Audio sound size and sound quality is mainly determined by which parameters?

A, power

Power of this parameter, in fact, is a measure of the performance of a multimedia speaker of the basic parameters, only because of the manufacturer's intention to avoid, so in many product descriptions, the power becomes a parameter of no significance.

Multimedia speakers labeled power are the following:

1, rated output power (RMS): RMS power can be said to be all the power labeling method in the only truly meaningful, it refers to the amplifier circuit in the rated distortion range, can continue to output the maximum power. Also known as "effective power". The power we referred to in the previous discussion of amplifier circuits generally refers to the rated output power.

2, music output power (MPO): refers to the distortion does not exceed the specified range of cases, the instantaneous maximum output power of the amplifier circuit.

3, peak music output power (PMPO): refers to the complete disregard for distortion, the amplifier's instantaneous maximum output power.

The latter two power is in fact meaningless, because their so-called "instantaneous" is often not heard a few milliseconds. However, many manufacturers in the hope that their products power labeling psychology, often happy to use these two kinds of labeling, especially the PMPO power. Most of the speakers on the market, such as hundreds of watts of speakers are so, and even some speakers to their own power labeled as 2000 watts!

This is a joke! The real 2000 watts of amplifiers and speakers enough to make you live in the neighborhood everyone heard the sound of music in your home, that is, the real 300 watts of speakers are enough to noisy building is not quiet, is a small desktop speakers can do? No wonder the PMPO power is audiophile jokingly called "JS power".

According to general practice, the ratio between PMPO power and RMS power is generally 5-8:1, that is to say, claiming that their 300W speakers, in fact, but an output power of 30W or so of ordinary speakers!

The real brand-name manufacturers will not use the PMPO power, if the product is really excellent, why use this method to cover people's ears? So, to see the PMPO logo, at least it shows that the manufacturers have little confidence in their products.

In addition to the amplifier part, multimedia speakers in the power parameters also include the speaker maximum power and power supply maximum output power. The smallest of these three parameters is the maximum output power of the speaker. And there is a certain relationship between the three parameters, such as RMS power must be less than the maximum power of the speaker, otherwise it will burn the speaker. The power supply maximum output power must be at least 150% of the RMS power, more than 50% is the so-called "power reserve", otherwise, in the large volume or large dynamic time, the sound will be distorted (a large number of speakers on the market have this problem).

Two, frequency range and frequency response

This is the identification of the speaker sound reproduction ability of the two basic parameters, the former refers to the speaker's lowest effective playback frequency and the highest effective playback frequency of the range between the unit Hertz (Hz); the latter refers to the output of a constant voltage of the audio signal and the speaker system is connected to the speaker produces a sound pressure with the frequency of the change in the frequency and the occurrence of increase or decay, the phase with the frequency and the frequency of the change in the sound pressure. attenuation, phase with frequency and the phenomenon of change, this sound pressure and phase with the frequency of the associated changes in the relationship known as frequency response, unit decibel (dB).

Generally speaking, multimedia speakers on the frequency range of the identification of more, the greater the range, of course, the better the effect. However, the problem is that many products are not labeled as "frequency range of the speaker", but "frequency range of the amplifier circuit". This results in values such as 20Hz-20KHz that cover the range of human hearing.

Ordinary (horn) sound principle

Medium **** vibration hybrid audio, sound principle, the use of vibrators vibration sound + paper drum horn sound, we often use audio people know that ordinary audio in addition to professional audio, general bass is not enough for ordinary audio, bass is good point of the general volume is not small, this is mainly due to the use of horn sound Audio by the size of the sound unit is a great influence, so many multimedia audio directly using subwoofer, external speakers, fully expand the volume range of its sound unit, but this is a great limitation on the shape of the audio audio, which is why we see on the market are generally four square four angular reasons, and the bass effect is not very good.

Acoustic Explanation

Acoustic Psychology

When a tree collapses in the forest, it makes a loud noise, but no one is in the forest, so you can't hear it. Does this count as a sound being made? The sound is definitely emitted, because when tree trunks and branches touch the ground, they produce some sound, but no one hears it, but the sound is different for humans or other animals, so this is what is known as acoustic psychology (Psychoacoustics).

Principles and history of acoustics

The principles of acoustics that I've described here are primarily intended to be used by a sound mixer to understand the various aspects of acoustics, not to conduct an acoustic research study or a master's or doctoral dissertation on acoustics, so the acoustic theories that I've described in this book are practical and can be utilized by people who are in the field of acoustic operation.

Electroacoustics was born in 1915 when an American named E. S. Pridham attached a then-existing telephone receiver to a horn that played a record player, and the sound could be heard by a crowd celebrating Christmas in the city of San Francisco. When the end of World War I, in the United States, President Harding (Harding) inauguration, the United States of America, the Bell Company to the telephone's moving coil listener connected to a record player at the time of the horn, the sound can be transmitted to a large crowd of people to watch the presidential inauguration, and therefore produced a lot of professional audio research and development of sound reinforcement engineering this discipline. Sound researchers are not simply trying to improve the sound equipment, but also do a variety of different audio experiments to understand the human response to hearing. But the highest level of audio researchers with the same understanding of acoustics is to be a holistic approach to research, to understand every aspect of the audio equipment, and human physiological response to hearing, they have made a great contribution.

Audio equipment probably includes amplifiers, peripherals (including pressure limiters, effects, equalizers, exciters, etc.), speakers (speakers, horns), mixing consoles, sound sources (such as microphones, musical instruments, VCDs, DVDs) display equipment and so on, add up to a set. Among them, the speaker is the sound output devices, speakers, subwoofer, etc., a speaker including high, low, in three kinds of speakers, three but not necessarily three.

The main features of digital audio

1, high signal-to-noise ratio

Digital audio recording form is a binary code, playback only need to determine the "0" or "1". Therefore, the noise of the recording medium has almost no effect on the signal-to-noise ratio of the playback signal. The analog audio recording form is a continuous sound signal, in the process of recording and playback will be affected by such as tape noise, to be superimposed on the sound signal and make the sound quality deterioration, although in the analog audio noise reduction measures, but can not be eliminated fundamentally.

2, low distortion

In the analog audio recording and playback process, the nonlinearity of the magnetic head will be introduced into the distortion, which must be taken to take measures such as AC bias recording, but the distortion still exists. In digital audio, the magnetic head only works in the magnetic saturation or non-magnetic two states, indicating 1 or 0, there is no linear requirement for the magnetic head.

3, good repeatability

Digital audio equipment after many copies and playback, the sound quality will not deteriorate. Traditional analog cassette tape recording, each re-recorded once, the noise recorded on the tape should be increased, resulting in each re-recorded to reduce the signal-to-noise ratio of about 3 dB, the sub-tape is not as good as the master tape, the Sun tape is not as good as the sub-tape, the sound quality degradation by and by.

4, small shake rate

Digital audio playback system due to the role of time-based correction circuit, rotating system, drive system instability will not cause shake, and therefore do not have to ask for the analog recordings of the same precision mechanical systems.

5, adaptable

Digital audio is recorded in binary code, a variety of processing can be carried out as numerical operations, and can not change the hardware, only software operation, easy to control the microcomputer, so adaptable.

6, easy to integrate

Because of the digital, thus facilitating the use of ultra-large-scale integrated circuits, and make the whole machine debugging is convenient, stable performance, high reliability, and convenient for mass production, can reduce costs.