While doing what you are proposing may increase the longevity of the amplifier, chances are you'll get less volume, not more, unless the amp is pretty much unable to function in a reasonable manner with the 4 ohm load.
Each of the series connected speakers would see half of the voltage that is being put out by the amp at any instant of time, resulting in each speaker receiving 1/4 of the amount of power that it would receive if the full output voltage of the amp at that instant were applied across it. So the total power delivered to both speakers (in each channel) would be only 1/2 as much as it would be if the full output voltage of the amp were applied across a single speaker.
The only way in which a volume increase would result is if the maximum output voltage that the amp can provide into 4 ohms (and that it can sustain, for some amount of time that depends on the kind of music you are listening to) is much less than what it can provide into 8 ohms, which would be indicative of a weak design.
I am assuming, btw, that you are referring to a solid state amp, not a tube amp.
Also, btw, keep in mind that for good sonic results series connected speakers should, in general, be identical models.
Regards,
-- Al
Each of the series connected speakers would see half of the voltage that is being put out by the amp at any instant of time, resulting in each speaker receiving 1/4 of the amount of power that it would receive if the full output voltage of the amp at that instant were applied across it. So the total power delivered to both speakers (in each channel) would be only 1/2 as much as it would be if the full output voltage of the amp were applied across a single speaker.
The only way in which a volume increase would result is if the maximum output voltage that the amp can provide into 4 ohms (and that it can sustain, for some amount of time that depends on the kind of music you are listening to) is much less than what it can provide into 8 ohms, which would be indicative of a weak design.
I am assuming, btw, that you are referring to a solid state amp, not a tube amp.
Also, btw, keep in mind that for good sonic results series connected speakers should, in general, be identical models.
Regards,
-- Al