TDA2030 is a widely used 14W audio power amplifier monolithic integrated circuit in Pentawatt [ package, intended for use as a low-frequency class AB amplifier. However, some home theater prototype came with TDA2030 design has a problem of low volume. There are ways to increase the subwoofer performance that uses TDA2030A design.
Updated Schematic TDA2030 Subwoofer Amplifier adding voltage regulator 7815 and 7915 for supply voltage subwoofer filter:
TDA2030 Subwoofer Amplifier Circuit Diagram
Increase subwoofer performance By Adding subwoofer filter 4558 and changing resistor
Some circuit board designs usually soldered a 10K or less value resistor in place of default 22K recommended by the 2030 designers. Use 22K or more instead of 10K to increase the gain thereby reducing the bypass of input to ground. (input should be noise free) However, the increasing gain over the recommended value may result in overheating the IC unless you have best heat control methods. And adding subwoofer filter 4558 can filtering subwoofer audio signal input.
Layout PCB Subwoofer Amplifier TDA2030 complete voltage regulator 7815 and 7915 for subwoofer filter 4558: