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In Reply to: RE: Thanks for the Clarity on HDCD - Charles post is a must read posted by Jeff Starr on June 13, 2017 at 18:45:09
>> I still see HDCD show up on Grateful Dead releases. My guess is they like the AD processor. <<
When it was first released the Pacific Microsonics A/D was dramatically better than the then-ubiquitous Sony - which is unsurprising as not many audiophiles have Sony preamps in their systems. IMO, the PM converters are still one of the top three or four in the world from the standpoint of sonic performance. Keith Johnson is an excellent designer and knows how to make a good sounding piece of equipment. (Think of Keith's other designs for Spectral Audio, for example.)
>> I know there are HDCD lists out there, do any of them show whether the processing was actually used? <<
It is true that there are many "HDCD lists" out on the interwebs. The problem is that the PM A/D converter will light up the "HDCD" light on *any* disc made using it - even if the mastering engineer turned all of the HDCD encoding features off. This is even true for all Reference Recording (Keith Johnson's label) releases after 2009 - they continued to use the PM A/D converter as it sounds very good, but with all the HDCD features turned off as there is almost no way to decode it any more.
The way the world was able to "peek behind the curtain" was when Foobar released their HDCD decoding add-on module. If you are curious just download Foobar for free and click on the link below for commands you can cut-and-paste that will display which HDCD features are actually engaged on any particular disc.
>> Were the PM chips in the DACs as good as the AD processors? <<
In the last millennium, only three high-end manufacturers had the knowledge to build custom digital filters - Wadia, Theta, and almost a decade later, dCS. All other manufacturers used off-the-shelf chips. Of those chips, the Pacific Microsonics combination digital filter/HDCD decoder had a good reputation for sonics for several years. Its digital filter was a conventional brickwall design, but had perhaps 1.5x or 2x more taps than other brands. The problem was that it did not support sample rates above 48kHz. So for about 5 years, the PMD-100 was the "go-to" digital filter chip for high-end manufacturers and even a couple of mid-fi brands - but *never* the mass market. The PMD-100 digital filter only cost about $5 more than a non-HDCD part, but also required the manufacturer to pony up a $5,000 licensing fee, which was later raised to $10,000.
Once true high-resolution became available in the form of DVD in 1997, high-end manufacturers had to choose between high-res and HDCD decoding. I think that maybe one or two products were made (briefly) with two digital filters in order to support both. Finally PM released the PMD-200, which was a pre-programmed Motorola DSP chip that could both decode HDCD and also provide digital filtering for high sample rates. As far as I can tell Motorola only made a sample batch of these parts. They showed up in the Sonic Frontiers DACs for a short time, and then Microsoft purchased HDCD lock, stock, and barrel. For several years in the early 2000s, Windows Media Player would decode HDCD, but I don't know that anybody cared or even really noticed.
By the time that HDCD had died, almost all DAC chips came with their own built-in digital filters. A few had selectable algorithms, but just as with IC op-amps, I don't think that there are people at large semiconductor manufacturing companies sitting around doing listening tests to make the very best sounding filters (or op-amps).
"If you want it done right, do it yourself" is an interesting saying and there are now at least a dozen high-end companies creating their own digital filters. It seems clear that the only reason to do this would be if you really believed it sounded better than what was available off-the-shelf in a DAC chip (although I'm sure there are cynics who will say it all sounds the same and is just an excuse to charge more).
As always, strictly my own opinions and not necessarily those of my employer or Mother Theresa.
Charles, do you happen to have Lucinda Williams "Car Wheels On A Gravel Road"? If so, could you check it to see if it is real or fake HDCD?
I tried doing a search, no luck on that CD, but I found a discussion on HDCD that was quite amusing. See the link, even back then Kal was correcting misinformation.
And for another good laugh, here is a link to Corey Greenberg's review of Howard's book. All from 2005.
