Yes I have. I own a large collection of high resolution music.
I have sacd players, I have 24bit dacs, I've tried all the formats over the years.
In my experience there is far more to be gained through our hardware choices, than there is in worrying about software formats.
All digital formats suffer the same problem, they lose weight and body, they become anemic, often grey. And there is 2 parts to this, the ADC step and the DAC step.
We're all focussing our energy in addressing the DAC step. But is that the real source of the problem? It's only half of the problem
No one is focussing on the ADC. Sure there might be new chip developments happening, but these manufacturers are focussed on specs, they are focussed on theory and numbers. What companies are focussed on taking the chips and making actual devices? Korg, Weiss, Prism, etc? What are they doing? My impression is they seem to be focussed on the wrong things.
Oz,
There is actually a lot of work being done in the ADC arena, most hi end people are just not aware of it.
The first and absolutely crucial thing to understand is that chip makers will not design an ADC chip that -adds- colour or is euphonic.
Their goal is to accurately reproduce what is going in. I think that is completely understandable and it would be somewhat ludicrous
to do otherwise.
Tape does -not- do this. Tape changes, in a nice way, what goes on to it and this is very well known, at least in pro circles.
Many hi end download labels claim analog tape to be the most accurate storage format. This is simply not true. In many cases
it is the best sounding format but it is not the most accurate format.
OK, once we have established that, then I think it's appropriate to look at what 'damage' each format does to the source, IOW
how each format actually changes the source.
Tape has a lot of interesting effects from reduced resolution, to what some engineers call a 'glue' effect when using many tracks
of a multi track. It also has a LF 'head bump' , or a LF boost, depending on speed and tape type. It also adds a lot of distortion,
mainly 3rd harmonic. Many classic rock records done on analog tape actually exploit the tape compression when hit hard (high levels).
You can hear all this, if you know what to listen for, I certainly can.
Digital is a very different animal. More resolution but also because of that added resolution many very subtle artifacts manifest and
it's often hard to even get a handle on what they are. Here are some of these artifacts:
- Delta Sigma modulator artifacts with non steady signals. ESS (Sabre) identified these and tried to address them in their products
- Digital filter artifacts. In the ADC these are from the decimation filters. All audio ADC's run at around 6MHz with anywhere from 1 to a few
bits and that digital signal is decimated down to whatever PCM format is required.
- Noise floor artifacts. These can be increased noise above 20kHz or actual noise floor modulation with the signal. AKM semiconductor has
done quite a bit of work on this side of things.
- Jitter at the ADC end. Once it is encoded you can't get rid of it, doesn't matter what trickery you do in the DAC. You can probably cover it up a bit.
Just about all pro ADC's need to be able to synchronize to other units when multiple units are running. They do this with word clock, you can
use one ADC as the 'master' and send it's word clock to the 'slave' ADC. Some people also use a 'house clock' and slave everything off it.
This is all good and well but the problem is the ADC chip doesn't run off, for example a 44.1kHz word clock, it requires a much higher freq clock
usually 11.2896MHz or double that. So that HF clock must be made up from the 44.1kHz word clock. They do this with a PLL (Phase locked loop)
which basically means that the internal 11.2896 clock is 'tracking' or 'following' the 44.1kHz external word clock. Designing a very low jitter PLL
system that can track an external WC is very difficult and if you are talking about levels of jitter that say a zen clock has, well there is no
PLL system that can come close. But it's hard to sell a professional ADC that doesn't have a WC input and slave-ability. In an ideal world we
would have settled on one frequency, say 22MHz master clock and just pump that clock around the studio slaving any ADC's directly off it.
One of the reasons I like the Korg MR unit, it has two fixed clocks that can be upgraded to very low jitter units. Much better than a PLL.
OK, you suggest ADC and DAC chip makers don't do much listening to their products, this is not true at all. A -lot- of listening goes
on with these chips. But again - we have to go back to our initial discussion, they are not trying to make their chips sound like an
analog tape machine. They are trying to make the chips reproduce exactly what goes into them accurately. This makes perfect sense
to me.
They will leave any euphonic license to the product designers. And contrary to opinion here there are quite a few very high quality
pro ADC boxes that do add some analog spice from very subtle to not so subtle. In the very subtle variety I would say Forssell
Technologies, not so subtle would be Burl Audio (bomber) JCF Latte etc.
Other top end pro ADC's just want the box to be transparent, an example would be Prismsound, Pyramix Horus, DigAudio Denmark etc.
And if you do a bit of forum trolling, sound engineers are pretty spread across the board WRT which they like to use. Some like ]
very transparent, some like some color.
I can't really say much more, it gets a bit beyond the scope of this forum but suffice to say just slandering pro audio ADC chip
makers and ADC box makers is, IMO complete folly. There are lot's of people out there doing lot's of work trying to get a handle
on the understanding of digital artifacts and how they manifest, it's a complex business. Add to that the whole cost competitive nature
of products and those compatibility issues mentioned and you start to get a clearer picture of why we are where we are.
It's also worth considering that a decent 24 track 2" analog tape machine probably cost well over $50,000 back then and you get
some idea of the challenges. People these days scoff at paying much over $5k for a hi end converter and they usually want 8 ins and
outs for that.
I would suggest just be patient, I'll have that Korg going in a while and I will address most of the issues. The ADC in the Korg is a
true 1 bit design and whilst it doesn't have absolute cutting edge DR figures of over 120dB I don't think that's important. At DSD128
it is a very good converter with very few of the PCM artifacts discussed above.
I could write pages and pages on this whole subject but I'll leave it at that.
As a finishing note, it's worth considering that next year AKM is releasing a hi performance range of converter chips including
DAC's ADC's and Sample Rate / format converters (SRC). They -all- do PCM at 32 bit up to 768kHz (yep) and quad speed DSD256
(11MHz). The format converter converts any format, (DSD or PCM) to any other (DSD or PCM).
So I expect this whole hi rez / DSD episode is just beginning and we may yet see some very interesting products.
cheers
Terry