Dolby Digital VS PCM – What is the Best Audio Setting for Home Theater
Most people tend to confuse Dolby digital with PCM, while others do not know which to choose and why they should. Although most people hear different things when it involves sounds, they would still like to know which is better for the purpose they require.
This article would serve as a guide to help you serve the mystery about Dolby digital vs PCM and which is better for your digital or streaming purposes.
What is Dolby Digital?
This is a digital audio encoding system used for DVDs, Blu-ray discs and sometimes for streaming content or Television Broadcast.
It has the capacity to provide effective transfer for audio signals that may be made up of one or more channels that can be decoded by using a home theater receiver or AV processor with a Dolby Digital decoder and distributed to one or multiple speakers.
Dolby digital is modernized forms of coding audio digitally that makes it possible to safe keep and pass across high-quality digital sounds more efficiently than before. Dolby digital was developed by Dolby laboratories.
It was named Dolby stereo digital originally but was changed in 1994. Dolby digital was first used to provide digital sound in cinemas from 35mm film prints. Now it is also used other ways which include HDTV broadcast DVDs and Blu-ray Discs and various game consoles.
Dolby Digital is Also Recognized as; DD, DD 5.1 and AC3.
Most home theatre receivers have Dolby digital decoders built in them, also all DVD and Blu-ray disc players have the capacity to pass Dolby digital signals to other receivers which are properly equipped for decoding.
Although Dolby digital is recognized as a 5.1 channel surround system, the term Dolby Digital itself refers to the digital encoding of the audio signals and no the amount of channels it has. Basically Dolby digital can also be
- Monophonic; means it can be represented by one or multiple speakers although both speakers produce the same sound.
- 2-channel; also represented by two speakers, one placed on the left and on the right front of the listening position
- 4-channels; this has 4 speakers. Two are placed on the left and right front of the listen area, and the other two are placed on the left and right behind the listening area.
- 5-channels; is made up of five speakers which include; left, right, cente,left and right surround and a sub woofer. This is the most commonly used channel.
Versions of Dolby Digital
- Dolby Digital EX
6.1 Channels – this has a third surround channel that is located directly behind the listener, it is made up of six speakers which include left, left surround, right surround, right, centerback, and a subwoofer. A home theatre with a Dolby Digital Ex decoder is needed for this.
- Dolby Digital Plus
7.1 Channels; this is in a format that is high definition and supports as much as 8-channels of surround decoding. It also contains the basic Dolby digital 5.1 bitstream which is compatible with a standard receiver. This is one of the audio formats designed and used by the Blu-ray disc format.
Other versions of Dolby Digital includes; Dolby Digital Surround EX, Dolby digital Live, Dolby Digital plus and Dolby digital True HD.
What is Pulse-code modulation (PCM)
Versions of Dolby Digital
Pulse-code modulation (PCM) is a way of representing sampled analog signals digitally. It is a standard type of digital audio in computers, digital telephony, compact disks and various other digital audio applications. The amplitude of the analog signal is regularly sampled at uniform timing in a PCM stream. Each sample is quantized to the closest value within the range of digital steps.
What is Linear Pulse-Code Modulation (LPCM)
Linear pulse-code modulation (LPCM) is a precise type of PCM where the quantization levels are uniform linearly; this is different from PCM encodings where quantization levels differ as a function of amplitude. Although PCM is more recognized and used for describing data encoded as LPCM.
A PCM stream contains two basic properties that help determine the fidelity of the stream to the original analog signal. They include;
- The sampling rate which is the total number of times a sample is taken per second
- Bit depth; this determines the number of digital values that can possibly be utilized in representing each sample
Dolby Digital vs. Pulse-code Modulation (PCM)
Pulse-code modulation (PCM) should not be confused with a Dolby digital even though it is also digital in nature. The Dolby digital is compressed and it is encoded digitally in a manner different from PCM.
Although Dolby digital encoded signals can be encoded into PCM signals and sent through HDMI to an increasing number of home theatre for more processing and amplification which is common in majority of the HD-DVD players and Blu-ray applications.
There are arguments about PCM being better than Dolby digital because PCM is uncompressed and brings out the best output whereas Dolby digital is compressed and data is dropped so space could be saved. This drop in data reduces all round quality which most people are against.
DOLBY DIGITAL vs PCM Linear
Linear PCM is uncompressed and unmodified from the source it comes from, it is a straight digital sound that is being played and can be interpreted by basically and digital system.
Dolby digital is a method of processing; this basically means that the signal of the sound is being changed in a lot of ways so as to create wider or larger sounds. Because it utilizes its own language to encode signals which are modified, only TVs and receivers that specifically support Dolby digital can play a signal that has been encoded in that way. Because of this, you may not be able to enjoy Dolby encoded sounds on all digital setups.
Basically people have different preferences, but the advantage linear PCM has over Dolby Digital is the fact that you can play and enjoy it on all digital devices while you can’t do the same with Dolby digital.
Although, Dolby digital has various enhancements that Linear PCM lacks, which for some people could be a big deal.