How to get the best sound from your home theater ?

                          How to get the best sound from your home theater

How to make the sound effect of the home theater the best? Recently, a friend asked me, why is the effect of the newly purchased home theater system expensive? This is not the first time someone has asked a similar question. The effect of a set of home theater—especially the sound effect is not only related to the configuration of the system, but also the settings and adjustments in use have a great impact on the sound effect of the entire system. Improper setting and adjustment will not only fail to give full play to the good performance of the equipment and make people feel that the effect is mediocre, but what's more, the sound effect will be poor or the sound cannot be produced normally. How to reasonably match it into a home theater, how to use and adjust it to get the best sound effect?

System composition and equipment selection

Generally speaking, a home theater system consists of four major parts: audio and video playback equipment (signal source), AV amplifier, speaker system (speaker box) and large-screen TV or monitor. This article focuses on the first three parts related to the sound effect of the home theater system, especially the purchase, use and adjustment of AV amplifiers, which is also where ordinary consumers are prone to problems.

1. General principles of equipment selection

The core of the home theater system is the surround sound decoder, which can be built into the signal source device or AV amplifier, or it can be independent. For the convenience of connection and use, the family usually chooses a built-in signal source (such as a laser disc player) or an AV power amplifier, but if it is not necessary for equipment configuration, generally do not choose a built-in signal source decoder but a built-in AV power amplifier. The decoder, because the former cannot compare with the latter in terms of the convenience of line connection and performance.

When purchasing equipment, it is necessary to take into account the investment proportion of the entire home theater. The general point of view is that in a home theater, the audio and video equipment affects the sound quality as follows: speakers account for 50%, AV amplifiers account for 30%, and signal sources account for 20%. This cannot be used as a standard, but it can be used as a reference.

2. Selection of AV amplifier

(1) Choose brand-name products AV amplifiers are an important part of the home theater system, and you should try to choose products with high technical indicators and excellent performance. When purchasing, try to go to a reputable merchant and choose a well-known brand product.

(2) Determine the type of built-in decoder AC-3 has begun to be widely used with the recognition of the world film industry, and its software DVD discs have gradually matured and will become the mainstream of the market. Buy an AV amplifier with a built-in AC-3 decoder It is the need to follow the trend. But DTS is a surround sound system with more advantages than AC-3 to some extent, and the number of software is increasing. Therefore, it is a more ideal choice to purchase an AV amplifier with built-in AC-3 and DTS dual decoders.

(3) It is very important to choose the appropriate output power. The rated output power of the AV amplifier should be determined according to the driving power required for the actual use of the speaker. Usually, the output power of the AV amplifier should be 1.5~2.0 of the rated power of the speaker used in the system. times. If the output power is too high, it will cause unnecessary waste; if the output power is too small, there will be a situation of small horses and large carts, so that the speakers cannot get enough driving power, and the entire audio system cannot play the best sound effect. .

How to determine the required output power when choosing an AV amplifier? The output power of the power amplifier should be determined according to the size of the listening environment, sound absorption conditions and the sensitivity of the speakers used. The output power required in actual use is often much smaller than the theoretical calculation value. If the volume control knob of the power amplifier only needs to be rotated to 1/3 of the maximum volume during use, the volume reproduced by the speaker can meet the actual listening requirements. If it is needed, it means that its output power can meet the requirements of use, and the selection is more appropriate.

The function and adjustment of AV amplifier

In order to facilitate heat dissipation, the heat dissipation holes on the amplifier should be kept unobstructed, and should not overlap with other audio and video settings used in the home theater system; for multi-channel AV amplifiers with decoders, the use and adjustment are more complicated. When using, if The system cannot work normally, not because there is a problem with the matching of the system hardware, but because of the improper use and adjustment of the system, the problems mostly occur in the following aspects:

1. Correctly connect all components

There are many input and output terminals of the AV amplifier. When wiring with various signal equipment and speaker systems, it is necessary to ensure that all connections of each audio component and video component are correct, such as L (left) to L (left), R (right) to R (Right), "+" vs. "+", "-" vs. "-". Some components need to be connected with different connection methods and the terminal names are also different, such as COAXIAL (coaxial), OPTICAL (optical), S-VIDEO (S video), VIDEO (video), AUDIO (audio), etc. The terminals are different from IN (input) and OUT (output). It is necessary to ensure the correct connection between different types, input and output terminals, which is the prerequisite for the normal operation of the system.

