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Car horn how to carry out routine maintenance and overhaul
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outdoorspeaker – China Manufacturer
Thank you for inquiry my outdoorspeaker, Tel: +86.573.8468.1673, E-mail: futuresound@mailzj.cn
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The car horn is the frequent use of the device while driving, if the speaker fails, the car will be very inconvenient. Sometimes according to the speakers, the sound is not like a mosquito called, is very hoarse, even voice. This is exactly what is causing?
Let\\ s look at the speaker is how it works. When the horn button press on the steering wheel or other location, the current from the battery through a circuit toward the horn relay, solenoid coil, solenoid coil to attract the moving contact of the relay switch is closed, current will flow to the speaker at the . The current speaker internal electromagnet, so that the diaphragm vibration and sound.
According to the author\\ s experience in many speaker failures, there is a problem often is the fault of the speaker itself. In particular, speaker installation location of some of the automotive design is flawed, and very easy to make the speakers to rain water when it rains, causing damage to the speaker. Common parts of the fault when the speaker does not ring, no more than 3:00, that is, the speaker itself, the speaker switch contacts, as well as the speaker wiring harness, when failure to refer to the following steps to check.
Sometimes does not ring horn switch, if the speaker is sometimes loud and sometimes does not ring, multi-speaker switch contacts within the contact is not good, but also some of the speaker itself.
Second, hoarseness multi-plug connection is bad, especially the steering wheel around the various contacts, due to frequent use, easy to make contact frayed.
Three and did not ring the first to check the fuse to see if the fuse, and then disconnect the speaker plug with a multimeter to measure whether there is electricity here in the horn switch. If there is no electricity, should check the speaker wiring harness and horn relay; if there is electricity, the speaker itself, then you can try to adjust the adjusting nut on the speaker, if it does not ring, you need to replace the speaker.
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Decoration home listening room the attention
Web Design And Seo For www.china-webdesign.com
woofer speaker – China Manufacturer
Thank you for inquiry my woofer speaker, Tel: +86.573.8468.1673, E-mail: futuresound@mailzj.cn
http://www.chinafuturesound.com/key-woofer-speaker-25/
1, door and window treatment
Doors and windows of the purpose of sound insulation, sound absorption and dust.
A lot of noise into the interior doors, windows. Good wooden doors, shutting to indoor noise level lower (10-20) db. If the number of door frames covered with sealing tape around the total can reduce the noise level (14-18) db.
Outdoor sound is noisy, it is recommended to install double glazed windows. The general living room windowsill width of about (12-15) cm, the sill edge to install a layer of glazing to prevent dust, noise, thermal effect. Double glazed windows can reduce outdoor noise (14-18) db; if we covered with sealing tape, can be reduced (18-20) dB. If conditions permit, the installation of aluminum windows, made the push-pull, space-saving, easy to use, easy to distort, good sealing, and its performance is superior to steel window.
If the families have to install air conditioners, air conditioning ducts into the sub-outlet, is also the noise of the entrance; If you have installed the TV room
Antenna, the antenna into the side noise entrance. Should these pipes is extremely interfaces to deal with silencer.
Curtains, curtain and tapestry of sound absorption material, exquisite luxury accessories. Velvet and velveteen curtain, curtain materials, can reduce the resonance of the acoustic wave reflection and glass windows. Velveteen curtains absorption coefficient of 0.31-0.47, in the long fiber curtains absorption coefficient of 0.15-0.27, while the double-layer velvet curtain made of sound absorption coefficient, up to 0.69-0.82.
2 on each side of the indoor handle
Respond to ground to sound insulation and acoustic treatment. The best carpeting, its sound absorption, sound insulation effect is more ideal. Typically, ordinary Chinese fiber carpet is about 0.5-0.71, real wool carpet sound absorption coefficient of about 0.68-0.82. The erection of wooden floor, but to paste the strips of wood can also be limited to conditions. Wooden floor of the absorption coefficient of about 0.03 – 0.05. Sometimes people are willing to paste Shop plastic bricks or tiles, their sound absorption and sound insulation performance is poor, plastic flooring sound absorption coefficient of 0.02 = – 0.04, terrazzo scenes sound absorption coefficient of about 0.01 – 0.03.
The ceiling is also an important way to introduce noise. Those of poor quality, the roof of the floor thin ceiling easy transmission, beautiful and sound insulation, high-impact is very small room.
