Does HDCD make a noticeable difference?

Nope, the same as playing HDCDs on an HDCD-badged player...

 

Thanks testikoff for your answers. Maybe I should just compare both and trust my ears!

 

HDCD encodes 4 extra bits of info inside the least significant 16th bit - they're pseudo 20-bit recordings. With the extra dynamic range that affords (6dB worth) they do things like peak extend, which also has to be decoded to be of any use.

In the case of the Joni CDs, I think they sound great whether HDCD is properly decoded or not. dBPoweramp has the ability (maybe via a plugin) to partially-decode HDCD. I don't think it can take advantage of the peak extend, but it can decode the extra 4-bits of info, and save the resulting FLAC file (or whatever lossless format you choose) as a 24-bit file (with the extra 4 bits beyond the 20 being padding). According to Roger Nichols, increasing the bit-depth helps with the digital recording of bass, something I first noticed on the Mitchell HDCDs - I thought the bass seemed richer and more natural somehow (I had a Toshiba DVD player that decoded HDCD). At the time I just chalked it up to equalization, or maybe PM's superior A/D and D/A converters, but now I suspect the extra bits played a role.

Curiously, if you just play an HDCD disc in your computer using Windows Media Player, it can detect and decode HDCD, including all the features. That's because Microsoft bought Pacific Microsonics (and then promptly buried the technology -sad).

 

But it doesn't, really. All it does is shift the 16-bit window up or down slightly. Any particular sample will contain at most 16 bits of information. PE and LLRE then shift that sample up or down. It may be fair to say that it can offer up to 20 bits worth of dynamic range, but it isn't actually encoding 4 extra bits.

If PE and LLRE are not used, there is no extra information. Those features, and those features alone, are what produce the "extra 4 bits". The HDCD plugin will decode those features, but there won't be any better bass because of it.

When you perform a null test between decoded and non-decoded files, the result is mostly silence. The only information that's there is in very quiet portions of the program (due to LLRE) and peaks (due to PE).

 

Hmmmm. That makes sense.

LLRE causes that "stepped" quality in fadeout doesn't it, where the tape hiss suddenly gets louder during the fadeout on undecoded recordings?

 

Yes, exactly. As the level goes down, LLRE boosts the level in a series of steps. That process gets reversed during decoding, so you just hear the normal fade, but without decoding you can hear the steps.

 

Do you have an idea WHY Microsoft bought PM and the HDCD technology? Exactly what was it they wanted?

 

Sea Change has the HDCD magic bits, but doesn't make use of any of the HDCD features
HDCD: peak extend: none, transient filter: none, gain: none
It's effectively just a standard CD.

I prefer the MFSL CD version to the standard CD version by a large measure. I haven't heard the Blu-ray version or the HDTracks version.

 

They wanted the patents for how the hidden data bits are encoded. I suspect they saw it as something that could be of use as part of a DRM measure or technique. I don't know if they ever actually made use of it.

 

my "Two-Cents"; M$ was on a high buying up a lot of tech & wanting too expandED far beyond "Windows" windows in too media, sooooo at-the-time it made $en$e.
All too quickly tho, it was off too other new territories; HD-DVD & X-Box too name two.

i was hoping since the 800 LB gorilla was in the room w/HDCD; everyone would join in; didn't happen.
Butt, the HDCD filter got inbeddED in too M$ media, which at-the-time was one of the better digital filters out there.
So, a small win for audio.

 

Hopefully this will be helpful:

1/ the descriptions given above wrt "4 bits" and "window", if not incorrect, are perhaps unintentionally slightly misleading.

The amplitude processing options available to the mastering engineer are 1/ "Peak Extend" which is a precisely-reversible soft limiter that only kicks in on peaks, no signal impact below limiting onset except a fixed gain-scaling factor; and 2/ "Low Level" processing which is compression intended to raise low signal levels based against a certain threshold.

For playback decoding, peak unlimiting and low-level signal expansion, along with other HDCD functionality, are precisely controlled by signaling which "steals" the LSB of a 16-bit audio sample, on only something like 2% of audio samples, in order to insert control codes as part of dither. Some info in previous posts made here on SHF as well as on Head-Fi, such as this one. Read more in the Johnson/Pflaumer AES paper and Pacific Microsonics Model Two manual, links to those and other documents can be found here; see especially the HDCD Gain Scale Application Note for diagrams showing i.e. limiter curve and the impact of amplitude processing.

For general overview, excerpt summary info from the AES paper

The encoding process starts with a high resolution analog-to-digital (A-D) conversion of the analog input signal, typically yielding a digital signal at twice the final sampling frequency and a 24 bit word length. This over-sampled high resolution signal is analyzed in real time to determine which aspects of its sonic character will be most compromised by reduction to the standard PCM signal at any given time, and pairs of conjugate processes are chosen dynamically to minimize the sonic damage on playback reproduction. Areas of sonic compromise which the system addresses include dynamic range, amplitude resolution, timbre, and anomalies normally caused by a brick wall anti- alias filter with a cutoff frequency near the top of the audio band.