2. Correctly select and set the working mode

(1) Input mode (INPUT MODE) selection The amplifier generally has a variety of input modes to choose from, such as AUTO (automatic), ANALOG (analog), DTS (digital movie interplay system), etc., depending on the type of program source to be played Only by choosing the input mode correctly can the system perform at its best. The preferred order of signal selection is: digital signal encoded with Dolby Digital or DTS → ordinary digital signal (PCM) → analog signal (ANALOG); when the input mode is set to AUTO (automatic) position, the input from the signal source Signals are selected in the following order of priority: COAXAL (coaxial) terminal → OPTICAL (optical) terminal → ANALOG (analog) terminal. Note: Some modes are mutually restrictive. Improper selection will cause the system not to work normally. Be sure to read the instruction manual carefully before using the amplifier.

(2) Selection of sound effect mode To use the EFFECT (sound effect) switch correctly. When the system is playing standard stereo sound sources such as CD records or dual-channel tapes, it is best to turn off the sound effect speakers (center and rear) to obtain the original sound field effect; Correctly choose the sound effect processing program: PROLOGIC, AC-3, DTS or various CINEMA DSP (cinema digital sound effect processor), whether the choice is appropriate, whether it is appropriate or not, is crucial to whether a good surround sound effect can be obtained important.

3. Setup and adjustment of speaker system

When the home theater system works in the surround sound mode, the quality of the surround sound field is not only related to the quality and performance of the speaker system itself, but also whether it is correctly set and adjusted is also an important factor that cannot be ignored.

(1) Set the working mode of the speaker. According to the size and presence of the speaker (speaker) of the system configuration, correctly set the center speaker (CENTER SP), rear speaker (REAR SP), main speaker (MAIN SP) and subwoofer output (BASS OUT) to make it in proper working condition. There are generally three working modes of the center speaker (CENTER MODE): normal (NORMAL) mode - suitable for the case where the center speaker is small in size and moderate in performance; wide (WIDE) mode - suitable for the center speaker and The frequency band and carrying power of the front main speaker are equivalent; Phantom (PHANTOM) mode - choose this mode when the system is not equipped with a center speaker. In the instructions of some AV amplifiers, the above three modes are often referred to as SML (small speaker), LRG (large speaker), and NONE (no speaker), but the selection principle is the same as above. Similarly, the main speaker and the rear speaker should also choose the appropriate working mode according to their size and performance, and the subwoofer channel also has two different modes to choose from depending on whether a subwoofer is connected or not. In addition, there are two working modes: 3CH (three-channel mode) - the rear surround speakers are omitted, and only the front and center speakers are reserved: OFF mode - the center and surround channels are turned off, no output, suitable for Plays standard stereo sources such as CDs.

(2) Speaker volume balance adjustment (output level adjustment) Adjusting the output level of each channel to keep the power of each speaker balanced is a key step to obtain the best overall sound effect. Use the test audio signal to adjust: put the total volume control knob at 1/3, set the BASS (bass), TREBLE (treble) and BALANCE (left and right volume balance) control knobs to "0" position, connect the test signal ( Press the "TEST" key), and you will hear a test audio signal (like random noise) from each speaker for about 2 seconds in the following order: left main speaker → center speaker → right main speaker → right rear speaker → left rear Set the speakers, adjust the output level of each channel to match each other, that is, the loudness of the sound from each speaker is balanced and consistent. AV amplifiers without test signals can be adjusted using feature films with surround sound, and the basic process is the same as above. Most of the genuine multi-channel encoded DVD discs sold on the market now have test audio signals attached.

(3) Adjust the loudness To achieve a satisfactory sense of presence when listening to surround sound, you must have sufficient loudness, that is, a loudness that is equivalent to the real sound. The method to adjust the loudness is: first adjust the level matching of each channel, select a movie with only dialogue, adjust the main level (MAINLVL) of the system, so that the dialogue loudness can reach an appropriate level when the overall volume control knob is at a lower position, Amplifiers without a master level control can only control loudness with the master volume knob. Of course, to achieve a certain loudness, there are also certain requirements for the power amplifier configuration (the power of each channel). In order to achieve a better theater effect, you might as well turn up the volume a little bit.

4. Delay time and dynamic range adjustment

When using processors such as Dolby Pro Logic, Dolby Digital, or DTS decoders, you can adjust the delay time between the main sound and the sound effect sound according to your own preferences, that is, adjust the start time of the main speaker and the distance between the sound effect sound of the rear speaker. The time difference between the start times to get the sound field effect that suits you.

In short, to make the sound of the home theater system "beautiful", it is necessary to match the system equipment reasonably, and to use and adjust it correctly. To some extent, the correct operation and adjustment of various equipment in the system is more important than equipment selection. No matter how good the equipment is, if it is not used properly, its sound effect will not be as good as a set of ordinary equipment.