Several of you have written me asking about multi-bit DACS. You now understand how a 1-bit system works, relative to a 16, 24 or even a 32 bit setup but what's a 6-bit DSD? If there's only 1-bit in the output and that output gets more of the same or less of the same, what's about this 6-bit business? It is true, as I mentioned earlier, that modern "1-bit" sigma delta DACS and ADC's are actually 6 "bits" and there are few true 1-bits out there. But here's the thing: at their output there's still only 1-bit, running at 2.88MHz (64 times 44.1kHz), and no extra room for 5 more bits. In fact, if you were to look at the output of a 1-bit DSD converter vs. a 6 bit DSD converter it would look the same. So everything we learned about how this DSD business works is still accurate. The only missing piece of information is how accurate the DSD stream is. How faithful to the original musical signal is it? That's determined by the number of bits used to encode and the speed of the 1-bits buzzing by. These extra "bits" are the number of sigma delta converters used to encode and decode with greater fineness. In the end, their decisions are all narrowed down to represent the music as perfectly as they can.
Our new A/D Converter, shipping out next week, uses just such a multi-bit DSD converter to great advantage and one of those advantages is we do not need a brick wall filter on its input. Instead we are able to place a gentle 6dB/octave low pass filter on the input of the converter that STARTS its rolloff at 80kHz. There's been great progress in A/D and D/A converters over the years and this latest crop of "1-bit" architecture DACS and converters represents the state of the art well.
