Hybrid SACD/DVD (Part 1 of 3)

By Stefan Schreiber

The present situation

The current situation is well-known and unsatisfactory: the simultaneous market-introduction of two competing standards for high-resolution audio and surround-sound (DVD-Audio and SACD) is leading to big problems in the audio industry - and additionally, to frustration for audiophiles and "consumers" who are, in some cases, unable to reproduce on their audio-players a disc available for the competing standard.

As even DVD-Video is apt to distribute audio-recordings (and, of course, music-video), it could be said that there do exist three potential "CD successor" formats at the same time.

While the SACD standard allows a hybrid disc-form containing a CD-layer compatible with CD-players, DVD-Audio discs are often mastered as DVD-AudioV, containing audio recordings for normal DVD-players (Video), often in stereo (for example, PCM-96kHz), or in compressed surround-formats (Dolby Digital, DTS). Of course, DVD-AudioV discs can include music-video and further "extras".

As a "general" solution for the ongoing format-war between SACD and DVD-formats, it is often demanded that all new and advanced audio reproducers were "hybrid players", supporting both formats. These hybrid players should support the "DSD" (kind of high-resolution bitstream) modulation of SACD, and PCM in all quality levels of DVD-Audio (up to 192kHz, 24Bit). Although this sounds very convincing, it won't happen, in my opinion.

It is quite possible to equip hybrid players with chips supporting both formats, and also to design combined DACs supporting both DSD- and PCM-modulations. However, good reproducers will need different analogue paths after the conversions. The price of audio reproducers is mainly a consequence of good analogue components and DACs, not of ICs supporting two or three formats "digitally".

Some of the announcements made by Chinese manufacturers about the possibility to offer DVD-players with DVD-Audio- and SACD-support, for maybe $100, have to be considered from a critical point of view. The problem is not to support a format "digitally" and to reproduce it "somehow"; you have to do it well, especially in the case of audio. Otherwise, you wouldn't have to replace the "Compact Disc" at all, which already can sound quite well, but certainly not "perfect forever".

It is difficult to design a DVD-player with "good" audio-quality. It is needed experience and know-how for this task. Up to now, hybrid SACD/DVD players are usually better for ONE of the two formats, for example, because they convert DSD to PCM (up to 192kH) and vice-versa. This conversion isn't completely "without loss", and will result in "PCM with less dynamic bandwidth", or in "DSD with less temporal resolution".

It is revealing that hardly any hybrid SACD/DVD-Audio player can be considered to be a CD-player of "reference-class", which, considering sometimes high prices, is quite amazing, because you can very well "upsample" PCM in 44.1kHz/16Bit both to PCM in 96kHz (or 192kHz) AND to DSD, all in the digital domain. Expensive CD-players are quite often doing exactly this...

The current (and maybe future) low market-share of such hybrid players has very understandable reasons. The DVD-player market is extremely price-competitive. If a DVD-player is also a hybrid DVD-A/SACD player, it would be too costly and in a too high price-category for most customers. Audiophiles would consider buying such hybrid players, but they will be normally too expensive to be competitive in the mass-market. A DVD-player supporting both formats won't be a best-selling model, for price-reasons. Today, and probably also in future, obviously not every DVD-player is even supporting only ONE of the two high-resolution formats.