How to improve the sound effect of multimedia conference system

Author: 　 From: 　 DateTime: 2022-06-15　 Hits: 5189　 【Font: T  T 】

In multimedia conference room or home theater, in addition to the indoor acoustic environment having a certain impact on the sound field, the placement of speakers is particularly important. On the premise of a good indoor acoustic environment, the more accurate the sound image positioning and the more realistic the sound color, the more lifelike the live effect of sound image integration can be displayed. Next, we will discuss the placement methods of three front (left, middle and right) speakers, surround speakers and subwoofer speakers in turn.

1. Placement of middle channel speaker

The front center speaker is generally placed as close to the center of the image screen as possible. The middle speaker has the greatest impact on the sound quality of language. In order to ensure that the dialogue is accurately positioned in the center of the screen and the sound is clear, a separate speaker specially designed for the middle channel should be used. Most of the central channel speakers are horizontal and horizontal boxes, and the best placement position is the top of the TV (if the front projection display screen is used, it should be placed behind the screen), that is, it should be as close to the screen as possible.

2. Placement of left and right channel main speakers

The placement of these two speakers is related to the position of the middle channel speaker. In order to ensure the stability of left and right movement of sound image, they should be placed on both sides of the middle channel speaker respectively, and these three speakers should be kept at an equal distance from the position of the best listener in front of the screen. Generally speaking, the position of the center speaker should be a distance back from the left and right speakers until the two sound fields can be completely combined to create a truly unified sound image positioning. In addition, the vertical height of the left and right channel speakers should be 0.3m lower than that of the center speaker. Otherwise, the height difference of the left, middle and right speakers is too large, and the sound image in front will give people the feeling of sound image jumping when it is shifted laterally. Generally, floor speakers can meet the above requirements. If Bookshelf Speakers are used as left and right speakers, they shall be fixed on the speaker support to make its height meet the above requirements.

The distance between the left and right channel speakers from the screen is related to the size of the screen. If color TV sets with large and medium screens are used in small rooms, the left and right channel speakers can be close to both sides of the screen. If the screens are small, you can make them a little farther away from the screen to obtain a wider stereo sound field. To sum up, the sound directivity of the speakers of the left, middle and right channels is more important than diffusion, that is, the radiation angle range of the three channels should be mainly towards the best listening position. In this way, the influence of reflected sound from floor, wall and roof can be reduced, and the clarity of sound image positioning can be properly ensured.

3. Placement of surround speaker

The placement of surround speakers shall be different according to the audio-visual environment (room conditions) and the type of loop speakers. For the speakers with left and right surround channels, the sound diffusion should be more important than directionality, which is conducive to creating a strong surround atmosphere. When placing dipole speakers, we should focus on two factors: resonance and self attenuation. The best anti resonance position is 20% of the indoor space height from the ceiling (or ground). In order to make the frequency response smoother, a new device called low-frequency "trap" (absorbing low audio) can be added to eliminate the reflection that leads to sound self attenuation.

There are many layout schemes for direct radiation ring speakers. For example: fixed on the walls on both sides and make them point to the rear corner; Fixed on the rear wall so that they open outward and upward in an inverted octagon shape and face the junction of the side wall and the ceiling; Put it on the floor next to the wall on both sides, and point upward to the junction of wall and ceiling, etc. Many other schemes can also be designed according to the specific conditions of the room. The surround sound field of the home theater is mainly formed by the sound reflection and refraction of the indoor anti sound face to the surround speaker. The indoor acoustic conditions of different rooms vary greatly. As long as you test patiently and compare carefully, you will be able to find the best placement scheme.

4. Placement of subwoofer

Usually put the subwoofer near the front corner, preferably more than 1m away from the corner, so as to reduce the interference of standing wave. You can also place the subwoofer on both sides of the best listening position and keep an appropriate distance, because the human ear is not very sensitive to the direction of the subwoofer from both sides, so the subwoofer will not interfere with the original sound image positioning of the three channels in front.

The following methods can effectively help find the best placement of the subwoofer: put the subwoofer in the best listening position (temporarily remove the nearby sundries), connect its speaker cable, play a piece of music with strong bass effect repeatedly, and then listen carefully around the room. When listening, the ear should be close to the ground and roughly at the height of the subwoofer. At this time, find out the most stable, deep and clear point of the bass, which is the best placement position of the subwoofer.