The truth behind HDCD audio

What is HDCD and would it work at Octave Records?

[@TheJediJoker]

HDCD ("High Definition Compatible Digital," *not* "High Definition Compact Disc") was developed by Pacific Microsonics, who later sold the tech to Microsoft, who have since abandoned it. HDCD-encoded Compact Discs are still being produced, however, notably by the Grateful Dead for their live archive series. HDCDs have two optional features: 1) Peak Extend (PE), which increases headroom by about 6dB on playback, and 2) Low Level Extension (LLE), which enhances dynamic resolution at the lowest levels on encoding only. If neither of these features are employed, the CD is effectively standard Redbook, just with the HDCD "flag" encoded into the least significant bit. Therefore, such a CD will still be "decoded" by an HDCD decoder, with the only effect being a ~6dB drop in playback volume. As LLE has no effect on playback, the only feature of real importance is PE. If PE is employed, this means that during encoding, peaks approaching 0dBFS (digital maximum) will trigger a compressor to keep them at -6dBFS and below. This is then level-shifted back up so that -6dBFS is now at 0dBFS again. When decoded, the level is shifted back down 6dB and the compressed signal is re-expanded, restoring the lost dynamic range. Without an HDCD decoder, however, this lost dynamic range cannot be recovered. Not good! While I can't speak to Reference Recordings specifically, the sad reality is that most recordings-especially remastered analog pop/rock/jazz albums-simply don't possess enough inherent dynamic range to warrant the use of PE. If such a recording is encoded with PE, it only serves to create an artificially compressed version that is heard when played back without HDCD decoding. It is likely this additional compression was not intended, approved, or even heard by the mastering engineer. It would be far better to simply encode in standard Redbook, so that any player will reproduce the master as created and intended. Today, if you want greater than 16 bits of dynamic range, go for lossless 24-bit or DSD downloads, streaming, DVD-Audio/Video, audio Blu-ray, and SACD. So, why do so many HDCD-encoded CDs sound so good? Paul pretty much nailed it: because the recordings (or remasters) are good. Some of this may be down to the analog-to-digital and digital-to-digital converters of the Pacific Microsonics Model One and Model Two converters, which are used to encode HDCDs. These units have been praised and sought after by audio professionals for their sonic characteristics, and all HDCDs will have been through their circuitry. Surely, the Models One and Two have been surpassed in technical performance by now, but they may still possess a subjective edge over more modern converters.

[@Unicorn-ST]

Great info. Microsoft didn't do anything with HDCD but they included the technology in Windows Media Player with one you can still play HDCD discs. When you play an HDCD disc, the logo HDCD appears. What I am not sure is what happens when you rip an HDCD disc with Windows Media Player, it would be great if it creates a flac file with all the HDCD info, but I am not sure if it does it. What is clear, as I mentioned in other comment, is that usually the HDCD are very well recorded... Therefore they sound great even when are played as regular CD.

[@lukpac]

LLRE is absolutely an encode/decode process and has an effect on playback. If used and not decoded, quiet sections will be louder than they should be. This is usually most noticeable on fade outs, especially with older recordings with tape hiss. The level (and tape hiss) will increase in steps as the track fades out.

[@TheJediJoker]

Yeah, @@lukpac, I confused LL(R)E with the transient filter, which is not an encode/decode feature.

[@chipsnmydip]

A friend of mine has a PM Model 2, and while I can definitely hear jitter and noise in it, the sound is very beefy and rich. Partly due to an enormous power supply that is almost the same size as the converter itself, and the R2R converter design which is really coherent in the bass and midrange (kind of like a primitive MSB-type sound). Some mastering engineers still use them. I've definitely heard cleaner and more detailed analog to digital converters, but the HDCDs just sound very big and rich.

[@martinbishop2966]

HDCD recordings are really good, I have a number of these recordings and they beat SACD and DSD hands down!.😃

[@Unicorn-ST]

When I had to changed my CD player, I looked for one multi player that was able to play HDCD because I have some HDCD , mainly from Dire Straits and Mark Knopfler. It’s important to mention that an HDCD disc can be play in an standard CD player, but is when you have a player with the HDCD license when you take benefit from this technology. But finally I don’t notice any noticiable advantage. My thoughts about this is that people that recorded with HDCD, also we’re people that did very good recordings… and once again, this is the real difference. The recording is far more important than the resolution or the format.

