What is the difference between Dolby Digital and DTS?
What is the difference between Dolby Digital and DTS? In the next few paragraphs I will try to explain to you in the easiest way possible.
First of all, Dolby Digital and DTS are both 5.1 formats and can be mono, 2 channel stereo, 4 channels or how many channels they want. Both are a 20 bit format, which if you think of our audio CDs they are 16 bit. So the more bits you have the better the sound quality.
Now, here is the biggest difference of them all. Lets think of ratios first. With Dolby Digital, you have around a 12:1 ratio, where the DTS track is around a 2:1 ratio. Now that is a big difference just in ratios. Basically what that means is that Dolby Digital does take up a lot less space on the DVDs and of course DTS takes up more space on the disc. If you look at it at the tech term Dolby Digital uses a 384 kilobits per second (kps) or sometimes they use 448 kps which is considered a high quality Dolby Digital bit rate. Now with DTS, they have been using 1536 kps. Well, DTS has been running into many obstacles in the last few years and went back into the labs and decided that they could lower the bit rate to 768kps. This helps ease up the space factor on the DVD disc. Don't panic even at 768kps the sound quality on the DTS disc is real close to the 1536kps. Which is a good thing cause now you can have both Dolby Digital 5.1 and DTS 5.1 audio on the same disc and you can choose which version you want to listen to and still have room left over for extra goodies. Therefore, if you ever wondered which titles have the DTS 768kps, it is the one with a Dolby 5.1 track and DTS 5.1 track. Of course, there are some instances like the Saving Private Ryan disc, where the DTS version where the sound is at 768kps and I can assure you that the sound quality blows away the Dolby Digital version.
Although they are both the same type of coding technology. In an audio signal, you have many sounds that are on top of each other. When you have sounds that are stack up like that you are not really hearing the whole signal. Cause certain sounds are masked out or canceled each other out, therefore you just do not hear them. Even if you do not hear the audio frequency, they are still taking up space. What DTS and Dolby Digital does is with their technology, they both take away the audio signal that you cannot hear and reduce the size of the audio signal, which gives you more room for different audio languages and commentaries on a DVD disc. How Dolby and DTS do this are two diffrent techniques and technologies, which I will not get into.
If you want the highest quality audio today, DTS is it. But, do not get me wrong; Dolby Digital is still a great format and still sounds very good. It is just not the best; DTS is just a little better.
Below I left some Q&A from the DTS web site.
The following series of questions and answers address the introduction of DTS-encoded DVDs.
1.What is DTS Digital Surround, and how does it compare to Dolby Digital?
DTS is an encode/decode process that delivers 5.1 channels of "master quality" audio on DVD. Each DTS encoded disc represents a sonic "clone" of the original film soundtrack.
Dolby Digital (DD) is a standard for 2-channel audio playback, and approx. 80% of the current DD titles already on the market, offer only stereo or mono soundtracks. At the same time, DD also can deliver a 5.1 channel soundtrack, and in 1/3 the "space" of a DTS bitstream by compressing the available data by a ratio of 12-to-1. This offers the studio the option to include three different languages, instead of a single "master quality" DTS soundtrack.
2.When comparing the two technologies, most consumers refer to 3 sonic advantages for DTS:
Subtle Nuances - Every individual sound effect is crystal clear, adding to the sonic realism of the soundtrack.
Dynamic Range - The loudest "bangs" have more depth, and the quietest passages are "noise-free".
Channel Separation - All 5.1 channels operate at full potential without sonic "bleeding" or "collapsing".
3.Does the high data rate used for DTS 5.1 soundtracks result in lower video quality or fewer "extras" on a DVD?
No. DTS takes up more space than a Dolby Digital soundtrack -- which is one reason it has higher fidelity - and (at 1.5 Mbit/s) exactly the same space as a PCM stereo soundtrack. This leaves plenty of room for high quality video, a commentary track, trailers and "making of" documentaries, etc. all on a single disc!
However, some DTS-encoded DVDs may be released with fewer (or different) extras than the non-DTS versions. This is simply the decision of the producer of the disc, and not usually the result of space limitations.
Please note: The Dances with Wolves 2-disc package is an exception that represents a special "collector's" version with the absolute highest video and audio data rates possible.
4.Why do some DTS tracks sound louder than the Dolby Digital version?
DTS soundtracks are delivered to the end user at exactly the overall level of the master, to preserve the full quality of the original.
Dolby Digital incorporates dialog normalization, which alters the decoded level of the soundtrack. The typical setting reduces level by 4 dB; other reduction levels are possible. In most decoders, this leads to a reduction in signal-to-noise and dynamic range.
Dolby Digital also provides a "stereo downmixing" feature as a substitute for a dedicated stereo mix. However, many production engineers have admitted that they often have to modify the original 5.1 mixes in order to attain acceptable stereo downmixes. Therefore, the 5.1 mix on many Dolby Digital DVDs may differ from the original master.
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