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RE: You May Express Your Dismay

Posted by Peter Qvortrup (M) on August 27, 2015 at 03:03:14

In Reply to: RE: You May Express Your Dismay posted by Mr_Steady on August 26, 2015 at 12:05:03:

Dear Jamie,

I do, certainly based on what I have heard from all the alternative so called higher resolution formats none of which to my ear and in my system (which unsurprisingly is very high level all Audio Note) DSD and every other supposedly higher resolution system and I have had the opportunity to try most of them come close to the best I get from Redbook, one of the "perks" of my job I suppose you could say, or perhaps a curse?

One of the most experienced technical reviewers, Martin Colloms wrote this in his review of our top level (Level Six) CD transport and DAC, complete review here,

http://www.audionote.co.uk/articles/Audionote_CDT6-Dac_5_complete.pdf

"Sound Quality

As those who know me are well aware, I am rarely
lost for words, but in this case it was some time
before I dared commit my thoughts to paper. Value
for money is inevitably an element in the balancing
and weighing up processes of any appraisal, and
was clearly going to be a significant factor here. Yet
during each listening session - and there were many
considerations of value simply went right out of
the window.
The sound quality was consistently overwhelming,
almost defying critical opinion, constantly
demanding ones attention with the beautiful sounds
it rendered from digital sources. An opinion on a
medium can only be as good as your latest and best
experience: whatever we may have considered was
the limit for CDs Red Book 16-bit/44.1kHz format
and its historic recordings, that barrier has now been
comprehensively overturned."

Martin rated the CDT Six/Fifth Element combination higher than any of the hi-rez formats he had heard, so I/we are not completely alone in our view here.

Our view is that Redbook has the information, but execution across pretty much the entire spectrum of available Redbook products past and present have been badly executed to put it politely.

Having spent the last couple of years or more experimenting with discrete resistor ladder DACs (R2R) what I can confidently say is that Redbook has even further to go, although the improvements possible in the R2R DAC may also benefit some hi-rez.

The picture above shows our unique resistor testing and matching machine which one of our engineers built from scratch last year, it allows us to match up Tantalum, Ni-Chrome and other resistors in a constant temperature environment to the required 0.001% tolerance needed to create the sets of 96 resistors needed in an R2R ladder DAC to get 16Bit.

We are hoping this level of automation of the selection process will allow us to draw down the price of R2R ladder DACs to well below Level Four.

The way our R&D looks so far there is not much point going beyond 16Bit, but there is still some way to go in our work so perhaps I should be careful what I say?

I am curious to know how many different Redbook and Hi-Rez/DSD replay systems you have actually listened to, to get to the conclusions you draw about the order of quality of digital sources, Jusbe makes several good and valid points about "improving" existing digital recordings and knowing how a CD or DSD is derived is not always clear, which further complicates making firm and wide ranging judgements about quality.

May I also remind you that the enormous rise in the sales and interest in the LP really only happened quite some time after Redbook had already started declining, and is, in my opinion, partly at least, a reaction to the paltry quality of what is said to be better quality replacements (read here DSD and Hi-Rez digital sources), so perhaps that is a further illustration that we are not alone in the view that the claims of better are as flaky as I believe they are?

You cannot make a claim as broad and seemingly conclusive as you do about the quality ranking of 16/44 Redbook and Hi-Rez and DSD unless you have tried the widest possible alternatives, and that most certainly includes our DACs and CD transports, it is not a credible claim unless you have.

You say 16/44 is limited and that is of course quite true, in an absolute sense all formats are compromises, I am reminded of a meeting I attended at SONY's technical department in the early 1990's where the "Father of 16Bit", whose name now escapes me, came out of retirement for an interview with a couple of UK journalists; when asked the question what do you use for music at home he proudly announced, "why LP of course!" which prompted the next question "why not CD?" with a big smile he said, "Ah, but digital is for commercial, analogue is for music!"

I asked him about why he had chosen 16Bit and he explained that 16Bit allows for the highest density of data given what is possible to get into the digital domain from an analogue master and mathematically or technically this could not be improved on.

I have always wondered what exactly he meant by this, so a few years ago I asked a customer/friend who is a well-regarded Physicist and mathematician, he shrugged and said he would look into this, several years later he came back and told me that there may actually be some truth in this, as some kind of mathematical "equilibrium" seems to occur around 16Bit 44KHz if you look at sets of complex numbers in 20 - 20kHz set of wave forms, so perhaps there is something in this.

I looked at the data sheet for the AD5791, not very informative, it looks like a DC accurate instrumentation DAC, the AD1865 we use is a multibit 18Bit R2R ladder design, but the discrete 16Bit R2R ladder prototype absolutely obliterates it sonically and I mean makes the already very good DACs in our range sound like a car with a flat tyre, so there is far more going on here than just the bit rate.

I see no real contradiction in your preference for SET and horns and your somewhat confused relationship to digital sources, widen your experience in this area and you may well find yourself in less disagreement with me.

Sincerely,
Peter Qvortrup

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