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Home / News > Talking about the Matching Problem of Power Amplifier and Speaker


Talking about the Matching Problem of Power Amplifier and Speaker

In the field beats headphones of professional sound, amplifier and speaker configuration involves many aspects, such as power matching, power reserve matching, impedance matching, damping coefficient matching. In the mating to recognize the above points, the performance of the equipment used to be fully play, to achieve beats by dre wireless the desired results.

?1, power matching

In order to meet the requirements of high-fidelity listening, the rated power should be based on the best listening sound pressure to determine. Everyone has such a feeling: the volume of hours sound weak, thin, dynamic small, dull, low frequency significantly lack, fullness difference; sound appropriate natural sound, clear, round, soft and plump, powerful, dynamic larger; Big, the sound stiff is not soft, rough, there are harsh feeling. So the sound pressure level and the sound quality has a greater relationship between the sound area of ??the sound zone is best for the 80-85dB (A weight), you can listen to the speaker from the distance and speaker characteristics of the sensitivity to calculate the speaker The rated power and the rated power of the amplifier.

We all know that in the hall design, you need to determine the speaker power according to a series of calculations, and then determine the power amplifier power amplifier. First of all, usually in the human ear to listen to the domain of 20Hz-20kHz, the concentration of a large amount of energy in the music signal is generally in the low frequency band, high frequency energy is only equivalent to medium and low frequency energy 1/10, the general speaker treble loss of power ratio The bass is much lower. And the amplifier is like a current modulator, which in the input audio signal control, the output of different sizes of current to the speaker, so that the occurrence of different sizes of sound, in a certain impedance, you can achieve the nominal power 200W amplifier to 400W or (THD) will be greatly increased, this distortion is mainly produced in the low-frequency signal in the high-frequency harmonics, the greater the distortion, high-frequency harmonic energy is greater, these high-frequency Distortion signal will be with the high-frequency music signal into the treble head together, which is why low-power amplifier push the loudspeaker will burn the sound of the reasons. Second, the power amplifier and speaker power configuration and target loudness and the use of the occasion also have a certain relationship. In a certain target loudness, the music signal should be dynamic in each piece of equipment can be fully guaranteed, if the power amplifier is too large, the gain set is very small, loudness has reached the requirements, but then the amplifier gain is limited The dynamic range of the signal. Therefore, the power amplifier power can not be too large, otherwise, both a waste of expenses, will bring loudness and music can not take into account the dynamic and heavy load of the trouble.

In short, the amplifier must be selected by the speaker, in a certain target loudness, the speaker can be larger than the design value, for different purposes, and the power amplifier should be strictly determined by the speaker, not much flexibility. Power amplifier and speaker power configuration of the specific criteria should be: in a certain impedance conditions, the amplifier power should be greater than the speaker power, but not too much. In the general application of the amplifier without distortion power should be the speaker rated power of 1.2-1.5 times; and in large dynamic occasions should be 1.5-2 times. With reference to this standard configuration, both to ensure that the amplifier in the best condition to work, but also to ensure the safety of the speaker, even if the lack of experience of the operator, as long as the operation is not a serious mistake or improper adjustment of the surrounding equipment, And the amplifier work in a steady state.

2, power reserve matching

The so-called "power reserve" is for the speaker, in accordance with the AES standard, the Beats By Dre Sale" href="/">Beats By Dre Sale general speaker can be in a short time to withstand higher than its rated input power 4 times (6dB) instantaneous peak input power, that is a nominal 300W speakers, Time can withstand 1200W of input power. In accordance with the standards of the US FTC laboratory, the power supply capacity is large enough, the power amplifier can instantly output higher than its rated output power 3dB peak output power, that is a rated output power of 300W amplifier can be a short time Provides 2 times the rated output power of the peak output power (600W). If you need a power supply that can provide 1200W peak output power, this amplifier's rated output power will need to reach 600W, let the amplifier and speakers are able to completely show the various music peak signal, the amplifier's rated output power is equal to Speaker input power of 2 times.

However, this configuration, you can not put the power amplifier rated power completely added to the speaker, if completely added, the speaker is actually in beats by dr dre the bear more than its rated input power of 1 times the input power, that is, the speaker is always overload Working state, which is very dangerous for the speaker, so in accordance with the amplifier output power and speaker input power ratio of 2: 1, the only purpose is to let the speaker can express its peak output capability, but the amplifier input level control More stringent. Under normal circumstances, the amplifier rated input level is 0dB, then the power amplifier input level setting than the rated power input level 3dB lower, that is to let the 600W amplifier only work in the 300W state, when a 4 times (6dB) peak characteristics of the signal into the amplifier when the actual input level of the amplifier to reach 6 + (3): +3 dB, while the power amplifier output power at this time will reach the rated output power of l times, and The peak input power of the speaker matches. If you do not control the level, such as the same rated 600W amplifier 300W speaker, the amplifier is still in accordance with its rated input level, then the amplifier on the normal input 600W power, speakers are equal to 1 times the input power, when a +6 dB ( 4 times) the peak signal into the time, the amplifier peak output power to reach 2400W, but the amplifier's peak output capability is only 2 times, it can not send 4 times without distortion power, this time on the audio signal clipping, the sine Wave audio signal into a square wave signal, the speaker is very vulnerable to damage.

There are two ways to set the control level: the first to set the normal working level of the system are all OdB, when the power amplifier before the level of the device output level is OdB, the power amplifier to reduce the volume of 3dB; The second is to set the normal working level of the system to all OdB. And then the mixer's output level under normal circumstances to reduce 3dB.

3, impedance matching

Impedance matching is the rated output impedance of the amplifier, should be consistent with the rated impedance of the speaker. At this point, the power is in the best design load state, you can output the maximum distortion power. If the nominal impedance of the loudspeaker is greater than the rated output impedance of the amplifier, the actual output power of the amplifier will be less than the rated output power. If the nominal impedance of the loudspeaker is less than the rated output impedance of the amplifier, the amplifier has the risk of overload, Measures to solve. In terms of tube power amplifier, impedance matching requirements are more stringent.

4, the matching of the damping coefficient

Damping coefficient KD is defined as: KD = amplifier rated output impedance (equal to the speaker rated impedance) / amplifier output resistance + line resistance. As the power amplifier output resistance has actually become the speaker of the damping device, KD value will determine the speaker by the amount of damping. KD value is greater, the greater the amount of electric damping, of course, the power amplifier KD value is not the bigger the better, KD value of the General Assembly will make the speaker damping too heavy, so that the pulse frontier establishment time, reduce the transient response. To ensure the stability of the steady state characteristics and transient characteristics of the basic conditions, should pay attention to the equivalent mechanical quality factor (Qm) and the amplifier damping coefficient (KD) with. This combination must be the speaker of the audio system as a whole part of the sound system to consider. Should make the speaker feeder equivalent resistance is small enough to be small compared with the rated impedance of the speaker can be ignored. In fact, the speaker feeder power loss should be less than 0.5dB (about 12%) to achieve this fit.

5, summary

To sum up, only fully take into account the impact of amplifier and speaker matching several important factors, power matching, power reserve matching, impedance matching, damping coefficient matching, in order to make the performance of the equipment used to fully play, to achieve the ideal Sound reinforcement at the same time, to protect the safety of equipment.