Frequency range and frequency response
Time:March 11, 2025
Views:41
The former refers to the range between the lowest effective playback frequency and the highest effective playback frequency that an audio system can reproduce; the latter refers to the phenomenon where, when an audio signal output at a constant voltage is connected to the system, the sound pressure produced by the speaker increases or attenuates with changes in frequency, and the phase changes with frequency. This correlated change relationship (change amount) between sound pressure and phase with frequency is called frequency response, with units of decibels (Db).
The frequency response curve of an audio system is commonly depicted with power represented on the vertical axis using a decibel scale and frequency represented on the horizontal axis using a logarithmic scale. When the sound power is 3dB below normal power, this power point is referred to as the high-frequency cutoff point and low-frequency cutoff point of the frequency response. The frequencies between the high-frequency cutoff point and low-frequency cutoff point represent the frequency response of the device; the curves representing the variation of sound pressure and phase lag with frequency are called "amplitude frequency response" and "phase frequency response", collectively referred to as "frequency response".
This is an important indicator for assessing the performance of a loudspeaker. It has a direct relationship with the loudspeaker's performance and price. The lower the decibel value, the flatter the frequency response curve of the loudspeaker, the less distortion it has, and the higher its performance. For example, a loudspeaker's frequency response is 60Hz~18kHz +/-3dB. These two concepts are sometimes not distinguished and are collectively referred to as frequency response.
Theoretically, a frequency response ranging from 20 to 20,000 Hz is sufficient. Although sounds below 20 Hz are inaudible, they can be detected by other human sensory organs, which means that the so-called bass dynamics can be felt. Therefore, in order to perfectly reproduce various musical instruments and speech signals, an amplifier must achieve high fidelity to reproduce all harmonics of the tone. Therefore, the frequency band of the amplifier should be extended, with the lower limit extended below 20 Hz and the upper limit raised above 20,000 Hz. The representation methods for the frequency response of signal sources (such as radio heads, record players, and compact disc players) vary.
For example, the frequency response of FM stereo broadcasting specified by the European Broadcasting Union is +2dB from 40 to 15000Hz. The minimum frequency response specification for recording decks specified by the International Electrotechnical Commission is +2.5 to +4.5dB from 40 to 12500Hz (for regular tapes). The actual achievable specifications are significantly higher than these values. The upper limit of the frequency response of a CD player is 20000Hz, and the low-frequency end can be made very low, only a few hertz. This is one of the reasons why CD players have good playback quality.
However, the harmonic components that constitute sound are very complex. It is not true that a wider frequency range makes the sound more pleasant. Nevertheless, this is still basically correct for mid-to-low-end multimedia speakers. When marking frequency response, we usually see two terms: "system frequency response" and "amplifier frequency response". It is important to know that the "system frequency response" is always narrower than the "amplifier frequency response". Therefore, marking only the "amplifier frequency response" is meaningless and is only used to deceive some uninformed consumers.
Nowadays, speaker manufacturers generally label the system frequency response with an overly wide range. While the high-frequency part is not that far off, the labeling of the bass end is extremely unrealistic. Even foreign brand HiFi (high-fidelity) speakers only label around 40-50Hz, yet domestic wooden ordinary speakers priced at two or three hundred yuan dare to label this data. It's really ridiculous! So I advise everyone to listen to the low-frequency sound with their own ears and not to easily believe the values on the promotional leaflets. The music in multimedia speakers mainly consists of music from MP3 or CD playback, songs, game sound effects, background music, and human voices and environmental sound effects in movies. These sounds are mostly in the mid-to-high frequency range, so when selecting multimedia speakers, you should pay more attention to its performance ability in the mid-to-high frequency range, rather than the low-frequency range. If you really pursue cinema-like effects, then a powerful subwoofer can definitely meet your needs.
The frequency response curve of an audio system is commonly depicted with power represented on the vertical axis using a decibel scale and frequency represented on the horizontal axis using a logarithmic scale. When the sound power is 3dB below normal power, this power point is referred to as the high-frequency cutoff point and low-frequency cutoff point of the frequency response. The frequencies between the high-frequency cutoff point and low-frequency cutoff point represent the frequency response of the device; the curves representing the variation of sound pressure and phase lag with frequency are called "amplitude frequency response" and "phase frequency response", collectively referred to as "frequency response".
This is an important indicator for assessing the performance of a loudspeaker. It has a direct relationship with the loudspeaker's performance and price. The lower the decibel value, the flatter the frequency response curve of the loudspeaker, the less distortion it has, and the higher its performance. For example, a loudspeaker's frequency response is 60Hz~18kHz +/-3dB. These two concepts are sometimes not distinguished and are collectively referred to as frequency response.
Theoretically, a frequency response ranging from 20 to 20,000 Hz is sufficient. Although sounds below 20 Hz are inaudible, they can be detected by other human sensory organs, which means that the so-called bass dynamics can be felt. Therefore, in order to perfectly reproduce various musical instruments and speech signals, an amplifier must achieve high fidelity to reproduce all harmonics of the tone. Therefore, the frequency band of the amplifier should be extended, with the lower limit extended below 20 Hz and the upper limit raised above 20,000 Hz. The representation methods for the frequency response of signal sources (such as radio heads, record players, and compact disc players) vary.
For example, the frequency response of FM stereo broadcasting specified by the European Broadcasting Union is +2dB from 40 to 15000Hz. The minimum frequency response specification for recording decks specified by the International Electrotechnical Commission is +2.5 to +4.5dB from 40 to 12500Hz (for regular tapes). The actual achievable specifications are significantly higher than these values. The upper limit of the frequency response of a CD player is 20000Hz, and the low-frequency end can be made very low, only a few hertz. This is one of the reasons why CD players have good playback quality.
However, the harmonic components that constitute sound are very complex. It is not true that a wider frequency range makes the sound more pleasant. Nevertheless, this is still basically correct for mid-to-low-end multimedia speakers. When marking frequency response, we usually see two terms: "system frequency response" and "amplifier frequency response". It is important to know that the "system frequency response" is always narrower than the "amplifier frequency response". Therefore, marking only the "amplifier frequency response" is meaningless and is only used to deceive some uninformed consumers.
Nowadays, speaker manufacturers generally label the system frequency response with an overly wide range. While the high-frequency part is not that far off, the labeling of the bass end is extremely unrealistic. Even foreign brand HiFi (high-fidelity) speakers only label around 40-50Hz, yet domestic wooden ordinary speakers priced at two or three hundred yuan dare to label this data. It's really ridiculous! So I advise everyone to listen to the low-frequency sound with their own ears and not to easily believe the values on the promotional leaflets. The music in multimedia speakers mainly consists of music from MP3 or CD playback, songs, game sound effects, background music, and human voices and environmental sound effects in movies. These sounds are mostly in the mid-to-high frequency range, so when selecting multimedia speakers, you should pay more attention to its performance ability in the mid-to-high frequency range, rather than the low-frequency range. If you really pursue cinema-like effects, then a powerful subwoofer can definitely meet your needs.
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