Hi Resolution Audio article which may be helpful..

[RGA]

for those trying to figure out which DACs to get.

Audial :: USB 2010 (page 1)

As an aside some of the big designers in this field - the head of AMR "DSD is a single bit, 128 times oversampled format with extreme amounts of noiseshaping added. Some people (including myself) consider it "defective by design".../...DSD is precisely such a 2-Level system with 128 possible values for a 22.7uS Sample period (that is CD), in other words it is a 7 Bit - 44.1KHz equivalent natively, without noise-shaping. This is well below what CD is actually capable of.

And noise-shaping in Digital systems is equivalent (but much larger in magnitude especially for single bit systems) to what I like to call "fuzzy distortion" in looped feedback circuits.../...Many modern DAC's do replay DSD/SACD, however most add digital filters to the DSD stream to clean up at least some of the noise, with predictable results. Anyway you need a DAC Chip that is designed to handle DSD in order to play back DSD.

Or you need to convert DSD to PCM, which to me suffices with 88.2KHz sample rate and 20 Bit to contain all actual information in DSD (as opposed to the all the supersonic noise from the noiseshaping), but is considered by the current bunch of DSD advocates a major lese majesty and utter heresy (Ed Meitner took the same view and some of earlier SACD Players in fact converted DSD to double speed CD Standards PCM).

At any extent, you can now use 176.4KHz and 24 Bits, so you are guaranteed to loose nothing except the ultrasonic noise, which seems to be what DSD fan's really like (I know, another utter heresy). Several Software Players now exist that can transcode DSD on the fly to PCM during playback, so no need to convert the File itself. The same can now also be applied to decoding HDCD, though I personally transcoded all my HDCD's to 20Bit/44.1KHz PCM."



I'm getting a headache.

[Feanor]

Yes, the DSD vs. PCM thing has always been beyond my technical comprehension. Frankly I'd be happy with either -- as I would with hi-rez DTS and/or Dolby Digital.

Going back to early DVD-A vs. SACD days, technical opinion seems to favor DVD-A, i.e. PCM at 24/96 or 24/192. SACD became predominant (relatively speaking) mainly on account of the labels that adopted it.

Sir Terence has mentioned the professional format, DXD, which is PCM at 24/352.8. But apparently there are higher rez DSD formats, viz. DSD-wide and DSD Pure whose virtues I don't pretend to know or understand.

I have a few dozen SACDs. I can't appreciate them fully in my stereo system on account of my crummy old player; I can listen to them multi-channel in my HT system but the amp & speakers lack the resolution of fully appreciate them.

I have some hi-rez downloads from HDTracks. Based on limited examples these file sound better for sure than CD (in my stereo system). Most are SACD rips to 24/88.2, so I don't know what that tells us.

[Sir Terrence the Terrible]

Yes, the DSD vs. PCM thing has always been beyond my technical comprehension. Frankly I'd be happy with either -- as I would with hi-rez DTS and/or Dolby Digital.

Going back to early DVD-A vs. SACD days, technical opinion seems to favor DVD-A, i.e. PCM at 24/96 or 24/192. SACD became predominant (relatively speaking) mainly on account of the labels that adopted it.

Sir Terence has mentioned the professional format, DXD, which is PCM at 24/352.8. But apparently there are higher rez DSD formats, viz. DSD-wide and DSD Pure whose virtues I don't pretend to know or understand.

I have a few dozen SACDs. I can't appreciate them fully in my stereo system on account of my crummy old player; I can listen to them multi-channel in my HT system but the amp & speakers lack the resolution of fully appreciate them.

I have some hi-rez downloads from HDTracks. Based on limited examples these file sound better for sure than CD (in my stereo system). Most are SACD rips to 24/88.2, so I don't know what that tells us.

DSD pure is just basic DSD edited completely in the DSD domain on a DAW.Can't really do much except edit before the system runs out of resources. So it is edited at 1bit 2.8224 MHz all through the process. DSD wide is DSD 8bit 2.8224 Mhz which allows for equalization, balancing, panning, and has the overhead room to process it, and then return it to a standard DSD stream.

You can either record in DXD, or us it as a editing tool(balancing, panning, editing, EQ) for DSD.

There is also double rate DSD128 which is also a 1 bit system but operates at 5.6Mhz instead of the normal 2.8224Mhz of standard DSD.

All of the DSD variants are really recording side formats, as all lead back to basic DSD after all post processing is done.

[StevenSurprenant]

Great article!

One of the more interesting points he made, from my perspective, is how filtering affects what we hear, i.e...

However, this intuitively still a bit bizarre looking response corresponds pretty well to some subjective qualities, traditionally associated to the transient response of the system. Namely, all the brickwall FIR filtered digital systems that I've heard up to date, had big problems conveying natural decay and space, and timbre. In addition, they are prone to boost intense and echoing, false"details", which is rather only imitation of desirable system's ability to convey unrestrained resolution, which should appear within the overall coherent artists' performance. And there was no brickwall filtered digital system that was able to convey natural sound stage, with precise instruments positioning, and natural instruments dimensions. Instead of such a natural space, they boost artificial reverberation of undefined spaciousness, which often swamps the instruments themselves.

Twice, I've heard soundstaging that was extremely defined, where you could see where people were on the stage and believe that you could walk between them. This was about 17 years ago and the gear they used was Theta Digital on one system and Spectral on another. I have no idea of the technical aspects of either piece. Both times this was with a CD provided by the store owner, which I assume, at that time, was bluebook.

All the other very good CD playback units I auditioned didn't produce such pinpoint imaging, but did well at creating a layering effect from front to back. On a good CD recording, that's what I normally hear at home. Another way of saying this is that with the Theta and Spectral gear, I could see the "space" between each instrument and with the other gear, not so much.

[Sir Terrence the Terrible]

Rather than looking at imaging in a vacuum, one has to understand the proper microphone setup has to be used to achieve the effect. If some CD do not produce pinpoint imaging, it is likely the microphone setup does not allow for the effect to exist, or it minimizes it. The reality is, there are plenty of well recorded classical music CD I have that do support both lateral imaging, and depth to the recording.

The reconstruction filters are not always the issue, sometimes it is in the recording itself.

Imaging is profoundly recognized in the frequencies between 800 hz and 4khz - well within the bounds of CD's bandwidth. At 10khz and above which is CD's weakness, there is only harmonics, air, equipment and ambient noise of the recording space. Couple that with the fact that our hearing is less sensitive the higher you get in frequency(around 10khz and above) and at lower frequencies below 800 hz as well), and that supports the fact that imaging is not determined by high frequencies, or by low frequencies as well.

Also keep in mind these conclusions are only based on the authors experience. Yours may differ entirely.

Can anyone explain to me what is a Bluebook CD?

[StevenSurprenant]

I thought that you might enjoy this. I'm not taking sides because I don't know.


24/192 Music Downloads ...and why they make no sense:
24/192 Music Downloads are Very Silly Indeed