Actually as per our design requirement we want to drive PA (public addressing ) speakers whose power rating is only 6W but impedance is 1.3k/3.3k.high impedance speakers i mean to say.so what should be the amplifier rating ? i want use some audio power amplifier whose rating will be 6W but most of datasheet showing this wattage with only 4 ohm or 8ohm.but no ic is talking about high Impedance .PA speakers generally talking about 100v line .will these amplifier whose rating is 6w at 8 ohm or 4ohm will drive this high impedance speakers? length of cable might be 20mtr .