As a music lover, and especially as a reviewer for MusicWeb International, I am confronted with a number of different types of optical discs. CDs and DVDs are, of course, the most common, and have been around for a long time. But in the past couple of years, Blu-Ray discs have come into the market, and they are especially desirable for recordings of classical music concerts or operas.
But even CDs offer a variety of formats. In addition to regular CDs – which follow the “Red Book” standard – there are SACDs, and these come in two types: either in stereo or with multi-channel sound, and they are at a much higher resolution than standard CDs. While most SACDs sold today are hybrid – featuring a CD layer and an SACD layer – there are still some that are not. In addition to offering more channels or higher resolution, SACDs also offer much greater capacity, potentially providing a playing time that exceeds CDs.
Another format is the HDCD standard, which is not widely used. However, I have dozens of HDCD discs, because one of my favorite rock bands, Grateful Dead, issues all their recordings in this format. HDCD claims to offer better resolution than standard CDs, yet these discs are compatible with standard CD players.
There is one last form of “hybrid” disc: the DVD-A, or DVD-audio disc. This is a DVD, just like one used for a movie, but where there is little or no video. (There are generally only menus and/or still images.) The advantage of using DVD-A is longer playing time – up to several hours – and higher resolution files in stereo or multi-track.
When it comes to DVDs and Blu-Ray discs, there are also audio formats that need to be decoded, such as Dolby TrueHD and DTS-HD Master Audio.
So, with all these formats of optical discs, it can be very useful to have a device that can play them all. This is the case with the Cambridge Audio 651BD, which handles all of the above formats, including 3D Blu-Ray discs.