Also on the four walls of the processing. The common wall is dry plaster brick wall, its absorption coefficient is very small, about 0.02 – 0.04 can be made to the four walls to the wooden walls; made of wooden dado height was (0.8 – 1) m, dado should maintain a certain distance from the wall, not less than 4cm in the formation of cavities between the Wall and to increase low-frequency sound absorption effect. The specific practices of the wooden dado can have many kinds of users can also create their own update to support if the wall changed loaded into wave-like, circular type, patch type, and so on, can be significantly improved stifled within the acoustic conditions.
Usually more than whitewashed wall or fold gray spray, spraying latex paint, color spray or other coating, similar to the absorption effect. But also the conditions in the wall concerned about upholstery, wall covering from the wall (3-5) cm is appropriate. The wall covering can enhance the sound absorption effect, but also beautify the room.
3, indoor furniture, furnishings
(A) A typical data
Many of the home listening room to listen to music, but also to receive guests, to achieve the unity of the audio-visual enjoyment and aesthetics. The common room height are relatively low, only (2.4-2.8) m, in order to take account of the listening effect, should make the width of close to 1.7:1 is better. The general area of ??the listening room is larger than 15 square meters, in order to playback stereo, two speakers spaced approximately 2-2.5 m, which will help expand the stereo image group.
(2) furnishings skills
Indoor furniture placed should seek the easy to use and the room nice. Furnishings furniture, try not to take symmetric to prevent coloration. Do not place the vibration caused by indoor items such as metal painting, thin shell, lightweight exhibit, etc., their vibration will affect the playback effect.
Room placed in the cabinet, bedroom cabinet, sofa, etc., improve the absorption effect is very obvious, particularly to improve the low-frequency effect is particularly obvious. The average room can not install the perforated plate resonator, and therefore do not facilitate the absorption of low frequency. Overcome this drawback can be placed in wardrobe.
Glass window hung a thick curtain, wall hanging tapestries, floors, carpets, bed in bedspread, can improve the acoustic conditions. The curtain of low-frequency transmission performance is better, and glass windows on the low-frequency sound absorption performance is better, they have complementary roles.
(3) reverberation time fine-tuning
Indoor reverberation time should be controlled within a certain range. Long reverberation time, voice trailing echo, through the laying of the carpet, hang decorative curtains and other measures to increase sound absorption, and even indoor decoration dolls, plush toys, flowers, pots, etc., can improve the sound absorption effect. If the indoor reverberation time is too short, sound dry, should increase the reflecting surface can be hung on the glass mirror, hung a large picture of the glass frame to improve the indoor quality.
Still a lot to improve sound quality way. Such as indoor flying a variety of chandeliers, wall paste calligraphy and painting or hanging crafts, not only beautify the environment and also to improve the reflective properties. Shelves, some enthusiasts are placed in the room on a shelf filled with different sizes of books, magazines, or CD, analog record, etc., these items on the acoustic absorption, reflection, mines scattered; on the shelf layer of anti-set size, the width of the book, can produce an irregular surface. For those difficult to deal with a large area of ??reflective wall, try placing the shelves, and can also improve the listening effect. In short, through a variety of adjustment measures, and finally let people hear the speaker issued a pleasant and harmonious sound prevail.
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Car subwoofer tuning the Heart of the three
Suppose you have a car sound system equipment, electronic crossover, or host, built on a pre-amplifier crossover function (without
these features it is difficult probably a modified subwoofer), then installed a car subwoofer system , is bound to face will have three
mixing steps: subwoofer phase, subwoofer with bass volume a sense of connection and frequency settings.
In these three steps before the start of mixing, we must first set the car in the high-pass subwoofer crossover point. Basically, the
subwoofer can extend down to lower the frequency the better player out, but because of the physical nature of restrictions to the
general car stereo bass speakers installed through insulation, damping treated front door panel, for example, the top frequency more
down to the 60-70Hz, and then will begin to go very low loose, vague, so we caught the high-pass subwoofer crossover point, from
about 65-90Hz can be set in order to be able to filter out the bass better low frequency speaker loose.
1 subwoofer phase setting: as long as the subwoofer in the operation phase will have a sound problem, and this set the subwoofer to
be adjusted based issues, if not, it may form a subwoofer sound system and the subwoofer the sound of fighting each other, that is,
the amount of sense to set subwoofer system more, but less bass sounds.
The actual adjustments, as long as you or from the electronic crossover frequency on the amplifier settings to test, as found in the
low-pass subwoofer crossover setting higher, the greater the volume is turned up, but the music sounds more bass less, that is, the
phase setting is incorrect, it is necessary to adjust or phase reverse the subwoofer line the way to correct subwoofer phase!
2 subwoofer crossover settings: in the car stereo, subwoofer low-pass crossover setting involves not only the balance of music
listening, but also involves the accuracy of sound field! You may have heard, some people say that because many car subwoofer
equipment installed in the rear luggage compartment, so the subwoofer can be hit by the car forward over my son.
But think about it, it was a concert to listen to audio speakers on the back of the head of it? This concept is definitely not the right
sound! Therefore, even if the car subwoofer in the rear luggage compartment mounted equipment, we still have a way to get the
subwoofer sounds like the passengers in front, and this was to spend one o clock acoustic theory – the higher the sound frequency,
the stronger orientation ; lower the frequency, sounds more spread, the more directional.
Therefore, in general, when we put the subwoofer low pass crossover set at between 55-75Hz, the frequency is so low is not prone
to the problem of direction, that is, to the human ear, not easy to hear bass surplus came from behind his head, and then with the
sound field in front with the car a good subwoofer frequency interface, you will hear are like the front of the subwoofer came with
the correct positioning of the sound field .
Other readers to know, even in the 55-75Hz frequency in this section to set the subwoofer s low pass crossover, musical sounds, or
have different changes, basically the lower the crossover point set, the sound field more reach, more broad, more flexible bass sounds;
higher crossover, bass impact, intensity of feeling stronger, two features can not have both, depending on who s listening preferences
audio mixer!
3 sense of ultra-low volume settings: adjust the amount of sense to set the subwoofer system is the easiest, but also the most error
-prone steps! Many people might like to re-taste, the volume of the subwoofer system to increase the bass was very large, not
knowing the state increased dramatically in the bass, the low over the audio band is probably a distortion, and how could such a nice
music? Therefore, the correct sense of ultra-low-volume adjustment, in fact, as long as the subwoofer sounds a little bit of feeling
enough, or should the main bass bass from car speakers.
car audio characteristics of the host audio signal output
In the car audio field, now the most used way is to output the analog signal output, such as built-in amplifier to directly drive a small
speaker, but also the first low-level signal output to connect to an additional power amplifier. Analog audio preamp output is used in
car audio red and white RCA connection, the connection of other audio / video products are more common, but in car stereo, the
two colors represent the analog audio signal input and output, and almost all of car audio products, and are based on the RCA
connections, including equalizer, power amplifier.
The output analog audio signals, there are four types: single-point grounding type, balanced, floating and differential. This is the
original car audio systems and after-market car audio compatibility is a very important key. Usually a type of audio output can not be
compatible with another, even though they may choose the same RCA connectors. Many after-market car audio and video host of
audio signal output is very simple, it is a single-point grounding type. High output of the host that drive speaker directly, its output is
the use of floating. But the original car the host are generally in a balanced output or differential output, which is after-market audio
products have a greater difference.
Some High-end level of the host or CD disc CD box with digital audio signal output, the DVD host, digital audio output but also a
standard. The digital audio output must be D / A digital-analog conversion, the digital signal into an analog signal, then output to the
amplifier. Now, there are several little-analog converter to power amplifier to receive digital signals. Hosts the DVD, the digital audio
signal output decoder will also require the use of multi-channel signals into separate channels.
The output of digital audio signal output method is commonly used fiber optic signal output, it uses POF (plastic optical fiber cable),
and analog signal output by the use of copper signal lines are completely different. Optical digital audio signal is converted to a signal
light pulse signal, it is not all finished inside the electromagnetic interference. Fiber connections of copper wire and other differences in
the way, to ensure signal purity, optical fiber signal can not bend over so as not to have an impact, especially in fiber length and fiber
optic cable production methods, are required to take into account optical signal transmission. Of course, the use of fiber optic audio
signal processor also requires it, and then the optical signal into an analog signal. This input is very common in the civilian market, but
relatively rare in car audio. Fiber-optic signal connector commonly used to connect both ends of the head with a standard TosLink fiber
cable POF, this connector is designed by Toshiba Toshiba and named.
Digital audio signal output connection is also used in coaxial signal output, similar to its Connector RCA connector, the difference is
between them is the use of one-way coaxial system, the digital audio signal transmission to the D / A converter, in order to match
between the equipment, the use of RCA coaxial connectors, the standard should be 75 ohm coaxial cable shield, and only one wire,
braided shielded cable is out.
Technical points of the host audio output
Audio audio output to the host they connect with the equipment to match its technical points are worth our attention, they are
related to the performance of the entire sound system. Main points are:
1, the signal to noise ratio S / N Ratio
This parameter is the source of the sound system for the entire system to produce heavy burst of new noise ratio, and its noise are
thermal noise, communication noise, mechanical noise, and so on. The indicators for the general detection of rated output power of
the playback signal with no signal input system noise output power ratio of the number of decibels (dB) to represent. The higher the
better the audio signal to noise ratio, the higher signal to noise ratio of equipment that it produces less noise. Such as CD players up
to 90dB signal to noise ratio above, high-end even reach l10dB more.
2, pre-output level
Pre-output level is a very important parameter, because it will affect the audio chain, the lower product-related parameters. It is given
in volts. Output from the host level or at least the processor in the power amplifier input sensitivity adjusted to the lowest, nor will
they produce overload distortion, sound system will not produce the slightest sound. When the sound system is used to hear voices
or music, the host of the amplifier output level and input level of the best ratio is 2:1, that is, if your host s maximum output is 4V,
then you The maximum power amplifier input level best to 2V. In any case adjustment, the best match is the power amplifier without
distortion, maximum power output. Despite the higher output level of the host, it seems that the more power amplifier can drive, but
in reality, we must consider the level products matching the input sensitivity. For example, the amplifier s maximum input level is 2V,
then the output level is not appropriate host 8V.
3, the output impedance
This parameter is considered connected to the host with the lower equipment matching issues. Output impedance is the ohm units.
The actual output impedance varies with frequency, so the nominal output impedance is actually based on a specific frequency
measurement results. In general, the pre-output impedance ranges: 50 Euro to 1000 Euro. Generally considered to have low output
impedance of the host is excellent, but in fact, this also represents a large current output. The advantage of high current or power
amplifier connects multiple processors. When connecting a single power amplifier, then the size of the output impedance is essentially
no difference, but when connecting multiple amplifiers, and a Y-shaped sub-line, then a low impedance high current output level
before the host is the best choice . In practice, make a sound pressure in the car, preferably in such a low impedance of the host.
Stones from other hills may serve to polish jade passenger vehicle networking systems of reference
Mainstream domestic passenger car business networking technology spread, intelligent operating system released in stages, for
networking in China s car industry go? Europe and developed countries, technology has matured, stone hills, or jade?
Europe and other countries, car networking technology overview:
U.S. and European car companies earlier application vehicle networking technology management team, such as Man, Volvo, Scania,
Mercedes and other companies, while passenger transport companies in Europe and America also actively use the relevant technology.
In addition to Europe, Japan and Taiwan in the vehicle management system development is also done a lot of attempts to obtain
good results.
Scania Fleet Management System Description:
Sweden s Scania s fleet management system introduced by GSM / GPRS, driver information and vehicle to achieve the wireless
transmission of data, can provide road passenger transport management, driver management, vehicle management. Management of
road transport include easy to understand and record the fuel consumption display, the vehicle condition display, to help drivers and
transport companies to quickly understand the content needs to be improved. This feature can monitor vehicle location, maintain the
fleet location and status tracking. Upon receipt of a new task, the system can view the status of the vehicle can be used, as well as
the progress of the task being performed, you can drive to maximize the efficient use of personnel and vehicles will help master the
exception occurred. When the v
subwoofer car audio installation purposes
There are car people for car audio sound quality very seriously, especially in the music s overall performance higher, after installing the
sound does not always feel nice little something, this is the lack of subwoofer. The purpose of installing the subwoofer:
Many people install subwoofer is blind, that felt great sound is good, and some people think that installing the subwoofer in order to
listen to “disco, rock and roll” and set up, do not listen to other music subwoofer, which are is wrong. So why is it to install
subwoofer? What is the purpose?
1, motor cars and friction in the tire and road noise, engine noise, wind and vehicle conditions often make the internal structure of
bass has been weakened, especially in fast speed, due to the impact of noise, heard very little bass. Install the appropriate high-
performance subwoofer to enhance the bass region, can be an ideal solution to this problem.
2, the general focus only on the host and install the audio treble, bass up to, for example: 6 × 9 inches, although the speaker of the
indicators give a wide frequency response indicator, but when the decay reaches the subwoofer area badly, so the performance of
this band is not prominent. Only dedicated subwoofer to compensate for this band, the bass extension, in order to make a complete
music player. Thereby maintaining the natural tonal balance, it sounds rich depth, breadth, fullness, and clear and pure.
new line of car audio cables if you want to burn
Often with pot enthusiasts on the topic to the new line, the answer is yes, in practice, the new line is to burn like a new car to run a
major general, in a moving car can be gradually adapted by a variety of working conditions, of course, The running-in process is
gradual, car people know, the life of the car run-in period of great influence, future cars and good run-in period is also open to a great
outdoor garden speaker
relationship. Although the car is not like a car stereo wire the same mechanical structure, but the truth was burning and vehicle line
running exactly the same. The reason why car audio wire and other wire of different, largely related to its internal structure, core
materials, processing technology, the arrangement of the crystal as well as signal flow are very demanding. Individuals that, in normal
horn speaker
use, for a variety of high and low frequency and amplitude of different sizes, a broadband spectrum of music signal, gradually the
crystal structure of the molecular wire slowly straighten out the form neatly arranged, the largest extent by the resistance slow the
music signal to reduce signal loss, so that the signal transmission as the perfect circuit to the next level, this process is like running in
power speaker
front of that car must be slowly, gradually, the effect will be better , all the haste of the crash probably not a good way. Moreover,
the long line through the burning process, seriously appreciate the wire quality, flavor changes, which in itself is a great fun ah!
So how to burn it?
Different wire because the different materials, the need to “burn” the length of time is different. General “pot” 5-6 hours began to
have significant changes, and some wire in order to get better sound, to “burn” 400-600 hours. If the car audio equipment, set aside
a long time without use, the next use also requires a period of “pot” line. As to how “pot”, the general power to take a large pot or a
long time on the audio equipment, such as playing back large frequency width of music, or if there is Beethoven s piano music
collection is very good …… and so on.
good car audio is out of tune
audio-subwoofer-31/”>
Whether it is domestic or imported, and every car is equipped with a car stereo. Although many owners of their car audio sound
quality do not care, but there are still a lot like listening to music on the carriageway of friends tried to modified car stereo, they want
their car to hear the perfect blend of sound effects.
In other countries, are converted by the audio car audio experience, know how to play with a professional sound company to be
modified them according to their expertise, to provide for the different needs of brand owners and sound technology. But domestic
car audio conversion, most are located in the automotive supplies and decorative automotive beauty shops, and as they are lack of
operating experience and sound knowledge of audio unskilled laborer, only use equipment and prices for brand owners of publicity,
the sound is not already familiar with the owners of mistakenly believe that this is the entire contents of car audio conversion. Modified
after the discovery of many owners, their car audio conversion effect, and the effect of their very different previously thought, and
some even less original sound. These so-called modified the original, in fact, put the removed equipment and skilled operation.
Modified car stereo key is whether we can effectively debug. As the car space narrow, slightly wrong, it sounds very uncomfortable.
This is not the same sound at home. So even the famous sound, if debugging is not in place, the same will not have a good voice.
Therefore, in the domestic car audio market is not mature, owners should think twice. Conversion process also includes equipment
with a selection of genuine brand recognition, performance of the play equipment, applications, design changes in a fixed position,
mold making, and so reasonable. Car audio as a commodity, in fact, only a semi-finished products. But the real complete conversion,
you must rely on debugging. Therefore we can say, debugging is successful, it can really reflect your car s audio conversion was
successful.
Do not ignore the door of the converted audio processing
In the conversion process, the focus in the following three aspects of the door handle in order to achieve the purpose of high-fidelity
sound.
1, damping
Installed primarily to minimize the vibration speaker vibration around the site, because of the speakers at work, cone generated by the
vibration of the plate will lead to the surrounding parts of vibration, so that cone vibration of nonlinear distortion, affect the overall
sound quality.
Vibration method is generally fixed damping method, that is, the inside door, pasting large vibration plate such as hardness, plastic
sheet and so on. The installation position of the speaker, simply use the surface to increase the rigidity is not enough, the best is
good to install rigid washer. In the higher conversion in the door to re-mold, to increase its rigidity.
2, noise
As the special nature of the car, the car door handle vibration, but also to do the appropriate processing of noise, noise is isolated
from external noise and the car s engine sound in a moving way, road noise and wind noise.
