HDCD: an investigation

Could be, actually, Peak extension is by no means the only benefit claimed by the makers of HDCD.

 

That's not what PM (ad Microsoft) claimed -- see the wiki entry on ''High definition Compatible Discs' --eg. the Low Level Range Extend
feature. See also tps' post (#19 in this thread).

 

Are you doing these comparisons levelmatched and blind? There's a ~6dB difference between the two, for one thing! That alone will make them sound rather different.

 

I would advise against that until more definite information is available. I'm finding interesting threads about HDCD on several
forums, and some of the information is conflicting. One key bit would be knowing whether WMP's HDCD decode DSP does everything a
hardware HDCD chip would be expected to.

 

You make a valid point of course - however, I did take into account the level change (it is plain to hear).

My tests weren't scientifically rigourous but honestly the change wasn't subtle so I don't think it is too wreckless of me to go out on a limb and say the difference is there.

One rough method I used was basically just play each file as loud as is comfortable on the headphones to roughly level match - the differences were clear as day. In fact, at any playback level on either headphones or loudspeakers I could tell which file was which. Of course, a blind test would be better but I am satisfied enough to go about ripping the 20 or so HDCD discs I have in my collection and I wouldn't be bothering with that undertaking unless I was convinced there was something to be gained......

So, how about help with this batch process - anybody?......

 

Well, I am like a pig in $hit here

These decoded files are AWESOME!!

I've scrapped the idea of creating a batch file to do this and have done it manually (dosn't take long once you get the hang). I am enjoying the Pet Sounds Sessions box set more than ever

I always wanted an HDCD player to squeeze the supposed extra quality out. Finally I have got round to using this ripping method and was disappointed to discover that the waveforms looked identical but just reduced by 6dB. However, listening to the results has proven to me there is more to this HDCD business than meets the eye.

Interestingly, I have noticed that rather than my DAC just reporting these HDCD decoded wav files to be 17-bit it is actually reporting varying bit-depth anywhere from 17-bit to 20-bit throughout each song. This variation seems to be related to the volume - the louder the music the higher the bit-depth reported.....

Anyone else tried this on the Beach Boys discs yet or getting similar results with other HDCD discs?

 

I didn't see reference to this in the thread previously.. but have you tried comparisons from any of Steve's Audio Fidelity gold discs with HDCD?

 

I don't have any

 

Is that what "Convert to Album Images with Cuesheets or Chapters" does? I always wondered about that

For what it's worth, Rockbox will play 20-bit and 24-bit FLAC files (with or without cuesheet). I don't know if the hardware (Sansa e250) actually supports that bitrate, but the firmware does...

 

Question for SiriusB:

Even without change in DR, wouldn't increase in bit-depth be a good thing in a decoded hdcd?

Or in the case of some of us here - if we took the undecoded hdcd and re-encoded with dither like uv22?

This is where I'm a little fuzzy.

 

Speaking of Steve's HDCD discs, I was wondering if the Cal Tjader SACD's CD layer is encoded with HDCD. It doesn't light the HDCD indicator on my EAD DSP-7000 III DAC.

 

Wouldn't that answer the question??

 

Yeah I guess it would. It could also mean a pressing plant problem. Mine was bought from a regular store, but I have record club HDCD marked pressings that do not light the indicator. Perhaps an altered master?

 

There are discs labeled HDCD that really aren't.

 

My copy of Sara Evans' "No Place That Far" is marked HDCD and it does not decode as such on my DAC. The later release "Born To Fly", OTOH, is indeed HDCD.

The former is a BMG club release though...

 

I have a store bought copy of No Place That Far and the detector did the same thing. I tried my Columbia House copy of I Hope You Dance by Lee Ann Womack and that is indeed an HDCD.

 

For Take Five on the Time Out HDCD undecoded:
Left Right
Min Sample Value: -29684 -28856
Max Sample Value: 29683 29469
Peak Amplitude: -.86 dB -.92 dB
Possibly Clipped: 0 0
DC Offset: -.001 0
Minimum RMS Power: -87.73 dB -88.21 dB
Maximum RMS Power: -5.69 dB -8.72 dB
Average RMS Power: -18.8 dB -20.77 dB
Total RMS Power: -17.19 dB -19.4 dB
Actual Bit Depth: 16 Bits 16 Bits

Using RMS Window of 50 ms


Decoded:
Left Right
Min Sample Value: -16303.25 -13052
Max Sample Value: 16336.38 12268.5
Peak Amplitude: -6.05 dB -8 dB
Possibly Clipped: 0 0
DC Offset: 0 0
Minimum RMS Power: -97.35 dB -97.27 dB
Maximum RMS Power: -15.34 dB -17.16 dB
Average RMS Power: -26.05 dB -27.9 dB
Total RMS Power: -24.44 dB -26.52 dB
Actual Bit Depth: 20 Bits 20 Bits

Using RMS Window of 50 ms

 

Yep, that's it. It's the first time I've used it too.

Foobar (0.9) can play the captured .wav (wich it interprets as a 24-bit file) but so far can't play a flac made directly from it (which it interprets as a 20-bit file). This might be due to the wavex thing, or maybe foobar just can;t play 20-bit files, I haven't worked it out yet. The immediate workaround for me is to open the flac in Audition and resave it as a 24-bit flac.

 

Not really. People generally can't tell a 14 bit file from 16bit, much less 20 from 16.

Not sure what you're getting at...if you mean converting from 16 to 20 or 24, all you'd be doing is 'padding' the file.

 

It appears from what I've read that just using the 'HDCD' A/D converter (designed by Keith Johnson-- sold by Euphonix but now discontinued) adds a flag to the file that makes the HDCD light go on. A bit of advertising, in a way. Since that converter was supposed to be among best of class in its day, I don't blame them.

 

I meant the other way around - take the 20bit file and convert it to 16bits.

One thing that is missing from hdcd.exe is the proper choice of filter whose instructions could be encoded into the file.

 

I have a Steve Winwood CD...Junction Seven that says HDCD on the CD and Jewel case insert but when I put the CD in my player the HDCD indicator doesn't light up. That is the only one I found so far.

 

Neil Young's "Prairie Road" CD is an HDCD.

 

The HDCD indicator doesn't seem to light up anymore with Windows Media Player 11...

Too bad.

 

I'm glad I never upgraded from WMP 9. I hate when newer versions have less features. :thumbsdn: