More Than 16-bits CDs

Yesterday, I laid out the case for avoiding XRCDs…especially if you’re considering paying $35 for one. Heck, I charge $35 for a Blu-ray disc with HD-Video; three mixes and loads of extras! I heard from a couple folks in appreciation and one person who said that I was being mean. Information is power. I actually laud the folks at JVC for doing their very best to deliver everything that the Redbook standard can deliver. I think they are over priced and over hyped but they do deliver everything that was on the source recording. I meant it when I said that the dynamic range of virtually all commercial music doesn’t come close to using the full 16-bits available. Most rock n’roll and pop music would fail miserably if there were huge dynamic swings. The radio station wouldn’t know what to with a dynamic recording.

Contrary to the claim from JVC that they deliver “eXtended Resolution” on their CDs, there is a special technique that can add 4 additional bits of dynamic range to the venerable CD. The method is called HDCD and it was developed by Reference Recordings Keith Johnson and Michael Pflaumer. Normally, I would rant against saying that a CD could exhibit HD (High Definition) specifications and I would quibble that an HDCD is not really HD by my definition. Still the format as developed by Pacific Microsonics did advance the potential fidelity of compact discs before any of the real HD format showed up.

How did HDCD eclipse the 16-bit barrier of the Redbook spec? Well, they encoded some special codes in the LSB (Least Significant Bits) that when read by a custom decoding chip would translate to potentially better fidelity. They messed around with dithering, Peak Extend, which is a reversible soft limiter and Low Level Range Extend, which is a reversible gain on low-level signals. These techniques do actually accomplish what they set out to do but the discs had to be processed or encoded with HDCD AND the CD players had to be able to decode the process. While the discs did remain compatible with standard non-HDCD players, there was some compromise to the noise levels.

Pacific Microsonics introduced HDCD (which were identified with their logo) in 1995 and as many as 5000 titles were processed with it. In 2000, Microsoft purchased the assets of the company and included the patented technology in their Windows Media software players. The format still exists but only as a legacy decoder in hybrid machines like the Oppo line of players.

If you recall, 2000 was the year that DVD-Audio and SACD were introduced. Audio enthusiasts looking for better fidelity were ready to move to 24-bits and higher sampling rates. In fact, I remember having that very conversation with Michael Pflaumer at a trade show…I think it was an AES convention in San Francisco years ago. As I was about to launch my own record label and recognized that CDs would be superseded by high definition PCM at 96 kHz/24-bits, I wanted to know why anyone would want a CD with a custom format added to it for a few extra bits when there would be new software and hardware that advanced way beyond the CD specs. Michael remained steadfast to the notion that HDCDs would have a place in the marketplace. Perhaps he was right.

I think they had the right idea. HDCD was a REAL improvement to CDs! Unfortunately it didn’t happen ten years earlier when it might have had an impact.


Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called iTrax.com. A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

5 thoughts on “More Than 16-bits CDs

  • Frank Lattermann

    Good post,

    I own personally around 40 CD’s with HDCD encoding and I always felt that they sounded better than most of the ‘regular’ CD’s. Most of them are Reference Recordings, which sounded better than most CD’s anyways. I also own around 10 XRCD’s and I was always wondering what the fuss was about, as I couldn’t really hear any improvements over regular CD’s. Thx for the clarification. BTW, I got them for a good price, not $ 35 a piece.

  • Hi Frank, with what player do you play your HDCD’s? I use an old Oppo 980. Silly thing is, I *think* the decoder is in the DAC, so I have to play HDCD’s through the analog output if I want proper decoding.

  • Frank Lattermann

    Hi Grant,

    I USED to play my CD’s with a Parasound Drive CD 2000 and Decoder 2000, which had also HDCD capability. Since I upgraded to HTPC (HomeTheaterPC) setup, my player (foobar 2000) plays HDCD with a plug in. The rest of the setup is 6 channel 192/24bit capable and it sounds wonderful.

  • Phil Olenick

    I have both a Denon 2910 DVD player and an Oppo BDP-93 Blu-ray player that can decode HDCDs. The Oppo is, in addition, a network player that can pull files off my UPnP/DLNA server on my PC – but if it gets a WAV or FLAC rip of an HDCD disk it doesn’t recognize it as being HDCD-encoded.

    There is, however, a free DOS utility floating around the web on hobbyist bulletin-boards. Put a WAV rip of an HDCD into a folder and run that utility, pointing it at that folder in a DOS-like command window, and it decodes each track, writing it out as a 24-bit WAV file (zero padded, since it’s really only 20-bit) with a string added to the title to distinguish it from the original.

    Those can then be pulled over the network – either as is or converted to FLAC to cut the needed space and transmission bandwidth in half (and also allow the addition of tags) – and played back by the Oppo (or any network streamer capable of playing a 24-bit file, even if it can’t otherwise play HDCDs) in their full 20-bit glory.

    • Phil Olenick

      If there’s still controversy about whether FLAC is really lossless, consider this: I bought Denny Zeitlin and David Grisman’s recent duet album, New River, as a FLAC download of the 44/16 CD from HDtracks. I burned a standard audio CD to play in my car using Winamp, and discovered when I played it in my Oppo that it was an HDCD, even though there was no mention of that fact in the multipage album insert that came along as a PDF with the FLAC download.

      The decoder program I just described extracted the 20-bit version, which I turned back into a FLAC to tag it with track titles, the artist’s names, and the album cover. Played over the network, it sounds beautiful – and the difference from the undecoded version streamed is clear: the piano and mandolin (it’s a duet album) can be heard as separate layers much more clearly in the decoded version. From FLAC to WAV to decoded WAV and back to FLAC – and it sounds pristine and clear. FLAC truly is lossless.


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