Do you know the four common surround sound processing systems in home theaters?

Do you know the four common surround sound processing systems in home theaters?

1. SURROUND decoding virtual surround sound technology and chip

Qsurround is currently a relatively new set of sound processing systems that can perform sound field processing on ordinary discs (stereo) and simulate Dolby surround sound effects, which is suitable for all sound sources.

2. Dolby AC-3 system

The Chinese full name of Dolby AC-3 is Dolby surround AC-3, and the English name is Dolby surround coding-3, which means Dolby surround audio coding (type 3). Dolby AC-3 is a fully digital audio signal processing system that requires 6 completely independent channels, namely full-band left, center, right, left surround, and right surround, plus a subwoofer channel. This system is also called 5.1 channel or 3/2 type, which has 3 front channels and 2 independent surround channels. The Dolby AC-3 decoder decodes the original six-channel signals. The frequency responses of the left, center, right, left surround, and right surround channels are all in the full frequency band, that is, 20HZ-20KHZ. Each is counted as one channel, and only the overweight The frequency response of the bass is 30HZ-120HZ, counted as 0.1 channels, and the sum of the six channels is 5.1 channels.

Dolby AC-3 performance features

1). Pure digital sound effects, wider dynamic range, higher signal-to-noise ratio, and sufficient surround output power.

2). Equipped with truly independent ultra-low frequency information output, you can achieve extraordinary and shocking sub-bass effects.

3)． Each channel is fully digital and independent of each other. Each channel carries different signals independently of each other, and is a 100% digital signal.

4)． After sound time calibration, the sound effect is extremely ideal. The surround sound effect is not only that the front, rear, left, and right sound sources are clearly positioned, but also the upper and lower sound fields are clearly distinguishable.

3. Home THX system

THX is a movie surround sound standard launched by Lucasfilm in the United States. In recent years, it has been transplanted to home theaters. It is also called Home THX. The THX system is an optimized standard based on Dolby Surround Sound. It adopts 5.1 channels, namely L, C, R, SL, SR, super bass SW channel, because the SW channel is derived from other 5 independent channels, and only plays back low-frequency signals below 120HZ.

4. DTS system

Dolby Surround has further improved the sound quality and developed into sound systems such as THX and AC-3, because AC-3 is still not the most complete. In August 1996, the American DTS company officially launched the DTS digital surround sound system. DTS processing is based on AC-3 and is upgraded again. It uses built-in chips to assemble signals, but at the same time transfers the information recorded in each channel to other unseen channels. In the fully stored sound channel, the amount of information is greatly enhanced, and the timbre performance is more stable and perfect.

The DTS system, like Dolby AC-3, also uses a 5.1-channel format, but can pass up to 8.1 channels. In the multi-channel processing method, each channel signal needs to undergo filtering, frequency division, spectrum analysis, re-quantization and other processes before being sent to the "common bit group" for further processing. There is no need for matrix processing in each channel signal. There is no need to use "coupling" techniques between different channels. This processing method helps to improve the purity of the sound, so that all audio signals after decoding can be reproduced without distortion, enhancing the sense of space, depth, and presence.

The audio digital compression ratio of the DTS system is smaller than that of Dolby AC-3. It is almost lossless compression. Its frequency response width is equivalent to the CD standard. In this way, the replay sound of the DTS system is slightly better than that of Dolby AC-3. It is also very suitable for recording large-scale Multi-channel live concerts and HI-FI music with relatively high sound requirements.