Description: brand new and high quality Feature: 1.How to choose the power supply? The power supply with the board is very for key, the selected power supply ripple must be small, ripple large power supply will lead to power amplifier bottom noise, there is a current sound.The higher the voltage, the higher the current, and the higher the power output. If you only have 12V 1A, you can have 3-4 inch speakers.If you are above 19V 5A, no problem with 8-10 inches, power must be highly valued.If the voltage is too low and the sound is amplified, it will easily cause sound distortion. If the current is too low and the horn cannot be brought up, the voltage will be pulled down, which will lead to abnormal operation or poor sound quality. It is recommended to use 18V19V24V power supply with current above 5A.If you only have 9V12V or 1A 2A power supply, you can also use it but with low power. When using it, choose the volume close to the maximum, which may cause distortion and affect the sound quality. 2.How to select speakers? About the speaker type: commonly used speakers are generally 4-8 ohms, can be used.Speakers in left and right channels need to be connected to full frequency or medium and high frequency speakers with power between 20W and 100W.Subwoofer speakers cannot be connected to ordinary speakers. Speakers with subwoofer speakers should be connected, with power between 20-100W.The subwoofer horn must have a dive frequency of at least 50Hz. If your speaker power is small, such as between 20W-50W can also be used, the power supply voltage needs to be small, to prevent the loudspeaker burnt after loud, such as choose power below 15V.If you are a 50W-100W speaker, you don'for t have to worry about burning out the horn. You can choose a 12-24V power supply. The higher the voltage you choose, the more sound or power you can output.Speaker power is not easy to exceed 100W, otherwise it will affect the sound quality. 3.Audio input mode: There are two audio input modes for this audio amplifier module: one is Bluetooth-compatible input and the other is AUX input. Bluetooth-compatible mode is preferred.Bluetooth-compatible can be connected in either mode.As long as the Bluetooth-compatible connection is successful, it is Bluetooth-compatible mode, and Bluetooth-compatible mode supports automatic back up.AUX insert is AUX mode when Bluetooth-compatible is disconnected.It should be noted that the Bluetooth-compatible connection of this module is disconnected when using AUX mode. 4.How to adjust the main volume? The MAIN - VOLUME knob is used to adjust the MAIN VOLUME.The right main volume goes up and the left main volume goes down.The master volume affects both the left and right channels and the subwoofer volume. 5.How to adjust the height and of the left and right channels? R&L CHANNEL - knob is for , right-handed enhancement, and left-handed attenuation.When the knob is in the right-most position, it does not enhance or attenuate the . The R&L CHANNEL - TREBLE knob is used to control the TREBLE, with right-handed TREBLE enhancement and left-handed TREBLE attenuation.When the knob is in the middle, it does not enhance or attenuate the treble. Note when adjusting high and low sounds: when the TREBLE or sounds are right-rotated to near maximum, if the sound distortion is distorted, the gain of the TREBLE or sounds is too large. It is necessary to turn the TREBLE or knob to the left to lower the gain or turn the MAIN-VOLUME knob on the right to the left to reduce the total VOLUME. 6.How to adjust the subwoofer? SUBWOOFER - VOLUME controls the VOLUME of the SUBWOOFER.The right-handed volume goes up and the left-handed volume goes down. The SUBWOOFER - FREQ knob controls the cutoff frequency of the SUBWOOFER.The right frequency increases and the left frequency decreases.The frequency adjustment range is 20HZ-200Hz. 7.It's ok to have a small voice, but after the voice becomes louder, there will be the phenomenon of sound turbidity. The sound is distorted, please turn down the total volume or change the adapter to a higher voltage level. 8.It's ok to have a small voice, but when the voice gets louder, there will be the phenomenon of sound lag. If the input power is insufficient and the power is protected by its own intermittent power failure, please replace the power with a more powerful one.Or the power is too big, the power amplifier heating seriously, appeared the heat for protection situation, reduce the power use or strengthen the heat dissipation. 9.What factors are associated with sound quality? The quality of sound is not only related to the power amplifier module, but also to the power supply, sound source and the whole sound system.Basically every link of the sound system will affect the sound quality, among which the main link is the audio transmission line, audio power supply, tone circuit, amplifier circuit, speakers and