How much power should the speaker amplifier choose?
1. How much power amplifier should you choose?
Before choosing a power amplifier, the first problem encountered is how much output power amplifier to choose, which is not only related to the effect and stability of a portable party speaker system, but also related to the cost of the system. We all know that there are many ways to express the output power of a power amplifier, such as rated output power, music power, and peak power. The difference between them can be several times, and some are ten times different, and the value of these output power is inversely proportional to the load impedance. That is, the smaller the load impedance, the greater the output power of the same-power amplifier. In theory, the impedance is reduced by half and the output power is doubled. Now let's define the rated output power of the amplifier. The so-called rated output power means that under a certain load impedance (usually 82) and a certain harmonic distortion (0.1% or 0.3%, etc. given by the manufacturer), a sine wave signal is fed into the input end, and a sine wave signal is fed at the output end. On the terminal load, the maximum power obtained is obtained by using the formula P=U2/R. What I want to remind everyone here is that although it is a very strict matter to define the rated output power of a power amplifier, some manufacturers are not so strict when it comes to publicity. Some use the rated power at a small load as the nominal value, and some even use the music power or peak power as the nominal value. It is suspected of misleading the public. This depends on our knowledge and experience.
Secondly, how to choose a power amplifier in a hall? In practical applications, we generally do not directly choose a power amplifier with 400W output or 800W output. Because of the size of the power amplifier output, whether the sound we care about in the hall is loud enough is not the same thing. The power output of the power amplifier of the system, in terms of type, some push full-range main channel portable party speakers, some push and pull audio-visual portable party speakers, some push stage return portable party speakers, and some push subwoofer portable party speakers, the number of effects is different. It is very large, and at the same time is related to the sensitivity of the portable party speaker being pushed. In addition, it is also closely related to the acoustic environment of the hall. The influence of so many factors on the sound pressure level (usually the portable party speaker does not sound), we can use a formula to quantify the characterization: W=10 (LP-LS+20Igr) /10LP: Test point (portable party speaker radiation distance) requirements sound pressure level in dB;
LS: portable party speaker sensitivity dB, given by portable party speaker parameters;
r: The distance m from the portable party speaker to the test point, also known as the portable party speaker radiation distance W: The driving power required by a single portable party speaker can be used as a basis to reasonably determine the electrical power output by the power amplifier. It should be noted here that the formula - generally determines the output power of the channel power amplifier. The stage return portable party speakers can be determined by 30%-50% of the main channel power, the output power of the subwoofer can be determined by 100%-150% of the main channel power, and the power amplifier power of the auxiliary portable party speakers can be determined by 50% of the main channel power. %-100% sure. Never use gross estimates, but rely on imagination to determine. If it is determined in this way, the consequences will either be wasted (the power is selected too large), or the effect will not be achieved, and it is very easy to cause damage to the amplifier (the power is selected too small), unless you are very experienced.
How to make good use of the power amplifier in the portable party speaker system
How to judge the quality of a power amplifier For a power amplifier, many people often cannot judge its quality. Just relying on the indicators provided by the manufacturer is often confusing, and depending on the price, in some cases, it is not necessarily a good product if the price is high. Today, the author will talk about how to judge the quality of the power amplifier from the actual situation of use. Of course, it is another matter to use the instrument to test the indicators.
To get a power amplifier, we can simply judge from the following aspects:
1. Appearance and packaging - The outer packaging of the power amplifier should firstly check whether the packaging box is upright, whether the printing is exquisite, and whether the information is complete (specification, origin, certification, etc.), and then whether the shock-proof filling material of the packaging is environmentally friendly. Those that are well packaged, reasonable and environmentally friendly can be considered as good amplifiers.
2. Check the appearance of the power amplifier to see whether the surface treatment of the panel is fine, whether the shell plate is thick, whether the screws and screw holes are accurate, whether the knobs, connectors, and word printing are accurate and clear. If all are relatively good, it can be considered that the quality of the power amplifier is good.
3. Turn on the power amplifier to see whether the volume and weight of the toroidal transformer match the marked output power, whether the appearance is rough, and then see whether the filter capacitor is a genuine factory product, and whether the capacity and withstand voltage are sufficient (generally, the capacity is 10000uf and the withstand voltage is 100- -200v) Whether the wiring is clear and reasonable, especially the high-power tubes: - Depending on the number, as the output power increases, the number of high-power tubes can be configured from 8 to 24 or even more.
4. Judging the protection circuit to see whether the protection circuit module is relatively simple, the regular protection circuit has functions such as overcurrent, overvoltage, overtemperature, and time delay. A poor power amplifier only has a power-on delay, no other protection measures, and the circuit is very simple.
5. The fan has low noise, no transformer vibration, and no other abnormal sounds. Otherwise, the power amplifier is a bad product.
