Amp output volume difference

[Jules@52]

This may be a dumb Question but, I was wondering if two 8ohm speakers running in paralell, off one side of an amp, makes the load 4ohms. Will one 8ohm speaker connected to the other side be quieter than the other two?, with both volume controls set at the same position  I'm asking this because the output is greater at 4ohms but it is running two speakers instead of one. Does this make sense?

[mkfs9]

You are correct , all speakers will be receiving 8ohms so should all be about the same. The two on the 4 omh channel will share the power.

[Mogwix]

 

the "other two" will be louder, mostly since there's two speakers instead of one.

 

if for some reason that's a problem, you can just dial back the attenuator for that channel on the amplifier.

[Jules@52]

Thanks guys, but the amp is rated at more output @4ohms so I thought the two 8ohm speakers in paralell would be putting out more volume than one @8ohms. Electronics and physics are not my strong point

[agedhorse]

You will see gains using 2 speakers per channel from 2 different mechanisms.

 

The first is a doubling of power when you go from 8 ohms to 4 ohms. This occurs on just about all solid state amps. This occurs up until the amp reached rated power at 4 ohms, after that point the 8 ohm speaker may get a little louder as the 8 ohm rating may be a little higher.

 

The second reason is because of constructive coupling, the speakers acoustically combining which occurs primarily (or most effectively) at lower frequencies but is still present well within the midrange in practice.

 

So, the difference will be 3dB from the power doubling and between 1 and 3dB from coupling. You can turn down the attenuated on the channel loaded at 4 ohms to compensate.

[monthlymixcd]

... unless you put the two speakers on the 4-ohm side facing each other, in which case you'd get some serious phase cancellation going on resulting in lower output of that signal, among other things... so don't do that. ;-)