ElectrO_90 :
You should list the brand/model of both the amp and the sub.
The reason for this, cheap brands just lie when they use advertising.
So if you can list it, people could give you more reasonable advice and not some sarchastic comment as USAFRet has said "If I put 10 gallons into a 24 gallon gas tank, will it still run?
Or do I have to use the whole 24 gallon capacity? "
That helps no one, but he is normally not this obtuse to Computer related questions.
The number associated with the speaker(s) "1200" is not the same thing as the number associated with the amp "1000".
The speaker number is (theoretical) capacity (gas tank size)
The number associated with the amp is , (in theory) how much it can output.
You can run a "1200w speaker" with a 10 watt amp.