HD Audio FAQ
Since the first multi-channel audio format up to today’s standards, like DTS-HD Master, questions have been piling up, as it is well known that the technology is not as easy to understand as the good old stereo reproduction. For this reason, HiFi-Online.net offers you here the ten most frequently asked questions and answers about the high-resolution, digital sound formats.
1. What Multi-Channel Sound Formats Actually Exist?
In addition to the already somewhat older Super Audio CDs (SACDs), there are DVD-Audio (DVD-A) and DVDs based on DTS formats. Furthermore, multi-channel music recordings in Dolby Digital formats, such as Dolby True-HD, are already established on the market and deliver the corresponding high-resolution sound to the high-resolution images of the Blu-Ray.
2. What Is The SACD All About?
The SACD is a music recording and playback system jointly developed by Sony and Philips as a potential successor to the CD. SACDs operate at a sampling rate of 2.8224 MHz, 64 times that of a CD, as well as a frequency range of 100 kHz and a dynamic range of 120 dB. One advantage over the CD is that it has 6 times the storage capacity, which means that more music fits on one „disc“. If one plays SACDs on normal CD players, one has the sound only in conventional CD quality. To bypass the existing copy protection, you need an appropriate, certified SACD player.
3. What’s The Deal With DVD-A?
A DVD-A is a modification of the actual DVD and for this reason can also contain still images and video sequences. But if that were the case, the DVD-A would only provide a bandwidth of 6.144 MB/s for sound information, which would then make it a conventional film DVD again. However, since this is a music-only DVD and there is no film material, the bandwidth for audio information increases to 9.8 MB/s! This music can then be played back as 5.1 sound via the CD-compatible, two-channel PCM format as well as via a lossless MLP (Meridian Lossless Packaging) format specially developed by Dolby. Furthermore, the DVD-A offers a sampling frequency of 96 kHz as well as a 256-fold higher quantization, which specifies how many different digital values an analog signal converts. But just as with the SACD, a special DVD-A player is necessary here.
4. What Do I Need To Play SACDs Or DVD-A?
First and foremost the already mentioned player. This should offer an integrated decoder for the MLP and SACD format, which forwards the channels individually and analog to a receiver, which must have a 5.1 input. If it is only a stereo receiver, a conventional stereo signal is reproduced – and that is not the point! More expensive devices offer here a completely digital interface for the undistorted transmission of signals – but this must be encrypted and certified by the licensors!
5. What Are The Advantages And Disadvantages Of Using DTS Music DVDs?
The big advantage of these discs is the high compatibility with home theater systems. Almost every AV receiver and DVD player has an integrated DTS decoder – so you can play the disc immediately! The disadvantage, however, is that the playback is multichannel, but no higher quality than MLP and SACD!
6. What’s With The Analog Signal Transfer?
The reason for this crutch was the music industry’s concern about the perfect digital copy of an illegal origin. However, after some time there was a fully digital solution: i.Link! i.Link is an interface developed by Apple, also known as Firewire! Furthermore there is a so called proprietary connection, which transfers the unaltered digital signal completely unencrypted to the receiver! Besides the signal problem, the analog solution is also annoying because of the double work in programming the internal decoder to the speaker configuration. With digital transmission, only the AV receiver has to take care of this.
7. What Is The Perfect Speaker Setup For Multi-Channel Playback?
For multi-channel sound according to the SACD standard, all five speakers of a home theater system should be set up in a circle around the listening position and aimed directly at the listener. The subwoofer, on the other hand, can be placed largely anywhere, since the human ear cannot locate the low frequencies.
8. Doesn’t That Contradict The Correct Dolby Digital Placement?
It is quite possible! Especially the surround speakers are placed in different positions. For this reason, some receiver manufacturers offer to buy a second pair of surround speakers, the so-called B-surrounds.
9. Are Dipole Surround Speakers Actually Suitable For Multi-Channel Reproduction?
In most cases they are not. If there is the possibility to switch them to direct radiator operation, however, this is possible. Otherwise, a second pair of speakers must be purchased just for music operation.
10. Is Bi-wiring Suitable For Frequent Music Listening?
Bi-Wiring is well suited. Unlike film sound, where many sounds are constantly superimposed, the ear breaks down the frequency ranges much more clearly when listening to music in stereo mode. The signal distortions caused by the low frequency range via inductive effects in the cable can therefore be perceived more distinctly. Music often also distinguishes the men from the boys when it comes to the quality of the speakers!