[@Venus_Isle]

Used to love it back in the day, in the rare instances when the HDCD light got activated on my Rotel RCD 971 CD player...🙂

[@chiefputty]

Paul, as an owner of hundreds of HDCDs, I would love to see you guys put this decoding in your DirectStream DAC (should be able to with a software update?). I am using your PerfectWave transport, but to get the full benefit from my dics, I have to go with a Berkeley DAC. Food for thought.

[@tee-jaythestereo-bargainph2120]

PS auduo would have to buy the rights for the decoding '

[@dennismanning6684]

Hi Chief, I'm not sure the DAC does any HDCD decoding, maybe. It's kinda involved to A-B test but on my Aria HP stand alone rig I tried OPPO 83, HDCD - ON, and OFF, SE analogue output... less compressed sound with On (increase the vol to match with "OFF")....BUT, the best sound either on or off was feeding a Pontus II DAC via I2s/HDMI in Oversample mode. Very much better air, separation, impact, etc. there was less volume shift also. The Pontus II has the 3rd gen FPGA upgrade which I think fixed an issue where if input dropped below 0db...which is exactly what HDCD encoding does, the Pontus has been shown to clip such peaks (Golden Sound) previously. Haven't seen new measurements but it sounds great with all sources.

[@krellman7]

The HDCD was actually introduced in 1995. The company was actually Pacific Microsonics and the founders were Keith Johnson and Michael Pflaumer. Some high end manufacturers actually incorporated active circuitry to support this format. I remember at the time I purchased a Krell KPS 20i which was quite pricey back in the day. Krell offered an upgrade to support HDCD. It was called the “Delta 9” upgrade which included a board replacement and also included a faceplate change that was labeled HDCD and a light would light up indicating if the HDCD circuit was active. If I am not mistaken, this was originally labeled “pre-emphasis”. Was there a noticeable difference? Yes, there was. To sum up, it was not Reference Recordings that was originally involved in the making of HDCD, however; they did produce recordings that were HDCD encoded. I hope helps clarify. One final thought to share…..there were over 5000 titles produced with HDCS encoding.

[@bikdav]

Question to Paul: In other words, it’s not the playback format, but how it was recorded in the first place?

[@martineyles]

The available dynamic range on the CD format is pretty big. The main reason for CDs not sounding amazing is the way people make recordings rather than the format itself.

[@pablohrrg8677]

No matter how good the system, quality is limited by mastering.

[@chipsnmydip]

Others have said it, but a big sound of HDCD is the Pacific Microsonics converter they used. The company basically gave them away for free to promote the format, but in 1990s dollars they would have been worth around 18k. I still greatly prefer DSD, given the right ADC and DAC, but with HDCD it's always the same converter so you kind of know what you are getting.

[@TWEAKER01]

Additionally, 20-24 bit recordings properly dithered to 16 bit achieves that effective 18 bit dynamic range, by not only avoiding the low level truncation distortion but by preserving correlated audio signal *within* the dither noise. This preserves the otherwise lost depth and detail of the higher depth source.

[@j.t.cooper2963]

I still have my Denon HDCD capable CD player from 2000. I wish i had more CD's with HDCD encoding because I can definitely hear the difference on the CD's that have that capability.

[@davidclarke6658]

I agree with you. There is a German label who made audiophile DSD SACD compilation dual layer disks (can't remember the name off hand) and even the CD layer of the disks blows most other CD's I have away in terms of sound quality. Wish all CD's could sound that good.

[@sidesup8286]

You can count on there always being money considerations considerationsbeing behind things. Car noise is why music is compressed. Most people's music listening is in cars, and given that fact at their disposal, you can count on the music industry to tailor things toward that. If they made irecordings with higher dynamic range, people would adjust the volume control in their their vehicles downward, so they don't get blasted out of there..Of course that would mean that average loudness levels in the music would be less loud, and more importantly to them, commercials would be less loud and commercials would be competing with road noise and other extraneous noises inside vehicles.

