Compact Disc Formats
Compact Disc Formats Preamble
1. In response to customer inquiries, I have in this paper attempted to briefly explain the various CD formats available in the FIM catalog.
2. I must point out, however, that this is not a technical paper, but rather some explanation in layman’s language to questions frequently asked by customers. In addition, I admit to occasional subjective views which may not reflect the entirety of technical specifications on certain issues. This unavoidable subjectivity results from the fact that, in most cases, the proprietors of the formats concerned keep private the details and specifications of their technologies.
What does “CD format” mean?
3. There are two aspects to understand about “CD formats”: the disc and the software. Storage Medium: The Disc
4. The CD is a circular polycarbonate disc of 4ľ” diameter, used to store content in digital format, playable by a CD player. The micro-thin metal film plated on the top surface of the disc is the medium which actually stores the music data. This film is usually aluminum; some CDs are filmed with gold or silver, resulting in better reflectivity and lower distortion rates—as well as a higher manufacturing cost.
5. In recent years, some disc replication manufacturers, in their endeavor to offer superior products, have introduced new types of polycarbonate materials, such as SHM (Super High Material), and real glass, both introduced by Memory Tech, Japan. Other manufacturers apply coatings such as the RCC (Resonance Control Coating) introduced by FIM. These innovations allow the carrier disc to provide improvements in sound quality. It is not, however, the objective of this paper to comment on these new materials or coatings.
6. Music content is stored in one of three formats:
(i) Regular CD: In the music industry, this is called the “Redbook” standard. The Redbook standard is a technical specification, with an operation frequency of 16-bit / 44.1 kHz, using PCM as the operation mode. This specification was introduced by Philips in the early 80s.
(ii) SACD—Super Audio CD: The operation frequency of this format is 1-bit / 2.8224 MHz, using DSD (Direct Stream Digital) technology. It provides higher density and a larger capacity than the Redbook standard; however, it can only be played on an SACD player. To facilitate the playing of the music content by a regular CD player, space is allocated for music data encoded at the Redbook standard to be stored on the same disc as well. This dual version is called Hybrid SACD. SACD has the capacity of storing complex multi-channel music data for five or more channel reproduction.
(iii) DVD/A: This is, in fact, a PCM based DVD technology, which is playable on a DVD player for audio applications. The advantage is that the operation frequency is much higher, 24-bit / 96 kHz, and thus is capable of high resolution sound quality. Normal CD or SACD players cannot offer DVD/A playback. A variety of factors have rendered this format unpopular, and it is not widely available due to lack of support in the industry.
Recording and Mastering: The Software Recording
7. There are two recording formats: analog and digital.
8. Analog recording is an earlier format, dominant prior to the advent of digital. Analog is still regarded as one of the best-sounding formats, and is preferred by engineers at some audiophile labels. Despite its inherently cumbersome operation, audiophiles love analog’s musicality and superiority of definition. The notation “A” is generally used in the production data of the liner notes of a CD to indicate analog recording methods have been used.
9. Nowadays, most recordings are created digitally from 24-bit / 96 kHz, 24-bit / 192 kHz, or even higher resolution frequencies such as DXD, in 24-bit / 352.8 kHz, or Pure Analog, in 32-bit / 192 kHz. A digital recording is represented by a “D” notation.
10. Some CD jackets feature a small logo, such as AAD, which means the recording is analog; the mastering is similarly analog; but the replication is digital. If the logo is ADD, it means that the recording is analog, mastering is digital, and replication is digital. If it is DDD, the entire production process is digital. Mastering
11. The recorded material, whether in analog or digital format, must be mastered so that corrections, editing, sound equalization, normalization, and other technical adjustments can be instituted prior to the manufacture of a glass master stamper for CD replication. This process is called Mastering.
12. Regardless of whether the original recording is analog or digital, mastering is mostly accomplished digitally. Occasionally, discerning engineers choose to master through the analog format, but replication is, inevitably, done in the digital format (i.e., the CD).
13. In recent years, many new mastering formats have been introduced, with results varying from the negligible to the phenomenal. Audiophiles can become perplexed about mastering when they read advertisements, reviews, and reports in magazines and other media. In many cases, due to a lack of clear explanation or misleading advertising, customers misunderstand or misinterpret new mastering formats, and believe that a special player is required for a certain format. This is not true. The simple rule is that, with the exception of SACD, all available CDs—regardless of mastering format—still comply with the Redbook standard, and are playable on any CD player.
14. A mastering engineer may choose a particular format to do his job, using equipment capable of higher resolution than the Redbook criteria. However, at the end of the process, he must convert or down-sample the mastered material to the Redbook specification, so that CD replication can be conducted. Hence, all kinds of CDs (excepting, again, SACD) are manufactured at the Redbook standard as a final product, though their sound characteristics may vary due to different mastering formats, equipment, and more importantly, the skill and the reference sound of a particular mastering engineer and producer.
