Just one more point..... if you want to experiment:
BEcause Caps of different values charge and discharge differnetly,
Generally smaller are faster.... by connecting differnt valued caps in parallel will give a very discharge charateristic which can give better results. For expamle.... 2 x 4700uF in parallel is better than 1x 10.000uF . Manufacturer dont tdo that to save money and board space....
I use this method in all my designs in audio equipment.... and it really works!!!
remember, speakers is like a motor.... it needs power and instantaneous acceleration adn braking!!!!! and the impedance is 2-16 Ohm only so it is a heafty load too!!!