The over-sampled signal, delayed long enough to allow the analysis and process choice, is decimated to the final sampling rate using one of several filters chosen based on program content. The resulting signal has its dynamic range reduced using a combination of reversible soft peak limiting for infrequent peaks, and average level based compression for low level signals. The signal then has high frequency dither added and is quantized to the final wordlength.

All parameters and processing choices made during the encoding phase are inserted into the data stream as pseudo-random noise encrypted control signals inserted into the least significant bit of the audio data as part of the dither, on an as-needed basis. The encrypted control signal allows the decoder to apply accurately timed conjugate processes during playback without using media format dependent sub-codes. The decoder restores the limited peaks, accurately expands the compressed low levels, and applies a conjugate interpolation filter to match the anti-alias filter of the encoder.

The system remains compatible because the corrections are only applied for signal extremes, increasing the average modulation with minimal sonic alteration of undecoded playback. Since the encoding parameters and exact timing are conveyed in the control channel, the recording engineer can select a combination of process parameters suited to the program material, and the decoder accurately follows, providing the correct conjugate reconstruction.​

2/ best available info indicates that MS appears to have acquired the HDCD intellectual property primarily in order to utilize the hidden signaling capability (i.e. the inserted command packets) as something akin to a watermark used in protection of software distributions. HDCD decoding in winamp was a happy byproduct; don't know if current version of winamp still decodes?

edit -- small addition for clarity

 

HDCD is a royal pain the butt for Mac users who don't and won't run Windows on it with no freeware for Mac that will decode it.

 

Why bother with HDCD at all?

If you want hi-resolution digital, go get hi-resolution files instead.

 

I'm not sure what's misleading about calling PE and LLRE a "sliding window". Because that's what they do: adjust the gain of particular samples.

 

It was a question. I asked because I'm curious.

 

You "go with HDCD" because it's what's available as a consumer. I have about 20-30 titles...few to none are available as high Rez digital. Unless you mean why from an engineering standpoint, as a consumer you don't get to choose. I know some classic rock stuff has been mastered both ways--it will ultimately come down to the master quality itself.

That said....my two year old Oppo is the only HDCD I've ever owned. I've briefly had some on trial...and they were always nicer than redbook, but not worth buying a player for a dead format. The Oppo decoding is absolutely gorgeous. The unmarked original CD release of Kevin Gilbert's Shaming Of the True and the era of Nashville recordings that use it...as well as Elvis Costello's Painted From Memory-It's like hearing them again for the first time...it's certainly nicer.

I even bought one last year--the new Amy grant is HDCD...and since the Oppo allows you to turn off the decoding, I can directly compare--sounds much better decoded. It may just be something with the transient filters and the downing of the volume a few DB, but HDCD on the Oppo 105 is stunning.

I've been meaning to mess with decoding to linear 24bit files...but, honestly--it's got nothing to do with virtual bit depth...everything to do with whatever transient filtering...and th downing of the peak volume. Some are more dramatic than others...but, it makes a lot of Nashville records of the 96-2002 era much nicer...actually makes the releases just north of that hard to hear--because the gradual loudness increase is kind of undone on the HDCDs and goes right to the 2003 of like DR6.

 

Thank you for the detailed, clear, and logical explanation.

 

At the time HDCD came out there really wasn't much in the way of high res audio out there. DVD-Audio and SACD were out on the horizon, but required at the time much more expensive players and discs. HDCD uses conventional CDs and is perfectly compatible with standard CD players. The D/A converters required for HDCD were relatively cheap to manufacture.

In a way, given what a flop they were in the market, I almost wish DVD-A and SACD had never happened, and the market just standardized on HDCD. I think it would have been an improvement until Blu-ray Audio and higher-res downloads came along. On the other hand, when DVD-A and SACD came out the labels were still awash in money and spent quite a bit having stuff re-transferred and remastered, and sometimes remixed for multichannel. Many of the high-res downloads available today probably date from those remasters, so perhaps we're lucky DVD-A and SACD came out when they did, even if they flopped...

 

Nashville used it a LOT in the 90s.

It was an attempt to deliver closer to the 20-24bit 48khz masters being made on straight CD. It was dead by 2001 when SACD and DVDA showed up to replace CD. I'm told by some local guys they still use it for the 100khz conversion, which makes sense to me--because I KNOW capturing at 96khz makes a better 44.1 track than capturing at 44. So, if it captured at 100khz in 1996, and dynamically shaped the decimation filter based on transient content, no doubt it would produce a nicer 44.1 master than some Apogee 20bit comverter at the time.

Funny this comes up...my wife handed me a stack of her CDs she wanted to trade in...to see if I wanted any of them...and Inpopped in a Losa Leob from 96'ish and it turned out it was an HDCD. Sounded purty--Bob Clearmountain mix....HDCD master....before the world of CDs got stupid loud...it's sad to compare it to new DR6 pop recordings of today.

 

The Mo Fi Sea Change remains one of my disappointing discs of recent years. I'm always interested to understand what people hear on this disc that they like in comparison the the original disc. Why do you think it's better?

