Electronic – How to drive high impedance PA speakers

amplifieraudiopower

As per our design requirement we need to drive PA (public addressing ) speakers whose power rating is only 6W but impedance is 1.3k/3.3k.

So what should be the amplifier rating ?

I want use an audio power amplifier rated for 6W but most of the datasheets for such ICs show this wattage with only 4 Ohm or 8 Ohm speakers.

No datasheet mentions high impedance speakers.

PA speakers are generally mentioned in connection with 100V systems.

Will an amplifier rated for 6W at 8 Ohm or 4 Ohm drive a high impedance speaker?

Length of cable might be 20meters .


Can i use a 70 v, 10w line matching transformer and connect secondary to audio ampifier and primery to pa speakers (in reverse direction ) whose impendence is high. In line matching transformer seconary is named as 4ohm and 8ohm .So if i choose a power audio amplifier for 4 ohm or 8 ohm and connect it to secondary then at primary itself will come at 70v rms and then it may drive our PA speakers whose impendence is high and made for 100v line ?

plz make me correct if i,m missing somthing.

Best Answer

You need a step-up transformer to drive a high impedance speaker with a common PA amplifier. The advantage of using high impedance speakers is the possibility of paralleling them, and use of smaller gauge cable. In your case, having a single speaker at a distance of 20 m from a 6W amplifier, it is not clear to me why a high impedance speaker was required by design.