audio set-up for beginners [continued]

[aprilboyidol]

what happens if you run an 8 ohm speaker with an amp with a 4 ohm output

[CVT]

what happens if you run an 8 ohm speaker with an amp with a 4 ohm output

Not a maximum power transfer...

Assuming 12v, power on the speaker will be 64/8 or 8W... Vs 4 ohm speaker with power of 36/4 or 9W...

Should be "okay"

[markygy]

what happens if you run an 8 ohm speaker with an amp with a 4 ohm output

The 8ohm speaker will recieve half of the rated power output the amp gives *4ohms. If for example the amp gives 100watts *4ohms, a 8ohm speaker will only get 50watts. This is because a 8ohm speaker has double the RESISTANCE of a 4ohm speaker.