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.
On the other hand if you two 8 ohms speakers and an amplifier with 4 ohms impedance then you will need to connect the speaker in parallel to achieve the 4 ohms impedance of the amplifier for maximum power transfer.
See the arrangement on the diagram below:
Thanks you guys
See you in the next class