> > Charles, do you happen to have Lucinda Williams "Car Wheels On A Gravel Road"? If so, could you check it to see if it is real or fake HDCD? < <
Sorry, I like that album a lot but never bought it. It was released in 1998, so if it lights up the HDCD light, chances are that it did use an HDCD feature that can be decoded but that is just a guess. The PM A/D converter is still one of the best sounding units ever made. Any mastering engineer that cared enough to purchase and use it was clearly dedicated to sound quality. Right off the bat those are two good signs - a great A/D converter and a mastering engineer who cares about sound quality.
As noted in the previous post LLE was not meaningful for popular music. As to whether PE was used would be just a guess without running the ripped file through Foobar. The operator's manual states:
Listening to both undecoded as well as decoded 16-bit playback is important, since HDCD
amplitude encoding effects such as Peak Extension limiting are more audible undecoded.
Limited Dynamic Range Pop or Rock
The best method to record highly compressed, limited dynamic range material depends
greatly on the results that are desired with undecoded playback.
Using Peak Extension allows very high average recording levels without "clipping" or gen-
erating "overs". This approach can be used to get the "hottest" possible sound (almost no
dynamics) during undecoded playback for air play, with decoding restoring normal dynam-
ics for home listening.
However, because Peak Extension limiting has an "easy over" curve that begins to affect
the signal at - 3 dBfs, it usually shouldn't be used with highly compressed source material
that will almost always be in the limiting curve, unless a highly limited or distorted sound
is desired during undecoded playback.
Typically, Peak Extension recordings do not have the "crunch" or "edge" produced by hard
clipping that is sometimes desired for certain types of rock material.
To get a hard "crunch" without any "easy over" limiting, turn Peak Extend off and adjust
DSPGAIN to a level just below full scale, usually - 0.1 dB. The digital input signal level can
then be adjusted using an external device such as a 24-bit editing workstation. This allows
as much clipping as desired without generating any "overs". To eliminate the need for an
external gain adjusting device, the Model Two can be put into a dual output mode with
digital output 2 set to HDCD_24, and digital output 1 set to HDCD_16, and offset -0.1 dB
relative to output 2 using OUT1OFS in the Levels Menu (see page 36). DSPGAIN can then
be adjusted to provide "crunch" on digital output 1 without generating any "overs". Digital
output 2 may then "over", but isn't used.
When a "dry" or "punchy" low level sound is desired with limited dynamic range material
that has little ambient information, Low Level Extension can be turned off.
That gives a "peek behind the curtains" as to the job of the mastering engineer. Clearly they are looking to create a "sound", not necessarily a direct transfer of the microphone signals to the disc.
I read your link to CG's review of Howard Ferstler's book. Pretty funny stuff! And have to admit that as a teenager in the '70s also had a Watts "Dust-Bug"... :-)
I still own the Watts Dust Bug, but haven't used it in 40 years. I wonder if it a collectable?
Around the days of the Watts I and a few friends tried the original Discwasher, and found it to create static. So, for many years I used a 3" Staticmaster, it had a horsehair brush and a strip of polonium. I still use the brush, but the polonium strip is outdated. Also use the AQ record brush.
You're probably right about Lucinda's CD actually using the HDCD settings. That album was recorded, scrapped, recorded again, and then she spent a lot of time adding and removing overdubs. I read that she was obsessed with getting it just right. All the effort paid off as she won Grammys, and lots of critical acclaim. I have found all of her albums to be well recorded. With the "Blessed" deluxe release the included second CD are the demos recorded in her kitchen on a portable Zoom recorder. And, they are surprisingly very listenable.
I've always admired your designs, but I live in Milwaukee, and I have never been aware of a dealer who sold them. So, I have never had an opportunity to hear any of your designs, particularly the amps would have been of interest. I was joking over at PS Audio that with the feedback on the latest firmware update, they should get the bronze busts ready for the Audio Hall Of Fame. I think there would be a place for you, if one existed.
I think everyone appreciates your contributions here.
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