The sound system pays attention to a match, and it is more difficult to match the sound system with the room. No matter how high your audio system is, as long as it does not match the listening environment, it will be a waste of money. One sentence is the problem of spatial distortion.
Generally speaking, the load of the sound source is the power amplifier, the load of the power amplifier is the speaker, and the load of the speaker is the room where the sound is listened to.
Spatial distortion refers to the difference between the sound output of the playback system and the sound input into the human ear. This distortion is mainly caused by the resonance standing wave of the room, due to the walls, floors, ceilings and various objects in the room, or the absorption or reflection of certain frequencies. The initial delayed sound and the later delayed sound caused by the reflection of direct sound are intertwined with each other to cause distortion, or the directionality is narrowed due to the poor placement of the speaker, and the original sound field cannot be reproduced. For the above problems, due to the different rooms and the different performance characteristics of various devices, even an authoritative expert can hardly have a unified standard, and can only debug and match according to their actual conditions.
1. Matching between room size and machine power The power output of the power amplifier must be selected according to the size, height, volume and other conditions of the room. It mainly guarantees a certain sound pressure during playback, and basically matches the power of the speaker. If the power is too low, the volume is not enough, and if it is too large, it will cause waste. According to the experience of general households, the rated output power of the amplifier is 20W ~ 50W, and the rated output power of the stone machine is 50W ~ 100W.
Second, the spatial size of the listening room In order to avoid standing waves, the ratio of the spatial size of the room should be appropriate. Eliminating or at least avoiding sound waves resonating at a certain frequency due to surrounding walls can greatly improve the sound clarity during system playback. Once resonance occurs, it will be difficult to eliminate. A room with fixed size and decoration, not all high-end equipment and sound sources can be perfectly reproduced. The frequency of standing waves in the living room of general households is relatively easy to be in the range of 80 Hz to 300 Hz. According to the introduction of many materials, the ratio of the length, width and height of the listening room should be 1.618: 1: 0.6. If the room size is too different, you can During the decoration, the height of the ceiling is adjusted to make up, and the width can be adjusted to adjust the thickness of the wall decorations (such as TV walls, wine cabinet walls, antique shelves, etc.).
Third, the reverberation time of the listening room For different sizes and structures, especially rooms with different materials on the six sides of the room, there are different reverberation times. The length of the reverberation time is mainly in contradiction with the clarity of the sound. The reverberation time is too short, the sound is dry and dry, the reverberation time is too long, the sound is confusing, and a lot of details will not be reproduced in the sound field, greatly affecting the appreciation The effect of music.
The reverberation time refers to the time required for the reverberation energy to decay by 60dB after the sound source stops producing sound. Its calculation formula is introduced by many newspapers and periodicals:
T60 = 0.163V / Sa (where: T60 is the sign of the time required for the reverberation energy to decay by 60dB, V is the volume of the room, S is the sum of the six areas of the room, and a is the average sound absorption coefficient of the materials on each side.)
We know that when most rooms are renovated, it is impossible to design only for the acoustic requirements of the sound. And V and S are unlikely to change much (the price is too expensive), so it can only be solved according to the actual situation.
First, the speakers should be placed on the left and right sides of the room wall (wide). The center-to-center of the speaker is about 0.7 times the size of the short side of the wall. The back of the speaker is about 0.5 to 1.2m away from the wall. If the speaker has a rear inverted hole, it needs to be adjusted a few more times. The front of the speaker speaker should be as long as possible. If it can pass through the dining room or kitchen and communicate with the outside through the door and window holes, it is better to open or close the area of ​​the door and window holes to adjust the absorption and reflection of sound waves.
Secondly, high-strength gypsum fiberboard is used for the ceiling, which is set around the room, with a width of about 0.7 meters and a height of 0.3 meters into an inner hollow type, which can completely absorb sound. It is recommended not to hoist the entire room. The embossed bricks made of gypsum are used to set up TV walls, wine cabinet walls made of wood boards, antique shelves, etc. The walls are almost occupied, and the remaining parts are painted with latex paint.
The rest is indoor furniture and ornaments. The position of general furniture is not easy to change, mainly the position of curtains and wall ornaments and carpets. If the walls of the room are flat and hard, and there are smooth floor tiles and granite floors, there is a strong reflection. This will increase the area of ​​the curtains, add hanging ornaments on the walls, and add rugs on the ground for centering. , Treble for some hedging and improvement.
After the above work is done, let's listen to the room's listening effects:
1. If the sound of the bass drum, plucked string or euphonium sounds exactly the same, it can only mean that there may be a large bass resonance effect in the speaker or speaker, which is not related to the room, and focus on the transformation of the speaker system. This first Figure it out.
2. Compare the performance of voice and music playback. Specifically, when playing music is normal, keep the state of the machine unchanged and only change the sound source to play the voice (such as poetry recitation). The voice should be lively, clear and natural. The pronunciation is easy to understand, which is the most relevant to the room.
3. Listen to a percussion instrument, a series of strong sounds, and then listen to a plucked music to check if there is any transient distortion such as dragging.
4. Send the "Hugo Gold Disc" series to the sound source machine, play a 10000Hz continuous signal, walk around in front of the speaker, and check the relative directivity of the output sound. The wider the output distribution at high frequencies, this system and The more the listening room matches.
5. In addition to checking the resonance of the speaker box, it is more important to adjust the balance of the left and right sound fields. On the emperor's position, you can feel the sound field positioning in front of you. Especially in instrumental ensemble, the position of various musical instruments in the sound field should be obvious, and there should not be a shifting feeling with the volume change. The singing actor is in the middle of the sound field to the left, and there can be no displacement after opening.
6. The last and most important point is that the background noise in the listening room must be small, otherwise all work will be in vain.
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