Created: Sep 08, 2015
No description available.
The sound system for car vehicles has been around for almost the same period of time the car was invented. It helps the driver and the passengers enjoy the entire trip. This reference design is an example of a simple car sound system that consists of two stereo speakers located at the front and rear part of the car. The goal of this reference design is to provide a low-cost yet high fidelity car sound system. The circuit is made up of a stereo passive baxandall 2-band equalizer, four buffers, four power amplifiers, and four speakers. The circuit is designed to be simple and can be powered directly by the car’s 12V battery.
The operation of the circuit starts at the audio source of the sound system. The signal from the left and right channel of the source is buffered or amplified by the two operational amplifiers U2a and U2c. The amplification depends on the gain set by R2 and R11 potentiometers. After boosting the audio signal, it will now pass to the 2-band baxandall equalizer. The inability of the speaker to respond flatly across the audio spectrum is compensated by the equalizer by boosting or cutting the high or low frequency components of the audio signal. After equalizing the frequency characteristic of the audio signal, it will be buffered by U2b and U2d operational amplifiers.
The potentiometers R19 and R20 control the master volume of the front and rear power amplifiers. The signals passing through these potentiometers are buffered again by four buffers, two for the two front power amplifiers and another two for the two rear power amplifiers. The power amplifier used in this circuit has a power output of 55W at 0.5% total harmonic distortion (THD) and four-ohm load. The maximum power it can give at 10% THD is around 70W. The connection between the power amplifier and the speaker is supported by the TE Connectivity 1217861-1 tab and 41274 receptacle crimp. The crimp is insulated by the TE Connectivity 1-170823-5 sleeve in order to protect the contacts between the power amplifier and the speaker.