About Dolby, All you want to know


All kinds of publicity about Dolby Atmos are endless, and various concepts and logos have confused consumers. So how to distinguish these concepts? How to build a home theater system? For further sorting out, I leave this article here. It will be continuously updated and improved in the future.

1. Dolby Concept:​

Dolby Vision; Dolby Atmos; Dolby Audio; Dolby Digital Plus;

Common audio track formats for Dolby Atmos are FLAC, AAC, AC3. Dolby Digital Plus audio format DDP/DD5.1/AC3/EAC3.

2. Dolby Atmos has two audio formats: Dolby TrueHD and Dolby Digital Plus.​

Dolby TrueHD: Dolby Digital Plus audio format, the bit rate is 640Kb, the content is compressed to a sampling rate of 48kHz, and supports 5.1 channels or 7.1 channels with optimized sound quality; generally used for online video streaming and cable broadcasting, it is compressed online format.

Dolby Digital Plus: Dolby TrueHD lossless audio format, the highest resolution and high quality Dolby Atmos. HDMI connection is required to fully restore 5.1 channel or 7.1 channel, the sampling rate is 96kHz, and the bit rate is between 3Mb-18Mb. Generally used in high-definition disc players, A/V receivers, home theater packages, sound bars and other equipment.

3. About the number of channels of audio equipment Stereo system:​

Generally, there are 3 channels of center + left and right channels. There are only 2 channels of left and right speakers. Some manufacturers will also achieve 5-channel through simulation, but not true panoramic sound. For example, some TVs set the speakers around the screen, or deliberately reflect the 2 channels to the wall and transmit them from the sky, thereby simulating 2 sky channels to promote the support of Dolby Surround.

Dolby Surround Sound System: Above 3-5 channels, basic physical surround effects can be achieved. Some manufacturers will also add virtual channels to take effect similar to Dolby Atmos.

Dolby Atmos: Support 7.1 channels to become Dolby Atmos. Center + front, back, left and right + two sky down.
Last edited:



What is the difference between Dolby 5.1 and 5.1.2, 7.1 and 7.1.2?​

Take 7.1.2 as the example: 7 represents the total number of sound positions 1 represents the subwoofer, generally, only one is needed without any position, the largest and highest one in the echo wall system. 2 is the last data that represents the number of sky sounds. We often see various combinations of manufacturers in post-simulation, such as 9.1.2, 11.1.4, etc., which are all based on this evolution.