ONE, TWO, THREE, LIFT

Why is it sound engineers?
When there’s a gig to do
And they have to test the system
Say one two, one two, one two
And at the end of the gig
When there’s packing up to do
They don’t have any testing
But they’re nowhere in view
I think sound engineers
Can only count up to two
Because if they counted up to three
There would be heavy lifting to do