Approach is to reduce the noise of the incoming solid noise, damping materials in general, will also be done using double-acoustic
insulation materials handling, while the engine hatch, firewalls, etc. can be affixed to cover vibration materials. In order to filter out the
noise coming from the air, in the automotive environment, the more difficult to handle. Generally only done on the car s sealing
process, that is, the rubber side of the car to do a good deal, especially in the conversion process repeatedly removed, will make it a
bad seal. Year high in the car, the best heavy equipment side of the new rubber.
3, sealing
As the front door just as the sound field speaker cabinet, so the requirements of the door seal is very good. There are numerous car
door repair holes, if not addressed, will make the speaker on the back of the sound emitted in opposite phase relative to interference
with the front of the sound, especially the longer-wavelength low-frequency attenuation serious.
In Hi-Fi car audio component speaker, if the door handled properly, will make a good low-frequency response of the top set of sound
greatly reduced. Sound field before conversion, the sealing approach is the use of stereotype or aluminum, etc. will repair the hole
closed, and all parts of all sealed with plastic good. This will enable the low-frequency extension dive lower, resulting in good control,
enhanced voice clarity.
car audio conversion tips
In the audio conversion, the amplifier, speakers, like the conversion is very important, and audio equipment is installed, the layout of
the sound will have a significant impact.
Door noise: cars in the fast-moving, while high-speed driving, wind noise, tire noise and mechanical noise will interfere with sound
system. Hence the need to retrofit vehicles. Generally choose to do shock and noise of the door. Generally use a soft sponge foam to
seal the door cavity, the best is to use a professional shock plate. speaker position with stress: car audio conversion, the high, middle,
bass speakers have separate, if installed together will interfere with each other. As one owner modified his Audi A6 in sound when
loudspeakers installed in the A-pillar on both sides, tenor horn installed in the front door in the middle front position, while the bass
speakers installed in the front door at the bottom. According to the modified technicians introduced, it is a good alt link between the
formation of an accurate sound field positioning. Moreover, it can be modified at any time split down.
Speaker clever layout: Many owners choose to speakers when converted into hiding, using built-in, it saves space, is a very practical
choice. You can also choose the irregular shape of the speaker, so you can maximize use of space, and the irregular shape will help to
eliminate the interference between sound waves.
Why would the noise sound system?
1, the electromagnetic radiation interference noise: stray electromagnetic radiation interference environment, such as mobile phones,
walkie-talkies and other communications equipment, high-frequency electromagnetic radiation interference, the surrounding
environment, elevators, air conditioning, automotive ignition, welding and other electrical pulse radiation, the use of studio lighting
control thyristor control of the radiation generated by the equipment, will be mixed by the audio signal transmission cable directly to
the formation of noise, or poor equipment through the shielding shell of jammer interference noise within the circuit. Practice shows
that in some special occasions, such as extensive use of SCR dimming equipment, studio, etc. If you do not take reliable shielding and
grounding, noise will be very serious. Or audio equipment is not working.
2, power interference noise: sound equipment external interference, in addition to electromagnetic radiation vehicle mode, the power
part of the introduction of unwanted noise will be another main reason for noise. City power grid for a variety of lighting equipment,
power equipment, access control devices together to form a very serious source of interference. If connected to the grid in the same
light control equipment, air conditioning, motors and other equipment will be generated on the power line spikes, surge current, the
ripple voltage at different frequencies, through the power lines fleeing into audio equipment, power supply, the total interference
noise can not be part of the sound equipment effectively filter the power supply circuit, will necessarily result in the formation of noise
within the device. In particular, the same power grid is not up to the electromagnetic compatibility requirements of high-power
devices, is the main reason for interference with audio equipment.
3, the ground loop noise: the sound system, the system must require a good grounding, grounding resistance should be less than 4
ohms. Otherwise, the sound system equipment for a variety of radiation and electromagnetic induction the induced charge will not be
able to flow into the earth to form the noise voltage superimposed on the audio signal. If the ground between the different devices
of different grounding resistance due to potential differences exist, or exist in the system of internal ground loop, it will lead to ground
noise. Interconnect two different sound system, they may produce noise, noise from the two systems directly connected to ground
caused.
4, the device s internal circuit noise: sound device has an indicator — signal to noise ratio. Due to internal electrical noise generated by
electronic components in a single device can work to achieve the required targets, but when multiple devices cascaded, the noise will
accumulate to increase. Practical application, some low-level civil audio equipment, internal power supply filtering is not good, making a
great noise communication device itself, sometimes in the sound system in the formation of very serious noise.