switched power supplies) is a high frequency pink noise, it requires a lot of digital filtering or oversampling and noise-shaping. Essentially, oversampling is a corrective process, which needs to sort the digital data in the signal and come up with bits that are not a part of the original data stream. These bits are missing information we do not have (not part of the recording), so they need to be invented (a process called interpolation) and then noise-shape filtered. Noise-shaping and over-sampling are essentially adding artificial information (artifacts) not present in the original samples. All that noise (the reason why it is called noise shaping) with additional artifact samples (which are not part of the original recording) are filtered with a demodulator which relies on the reduced original data by means of a negative feedback loop. The claimed resolution of a DS DAC is of its demodulator after all the digital filtering and not of the data stream itself (which is nothing but noise, please refer to the picture below). In a nutshell, all DS DACs produce filtered noise (which requires demodulation), which we perceive as a sound after a corrective digital filtering (in over-sampling) is applied. Now that sound could be characterized as clear with a lot of perceived details, however at the same time the music tends to sound synthetic & flat without coherence and precision without exception regardless which interpolation algorithm is used. Music however is more than just a collection of noise reconstructed sounds” Read the entire article here.
“It is true, the specs of Delta Sigma (DS) chips may look better on paper. In practice, however, they are incomparable to R2R. The stated accuracy numbers of DS DACs are post modulation (after digital filtering has been applied) and are not always attainable in practice for a number of reasons (such as quality of power supplies and imperfections of components & materials, which apply to both R2R and DS) even if your recording comes in the HD PCM or DSD format (which is a modulated 1bit pink noise). One must admit that oversampling, demodulation and noise shaping is a clever concept to manipulate the digital signal carrying musical information. Yet in practice there is no free lunch - all digital signal manipulation comes at a cost - musicality that is. Since part of the Delta Sigma conversion process (similar to switched power supplies) is a high frequency pink noise, it requires a lot of digital filtering or oversampling and noise-shaping. Essentially, oversampling is a corrective process, which needs to sort the digital data in the signal and come up with bits that are not a part of the original data stream. These bits are missing information we do not have (not part of the recording), so they need to be invented (a process called interpolation) and then noise-shape filtered. Noise-shaping and over-sampling are essentially adding artificial information (artifacts) not present in the original samples. All that noise (the reason why it is called noise shaping) with additional artifact samples (which are not part of the original recording) are filtered with a demodulator which relies on the reduced original data by means of a negative feedback loop. The claimed resolution of a DS DAC is of its demodulator after all the digital filtering and not of the data stream itself (which is nothing but noise, please refer to the picture below). In a nutshell, all DS DACs produce filtered noise (which requires demodulation), which we perceive as a sound after a corrective digital filtering (in over-sampling) is applied. Now that sound could be characterized as clear with a lot of perceived details, however at the same time the music tends to sound synthetic & flat without coherence and precision without exception regardless which interpolation algorithm is used. Music however is more than just a collection of noise reconstructed sounds” Read the entire article here.
