【 Weak current College 】 speaker design and installation configurations---Power By 【 China power house network 】

Any high-quality audio equipment of one of the important element is the ability to output the sound balance and stability, even reaching every corner of the room.


Used to measure the sound in different environment of volume units called sound pressure, in decibels (dB). Humans can hear the minimum volume of 0 DB (1000Hz). But once there are more than 140 decibels can make people feel pain.


Just know that the specifications of the speakers, you can calculate the speakers in the room of sound pressure. Calculation formula in later chapters.


In the scope of the calculation of the speakers, first of all let us understand the speaker's features.


Speakers of the most basic difference is the radiation angle (openingangle). That is, each with a different sound beam coverage.


In General, there are suitable for use in large spaces, and suitable for wide speaker for outdoor use of narrow angle of the speaker. Narrow angle speakers can make sound set, when used outdoors can avoid sound effects too separated, or neighbors. Narrow angle loudspeaker for indoor use, it will sound in the audience area, not walls due to the rebound causing distortion.


Another item to note is that if your microphone and speakers in a room, and the coexistence of the speaker selection or improper installation location, easy to produce a whistling sound made microphone or sharp noise.


While some speakers cannot produce a wide-angle coverage, but there are ways to transfer the sound set, so that the sound transmission directional, this part will be in later chapters in detail.


Ideal PA systems should be, at any point coverage area can hear the same loudness, sound the same definition. In the design of the system is also important to note the following:






The location of the audience, at least, be included in a


The speakers sound radiation area


I. uniform distribution of speakers

Throughout the region, the speaker distribution to uniformity, to avoid making the audience feel close to the speaker volume is too large to make people feel uncomfortable. At the same time to prevent weak tempo (sound too small or completely inaudible)


Second, the appropriate sound radiation angle

When using 4KHz signal measurement, most of the radiant cone angle of the speaker angle is 90 °. Some speakers (such as a heart-shaped pointer to type) of the horizontal and vertical radiation angle is not the same. Vertical mounted speakers, its vertical radiation angle on sound field uniformity also played a key role. Design should pay attention to when the position of the guaranteed audience is included in at least one of the speakers sound radiation area.

Third, ceiling speakers interval

In the rooms needs sound field more uniform, ceiling layout of speakers, the interval and the room height, more precise, and the audience's ears height of an imaginary plane. Affected ear height that the audience is sitting (Office, Hall) still stands (corridor). Because most of the radiant point of speakers is 90 °, so the speakers about the same speakers between radiation angle in the ear of highly hypothetical plane projection diameter.


4. avoid noise pollution

In the design of outdoor system should be taken into account as far as possible the sound restrictions within designated areas, avoiding noise interference to the neighbor. Carefully plan the location of the speakers and the direction to maximize improvement such interference. Horn speaker when the 4KHz generally have very narrow radiation angle (30 °)


5. enhanced bass

If you want to enhance the bass speakers, sound columns placed in rigid wall corner, do have a prominent bass effects.


6. prevent the exchange of self-oscillation and inductive sound

To avoid the speaker and microphone between self-excited acoustic feedback, the receiver should be placed at the speaker sound radiation areas.


If the microphone cable drop location incorrectly, likely from the AC power cable from the sound of induction AC, so must the power cord from the AC 220V 50 Hz or above, or be 50cm shield. Similarly, the microphone cable and loudspeaker cables too close or have feedback, the formation of self-excited oscillation, and therefore must be separated by 50cm above.


7. connect with phase

Speakers must connect with phase-to-end, if two adjacent speakers connection phase instead, because the phase of interference in the sound pressure level lower. Speaker terminals are generally marked with the phase marker, such as "0", red dot or red cables, etc. It should be noted that the same phase of terminals connected to the same output line.


Public broadcasting system usually major broadcast background music. In offices, living rooms, changing rooms, floors, walkways etc should be equipped with 1 ~ 3 watt speakers, room 0.05 w/m ². Corridor speakers spacing by storey 2.5 times consider that there is a ceiling of Environment General Yi ceiling installation. Both ends of the floor corridors, Hall, conference rooms, restaurants, shopping malls, bars, function rooms, rooftop garden and other places where into the public broadcasting system in place, the installation of 3 ~ 12 Watt speakers or small sound columns. Storey 2.5 meters of expressing 3W speakers, spacing to storey 2 ~ 2.5 times; the story of 4 m and above, the use of 3 ~ 5W speakers, spacing to storey 2 ~ 2.75 times. Speakers should be combined with the architectural decorative ceiling spaced arrangement, and overall speaker power density should reach 0.025 ~ 0.05 w/m ².


If you have already selected the exact location of placing the speakers, the following are some practical examples.


1. speaker placementLocation must take into account the average sound to convey every corner of the room. So, do not appear in a corner of the audience room couldn't hear the sound, or forced at stand treble pressure.

General cone-shaped speakers (unlike the Horn speakers) of the best spread angle is 90 degrees, covered in the audience could hear the average sound pressure at 6 DB within the clear sound.

Because we know the speakers sound pressure, so you can evaluate:


A) maximum output sound pressure value.


B) and speaker distance for the audience receives sound pressure.


C) when the speakers sound beam overlap, the audience will hear how many additional sound pressure.


D) specific places the speaker volume, power consumption.


E) expand the machine power capacity.


2. speaker for outdoor use, often there is a sound cannot be set, or to disturb the neighbors. The use of Horn-shaped speakers you can avoid this situation. Horn-shaped speakers when output to 4000Hz broadcast an angle of 30 degrees.


Because of the Horn-shaped speakers to produce a high pressure, it can be mounted in a flagpole, light poles, and high buildings, top-down play, properly adjust the radiation direction, so you can avoid disturbances neighbouring or echo.


3. in the erection of a speaker, care must be taken to avoid creating too large. For example, if a speaker with high pressure is hung on a hard flat wall surface, you will inevitably produce echo. This situation often in large spacious room, outdoor or appear between the buildings.


Speaker placement, because of parallel walls rebound by ECHO if in room with a wall, then echo the situation will worsen. Echo in reflection to the other side of the wall, it will lead to another echo. ECHO will reverberate in space, until the sound pressure decay to hear.


You can imagine, ECHO will broadcast distortion and prevented the transmission of the music, the music has the potential to become meaningless noise.


Effective method of resolving the ECHO is the speakers are properly placed in the corner, or to place multiple smaller power of speakers in order to reduce the sound pressure to resolve.


4. echo will make the audience unable to clearly hear the speech voice parts. This situation often occurs in aircraft Hall, open warehouse, as well as the Gothic church, etc. Impact echoes often caused by up to 2 seconds continued. If the ECHO will continue 1.7 seconds or longer, you must seek expert solutions to design a better voice clarity.