The equalizer block cascades 7 bands of equalizer to each channel to tailor the frequency characteristics of embedded speaker system according to user preferences and to emulate environment sound.
The equalizer module cascades 7 equalizer bands to each channel to adjust the frequency characteristics of the embedded speaker system according to user preferences and simulate ambient sound.
The 7 bands equalizer includes two high pass filters, three band pass filters, one low pass filter and one biquad filter.
The 7-band equalizer consists of two high-pass filters, three band-pass filters, a low-pass filter and a biquad filter.
One high pass filter cascaded in the front end is used to drop low frequency tone, The tone has a large amplitude and may damage a mini speaker.
A high-pass filter cascaded on the front end is used to reduce low-frequency tones, which are loud and can damage the mini-speaker.
The high pass filter can be used to adjust Treble strength with gain control.
A high-pass filter can be used to adjust the treble intensity via the gain control.
One low pass filter with gain control can adjust the Bass strength.
A low-pass filter with gain control adjusts the bass intensity.
Three bands of band pass filters are used to emulate environment sounds, e.g., ‘Pub’, ‘Live’, ‘Rock’,… etc..
Use three bandpass filters to simulate ambient sounds such as 'Pub', 'Live', 'Rock' and more.
The gain, center frequency and bandwidth of each filter are all programmable. One biquad filter can switch to high-pass, low-pass or band-pass filter by register settings.
The gain, center frequency and bandwidth of each filter are programmable. A biquad filter can be switched to high-pass, low-pass or band-pass filter by register setting.
The role of an equalizer is to adjust the strength of signals of different frequencies.
Sound as a wave has three elements: amplitude, frequency, and phase. The amplitude determines the size of the sound, and the frequency determines the pitch of the sound. The actual sound is often not a single frequency wave, but a superposition of waves of various frequencies, thus forming a unique sound.
y = Asin(wt+fi)+A0 (single-frequency sound wave description)
y = A1sin(w1t+fi1) + A2sin(w2t+fi2) + ... (actual sound wave description)
The difference in sound is the sound of different frequencies Signals have different strengths. The equalizer is based on this principle to achieve.
The equalizer can automatically separate signals of different frequencies, and take different degrees of amplification or reduction, thereby changing the effect of the sound. At present, the equalizer is implemented directly by hardware (such as the hardware Equalizer of SAA7709), and also implemented by software (such as Qian Qian Mute). Of course, in principle, there can be equalizers that process analog signals, and there can also be equalizers that process digital signals.
Equalizers generally divide the frequency range (20Hz-20KHz) that people can hear into multiple frequency bands, and amplify or reduce (gain or negative gain) the acoustic signals of different frequency bands to varying degrees. Such as thousands of silences are divided into 10 frequency bands. The hardware equalizer of SAA7709 has 20 hardware units. When the 2X10 mode is adopted, the sound signal can be divided into 10 frequency bands (section), and when the 4x5 mode is adopted, it can be divided into 5 frequency bands (section).