You need to compensate for the volume difference between them as the Mofi is a fair bit quieter but it really sounds a muted/colourless disc in comparison to the HDCD to me-if you put the HDCD against the Blu Ray you hear on the Blu Ray an even more colourful vibrant version of the record.

I've stated a few times on here I loathe the fact Paper Tiger is a different version on the Mo Fi disc....drives me nuts.

 

Sounds like you prefer a more compressed bright sound. No problem with that, but most audiophiles on this forum like the non-compressed smoother sound of the MFSL.

 

I'm not sure that's a fair comment at all. I don't think the Blu Ray or the HDCD versions are bright at all-it's a great recording.

In relative terms the MF version is more muted and a lot may depend on your system in terms of how things are presenting themselves as well-with all due respect I don't think I have a system that lends itself to anything other than a good standard of neutral replay and a pretty revealing one at that.

I don't think the MF presents even a SACD style presentation where you get that smoother effect which invariably on the higher level of system you have tends to make you just sit back and enjoy the music-no I hear the MF presenting quite a colourless and less vibrant one.

All I want when I listen to music is a feeling that my system is revealing everything on the original recording and is giving me a presentation I enjoy-when you start to A/B a certain recording you get into more complex areas-I've tied myself in knots before and probably will again but on Sea Change I have listened to the different versions a lot.

One of the remarkable things to me is that despite the purist approach and a label that says Original Master Recording the MF Sea Change gives us a completely different and disorientating second track. It's a major flaw for me.

 

Here is the dynamic range of the HDCD:

DR Peak RMS Duration Track
--------------------------------------------------------------------------------
DR8 -0.10 dB -10.20 dB 4:37 01-The Golden Age
DR6 -0.10 dB -8.17 dB 4:36 02-Paper Tiger
DR9 -0.10 dB -10.29 dB 4:49 03-Guess I'm Doing Fine
DR6 -0.10 dB -8.03 dB 5:38 04-Lonesome Tears
DR7 -0.10 dB -9.90 dB 3:47 05-Lost Cause
DR8 0.00 dB -10.33 dB 5:03 06-End Of The Day
DR8 -0.10 dB -10.54 dB 3:06 07-It's All In Your Mind
DR7 -0.10 dB -8.89 dB 5:15 08-Round The Bend
DR7 -0.10 dB -9.61 dB 2:59 09-Already Dead
DR7 -0.10 dB -8.60 dB 4:44 10-Sunday Sun
DR6 -0.10 dB -7.92 dB 4:27 11-Little One
DR10 -0.10 dB -12.04 dB 3:24 12-Side Of The Road

vs. the MFSL

DR Peak RMS Duration Track
--------------------------------------------------------------------------------
DR13 -0.34 dB -15.63 dB 4:47 01-The Golden Age
DR11 -0.25 dB -14.29 dB 4:42 02-Paper Tiger
DR13 -0.22 dB -15.38 dB 4:58 03-Guess I'm Doing Fine
DR11 -0.53 dB -14.22 dB 5:40 04-Lonesome Tears
DR11 0.00 dB -13.86 dB 3:52 05-Lost Cause
DR13 -0.15 dB -16.52 dB 5:08 06-End Of The Day
DR12 -0.07 dB -14.80 dB 3:10 07-It's All In Your Mind
DR12 -0.20 dB -14.56 dB 5:25 08-Round The Bend
DR12 -0.17 dB -14.99 dB 3:20 09-Already Dead
DR10 -0.17 dB -13.25 dB 4:47 10-Sunday Sun
DR11 -0.20 dB -13.78 dB 4:30 11-Little One
DR11 -0.13 dB -14.21 dB 3:31 12-Side Of The Road
DR12 -0.16 dB -13.85 dB 3:23 13-Ship In The Bottle

The MFSL sounds much more natural and easy on the ears to me. I know some are not bothered by compression and might also prefer Bob Ludwig's eq choices vs. Rob Loverde.

 

I do headphone listening. I've never actually listened to Sea Change on speakers. Only on headphones. I don't know how much of my explanation and preference will translate to speaker listening.

With the MFSL the sound is holographic. Surrounding my head. There's layers. There's depth with the center of the image filled in and a clear sense of depth. It's like putting my head inside a circular sound field. Vocals are in front and in the center. Instruments are in layers behind existing in their own spaces not crowding the vocals in the front. This is the kind of listening experience you can get with headphones when the recording is good and the gear is good.

With the CD the sound is flat like a textured oil painting. The sound exists as blobs around my left ear and right ear. The middle doesn't fill in with the sense of depth. It's like listening to a flat painting. Vocals are in the center but all the instruments are crowding forward and not giving the vocals their own space. All the instruments crowd amongst themselves without having their own space and own layer.

The MFSL CD and the standard CD versions do put you in different moods or feelings. The MFSL puts me in a very ambient relaxed mood like sitting in an overstuffed comfy chair just being immersed in space and sound. The standard CD gives more energy and a less relaxed and immersed feeling while listening. The two versions will create different interpretations and analysis of the album. I don't know which experience more closely represents what Beck wants to deliver. I do know which experience I prefer and which I find much more interesting to listen to.