[@Slammy555]

I prefer the 2015 remaster to the Van Halen HDCDs, I think it's a good example of how mix is the most important aspect. What I like about HDCD is how, even compressed, they still register as HDCD.

[@phrtao]

I always associate HDCD with my Grateful Dead CDs (including several 10+ disc box sets). As you said it was used by people who were trying to get the best out the recordings. In the case of the Grateful Dead I think the Plangent remastering system used to digitise the original source tapes made the biggest difference.

[@michaelgriffiths4539]

Hi Paul I’ve found out using J river you can record at 192 or 96 bit rate on to DVD and play them back on certain blue ray players or 4K players such as Oppo or Panasonic what thoughts do you have on that

[@michaelgriffiths4539]

And way hasn’t anybody put discs out at this bit rate on DVD it’s a simple process from a hi res source

[@mondoenterprises6710]

Almost all my cd/hdcds, Petty, Joni, Neil, GD, Keb Mo, Slow down, Lucinda W Car Wheels, Beach boys, et al. sound better thru my hdcd capable player. People often fail to mention that when the cds were sold you got hdcd tech for free. You could just play the cd as a cd and be fine. You might have to buy a new cd or dvd player that had the hdcd decode tech to play it and pay some more there if you wanted to access the hdcd sound. You don't get that many top tier artists to sign on unless you have something good to offer it would seem to me. I'd like to a/b the hdcd tech against some of today's top tier dacs and hear the difference.

[@birgerolovsson5203]

My absolute best sounding CD is an HDCD, all my 286 SACDs included.

[@volpedo2000]

Which one?

[@birgerolovsson5203]

@@volpedo2000 Mike Oldfield - Amarok Fantastic compared to the original. I have them both.

[@manitoublack]

I'm with Paul. Put in the hard yards in the studio and follow best practice in the mastering and they'll be little need for the extra dynamic range of a HDCD. The extra fedelity of DSD or 24/96 is a different story however.

[@volpedo2000]

@@birgerolovsson5203 my best sounding CD (although sounding might not be the right term) is Kodo - Heartbeat Drummers of Japan. Insane what they squeezed in 16bits

[@birgerolovsson5203]

@@volpedo2000 Thanks for the tip.

[@kautkascitadaks]

Hdcd is not a format but a way to get 20 bits of resolution out of 16bit files(by doing clever math and dither. What you have there is a 20bit file that is inferior to a real 24bit flac. Its a nice thing that was necessary at the time to get better sound, not anymore unless you have no hires dad or player.

[@jctai100]

HDCD gave license to recording/mastering technicians to do a better job although not needed.

[@D1N02]

I have a CD player that can play it so I got a hdcd especially to test if it worked ;)

[@markschotgerrits283]

Do you need to have a capable cd player to "decode" the HDCD's? In the past I saw the HDCD logo on many DENON cd players. And it also lit up a symbol on the display when playing those discs

[@birgerolovsson5203]

Yes, not all can play HDCD. My Oppo BDP-95 can but my newer Oppo UDP-205 can't.

[@bergennorway]

You can rip it at computer to get the HDCD format, to FLAC or similar. DB Poweramp can rip it, I did that when I ripped my CD’s to FLAC and stored them on a harddrive. That way I still have the HDCD, and can play it with any source that can play FLAC!

[@birgerolovsson5203]

@@bergennorway Yes, I know and I've done that also but I ripped my +2500 CDs to wav instead with CD Ripper in dBpoweramp. Great program.

[@ArturdeSousaRocha]

The irony is that the only HDCDs I have are loudness war remasters of Roxy Music albums. What a waste of technology.

[@thexfile.]

Japan used Pre-emphasis not HDCD.

[@davidlong1786]

What snake oil crap 🤣

[@60zeller]

Ahhh you liked your own comment. That’s so cute

[@davidlong1786]

@@60zeller No some one else with intelligence did that. Next time try not to insert foot into mouth.

[@mafi211]

HDCD 📀 👍👍👍👍

[@BuckNaked2k]

"...sold the tech to Microsoft, who have since abandoned it." 🙄