For those that would like to read more about the inherent differences and benefits of PCM VS DSD you can read more at Wikipedia. Apparently DSD does not have a clear cut advantage over PCM sound quality and actually has greater noise content at higher frequencies (20khz an up) than PCM. I have not yet auditioned a DSD recorder so can not say first hand if they are in fact superior. i plan on giving it a try and comparing it to 24/192 pcm using an external a/d input. My current a/d provides -135 db s/n ratio which is significantly better performance than the recorder offers. for this reason alone I feel it is worth staying with PCM 24/192 until something better rolls down the pike!
DSD vs. PCM
There has been much controversy between proponents of DSD and PCM over which encoding system is superior. Professors Stanley Lipshitz and John Vanderkooy from the University of Waterloo, in Audio Engineering Society Convention Paper 5395 (2001), stated that 1-bit converters (as employed by DSD) are unsuitable for high-end applications due to their high distortion. Even 8-bit, four-times-oversampled PCM with noise shaping, proper dithering and half data rate of DSD has better noise floor and frequency response. However, in 2002, Philips published a convention paper arguing against this in Convention Paper 5616[dead link]. Lipshitz and Vanderkooy's paper has been criticized in detail by Professor Jamie Angus at an Audio Engineering Society presentation in Convention Paper 5619[dead link]. Lipshitz and Vanderkooy responded in Convention Paper 5620.
There are fundamental distortion mechanisms present in the conventional implementation of DSD.[17] These distortion mechanisms can be alleviated to some degree by using digital converters with a multibit design. Historically, state-of-the-art ADCs were based around sigma-delta modulation designs. Oversampling converters are frequently used in linear PCM formats, where the ADC output is subject to bandlimiting and dithering (Hawksford 1995). Many modern converters use oversampling and a multibit design. It has been suggested that bitstream digital audio techniques are theoretically inferior to multibit (PCM) approaches: J Robert Stuart notes,[18] "1-bit coding would be a totally unsuitable choice for a series of recordings that set out to identify the high-frequency content of musical instruments, despite claims for its apparent wide bandwidth. If it is unsuitable for recording analysis then we should also be wary of using it for the highest quality work."
When comparing a DSD and PCM recording of the same origin, the same number of channels and similar bandwidth/SNR, some still think that there are differences. A study conducted at the Erich-Thienhaus Institute in Detmold, Germany, seems to contradict this, concluding that "hardly any of the subjects could make a reproducible distinction between the two encoding systems. Hence it may be concluded that no significant differences are audible."[19]
In the popular Hi-Fi press, it had been suggested that linear PCM "creates [a] stress reaction in people", and that DSD "is the only digital recording system that does not [...] have these effects" (Hawksford 2001). This claim appears to originate from a 1980 article by Dr John Diamond entitled Human Stress Provoked by Digitalized Recordings.[20] The core of the claim that PCM (the only digital recording technique available at the time) recordings created a stress reaction rested on "tests" carried out using the pseudoscientific technique of Applied Kinesiology, for example by Dr Diamond at an AES 66th Convention (1980) presentation with the same title.[21] Diamond had previously used a similar technique to demonstrate that rock music was harmful due to the presence of the "stopped anapestic beat".[22] Dr Diamond's claims regarding digital audio were taken up by Mark Levinson, who asserted that while PCM recordings resulted in a stress reaction, DSD recordings did not.[23][24][25]
A double-blind subjective test between high resolution linear PCM (DVD-Audio) and DSD did not reveal a statistically significant difference.[26] Listeners involved in this test noted their great difficulty in hearing any difference between the two formats.