15. Now, let us talk about the various mastering formats seen in the industry:
(i) K2 Interface Encoding System: Developed by two JVC engineers in early 1987. This format can be regarded as the first audiophile attempt at better A to D conversion. It is now considered out-dated, and has been replaced by other formats.
(ii) HDCD (High Definition Compatible Digital): Strictly speaking, this is not a mastering format, but a very good filtering circuitry developed by Pacific Microsonics, USA, in the early 1990s. HDCD minimizes digital noise and lowers the jitter rate. A CD player equipped with this circuitry is identified by a blue light on the front panel.
(iii) XRCD (Extended Resolution CD): In 1993, the K2 Team at JVC succeeded in creating 20-bit super encoding with the use of a special 20-bit A/D converter. In 1999, JVC launched its first XRCD products, using in the mastering process a device capable of a higher sampling rate than the Redbook standard.
(iv) SACD/DSD: In 2000, Philips/Sony launched the new DSD (Direct Stream Digital) format for recording and mastering encoding at a 1-bit / 2.8224 MHz operational frequency, based on DSD, a departure from the PCM-based Redbook standard. DSD has higher resolution and capacity, and is playable on an SACD player. In a hybrid version, the Redbook portion on the same Hybrid SACD is playable with a CD player.
(v) XRCD 24: In 2002, JVC’s XRCD technology further matured to become a format capable of encoding 24-bit in the mastering process and using a rubidium clocking device, thereby achieving sonority to rival the SACD, while retaining the PCM domain, and thus being playable on all CD players. FIM had the honor to debut this format at the 2002 CES exposition.
(vi) K2 HD: The K2 Team at JVC did not rest on its laurels. In 2004, another major breakthrough was achieved with the encoding not only of 24 bits, but also a 100 kHz sampling rate, into the Redbook confines. After the testing of this technology in the Japanese domestic market by JVC, FIM officially launched this superior K2 HD mastering format in August 2007 at the Hong Kong High End Show, and then again later at the January 2008 CES.
(vii) DXD: The full name of this new format is Digital eXtreme Definition. It offers higher resolution capability than any other existing mastering or recording formats, operating at a 24-bit / 352 kHz sampling rate—three times the data rate of SACD. DXD was initially developed for Merging’s Pyramix DSD workstation, which processes all PCM data at 32 bit. Again, FIM had the privilege to debut this superlative format on an international basis, in March 2009.
Which is the Best Technology?
16. Given the array of recording, encoding, and mastering formats briefly outlined above, readers are sure to ask which one is the best.
17. My answer is that there is no such thing; we can only compare and make our own choices. My experience tells me the end result always hinges on the skill, the musical reference, and the knowledge of a particular engineer or producer. I often use photography as an analogy to explain this perhaps unsatisfying answer.
18. Imagine that two photographers compose a photograph of the same object. One of these photographers is rather new to his craft, but is equipped with the best available gear. The other artist is a seasoned and experienced photographer who uses his 40-year-old analog camera. The results will be vastly different: the latter may capture the essence and the soul of the object, while the former may convey other attributes with an unmatched precision. Certainly, if we could achieve the best of both worlds, the photograph would exhibit an outstanding level of excellence.
19. In the audio arena, musicality, tonality, dynamic contrast, and definition are abstract qualities which may not be achieved as a matter of course simply by using the latest and most-advanced machines or technologies; results are frequently even more dependent on the skill and artistry of the production team. Advanced technology and equipment are important tools. However, the end result still relies on the sculptors of the sound—our imaginary photographers—in this case, the artistry of the production team.
What is the Latest Technology?
20. Digital technology advances so rapidly that, in a matter of a few months, a new format may emerge as a more-advanced tool for engineers and producers in their pursuit of better sound.
21. By April or May 2010, another new format in audio software will be introduced by FIM: “Pure Analog – 32-bit 192 kHz Captured!” This introduction will mark another major step towards the realization of the presence of live music. The first title in FIM’s Pure Analog series will be “What’s New?” by Linda Ronstadt.
22. In the hardware camp, the USB credit card format will be introduced as well, a format which is capable of offering any high resolution sampling rates that are available currently or in the future. FIM is planning to introduce this “credit card” format in a couple of months.
23. More information on these two new-comers will be made available soon.
24. Lastly, don’t be surprised if Blu-ray technology for audio software and hardware soon makes inroads into the audiophile community. Too, it is probable that music servers and audio credit cards will become mainstream, perhaps even overtaking major market share from CDs.
Prepared by Winston Ma, President, First Impression Music, Inc. (All rights reserved) March 16, 2010