Expand

Refers to whether the speaker supports multi-channel simultaneous input, whether there is an output interface for passive surround speakers, whether it has a USB input function, etc. The number of subwoofers that can be connected to external surround speakers is also one of the criteria to measure the expansion performance. The interfaces of ordinary multimedia speakers mainly include analog interfaces and USB interfaces. Others, such as optical fiber interfaces and innovative digital interfaces, are not very common.

Sound effect

The more common hardware 3D sound effects technologies include SRS, APX, Spatializer 3D, Q-SOUND, Virtaul Dolby and Ymersion. Although they have different implementation methods, they can all make people feel obvious three-dimensional sound field effects. The first three are more common. What they use is the Extended Stereo theory, which is to additionally process the sound signal through the circuit, so that the listener feels that the sound image direction is extended to the outside of the two speakers, so as to expand the sound image and make people have space sense and three-dimensionality, resulting in a wider stereo effect. In addition, there are two sound enhancement technologies: active electromechanical servo technology (essentially using the Helmholtz resonance principle), BBE high-definition plateau sound reproduction system technology and “phase fax” technology, which also have a certain effect on improving sound quality. For multimedia speakers, SRS and BBE technologies are easier to implement and have good effects, which can effectively improve the performance of speakers.

Tone

Refers to a signal with a specific and usually stable wavelength (pitch), colloquially speaking, the tone of sound. It mainly depends on the wavelength. For a sound with a short wavelength, the human ear responds with a high pitch, while for a sound with a long wavelength, the human ear responds with a low pitch. The change in pitch with wavelength is essentially logarithmic. Different instruments play the same note, although the timbre is different, but their pitch is the same, that is, the fundamental wave of the sound is the same.

Timbre

The perception of sound quality is also the characteristic quality of one sound that distinguishes it from another. When different instruments play the same tone, their timbre can be quite different. This is because their fundamental waves are the same, but the harmonic components are quite different. Therefore, the timbre not only depends on the fundamental wave, but also is closely related to the harmonics that are an integral part of the fundamental wave, which makes each musical instrument and each person have a different timbre, but the actual description is more subjective and may feel Rather mysterious.

Dynamic

The ratio of the strongest to the weakest in a sound, expressed in dB. For example, a band has a dynamic range of 90dB, which means the weakest part has 90dB less power than the loudest part. Dynamic range is the ratio of power and has nothing to do with the absolute level of the sound. As mentioned earlier, the dynamic range of various sounds in nature is also very variable. The general speech signal is only about 20-45dB, and the dynamic range of some symphonies can reach 30-130dB or higher. However, due to some limitations, the dynamic range of the sound system rarely reaches the dynamic range of the band. The inherent noise of the recording device determines the weakest sound that can be recorded, while the maximum signal capacity (distortion level) of the system limits the strongest sound. Generally, the dynamic range of the sound signal is set to 100dB, so the dynamic range of the audio equipment can reach 100dB, which is very good.

Total harmonics

Refers to the extra harmonic components of the output signal caused by the nonlinear components than the input signal when the audio signal source passes through the power amplifier. Harmonic distortion is caused by the fact that the system is not completely linear, and we express it as a percentage of the root mean square of the newly added total harmonic component to the rms value of the original signal.