Sorry, but you wouldn't gain any efficiency.
If you're talking about a filter that comes before the amplifier, you'd gain about 1 dB of amplifier headroom by relieving it of having to reproduce the bass region at full power. If the filter comes after the amplifier, then it depends on the amplifier type but at most you'd gain about 1 dB of headroom.
Duke
If you're talking about a filter that comes before the amplifier, you'd gain about 1 dB of amplifier headroom by relieving it of having to reproduce the bass region at full power. If the filter comes after the amplifier, then it depends on the amplifier type but at most you'd gain about 1 dB of headroom.
Duke