Depends upon the size and location of the capacitor.
On the power input to the radio, large uf capacitors filter out annoying noise and power spikes that can work its way into the amplifier. Upper end radios don't have that much of a problem as they have better filtering.
In the olden days of vacuum tube amplifiers, across speaker terminals, small uf capacitors boost the bass by shunting some of the high frequencies around the speaker. Don't do it in today's amplifiers. You could cause ultrasonic oscillations in the output stages of the amplifer - destroying the amp.
On the power input to the radio, large uf capacitors filter out annoying noise and power spikes that can work its way into the amplifier. Upper end radios don't have that much of a problem as they have better filtering.
In the olden days of vacuum tube amplifiers, across speaker terminals, small uf capacitors boost the bass by shunting some of the high frequencies around the speaker. Don't do it in today's amplifiers. You could cause ultrasonic oscillations in the output stages of the amplifer - destroying the amp.