Those look real fancy but that's not what I need at all.
Let me describe the situation differently:
Let's say you have a home amplifier/receiver, a CD player, and a cassette deck. You want to make a cassette copy of a CD. The CD player is, of course, connected to the "CD In" left and right RCA inputs on the amp. The cassette deck is connected to the "TAPE" outs (forget the ins for now). To record the CD, your start it playing, put a cassette in record and adjust the levels on the cassette deck.
Now let's assume your cassette deck's record level knobs are stuck, say, on "5" out of 10. What could you put between the amp and the cassette deck to adjust the levels?
This is my question. Just substitute the active (powered) speakers for the cassette deck.