When connecting an amplifier to a speaker it is important to
match the impedance of the amplifier to the speaker for maximum power transfer:
On the circuit below we have an 8 ohm amplifier connected to
two 4 ohms speaker in series to get 8 ohms (4+4) and therefore the amplifier
impedance is equal to the speaker impedance.
If you don’t observe this principle then you will overload
the amplifier and eventually it will blow.
