Does Soulution even design their own digital gear? I thought they outsourced all digital to another firm in die Schweiz?
Michael.
Michael.
Rob Watts said:On the WTA filter, yes the WTA algorithm does give roughly the same sound as a conventional half band filter that has ten times the tap length. But I have always said that increasing tap size improves performance,even with using the WTA, and I am certain that 26k is not the limit. You can hear big changes from 16k to 18k; and there was a big change from 18k to 26k. Now there has to be a limit to when the tap size will no longer improve the sound, and if I were to put a number on it (and this is entirely a guess) I would say 1M taps for an 8 times OS filter. That would guarantee accuracy to better than 16 bits, as the sinx/x coefficients are now well below the 16 bit level. But this is a guess. It could be 100K, it might be 10M. Nobody knows. I will find out - that's what makes this so interesting at the moment.
Rob Watts said:1. PCM Pro: excellent resolution of small signals, very small signals do not disappear into the dithered noise floor.
Cons: Timing. Ear/brain can resolve 4uS, CD innately is at 22uS.
2. DSD Pro: Samples at 0.34 uS, albeit at not very good resolution, so has much better timing innately
Cons: resolution. Noise shaper noise is not the same as dithered noise, any signal below noise shaper noise floor is lost.
Now the timing issue can be resolved by the DAC interpolation filter, and with an infinite tap length filter, timing is completely reconstructed. So red-book is capable of very much better performance, if you improve the interpolation filter. But with DSD, the encoding means that low-level details are lost in the noise shaper noise floor, and they are lost forever. So DSD has a compression in depth and instrument separation, due to poor resolution, but does not innately have timing problems. Check out 2L website, and compare the DXD recording to the DSD64 or DSD128 - to my ears, the loss in transparency of DSD is not small.
Getting back to design of the DAC. Now I run my DAC's with a very simple single stage active analogue section, with only 2 caps and 2 resistors in the direct signal path - and I do this for transparency. But this means the digital RF noise in the 100k to 1M band must be very low, so the digital source must be filtered - and DSD is at -20dBFS at 100kHz. So I can't put raw DSD into the DAC, or it will sound very hard. So the DSD is filtered, which converts it to regular PCM.
If I were doing a DAC for only DSD would I do it this way? Yes, I think I would, as simple analogue is always the best.
Incidentally, the DSD filters on Hugo has been improved - they are much smoother than with Qute.
Soulution appear to have an excellent industry reputation, but I can't help feeling that if this is all there is to their zero-phase technology, it is as you suggest above. Adding to the hype, is the press report by Alan Taffel (see thread post #15) where, after a demonstration of the technology, he wrote the following: "Based on what I heard, the Soulution phase shift cancellation circuit could be a watershed development in digital sound evolution..."
Perhaps, there is more to the technology than is indicated in the Soulution press release?
the latest absolute sound mentions a new Soulution DAC with 'phase correction' that is the new BREAKTHROUGH paradigm for digital playback.
supposedly, on/off tests for the soulution DAC with and without 'phase correction' is "insert your favorite term for &*! unbelievable here".
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