Thanks for the replies,
I was trying to use what still works for my friend, that is why I was thinking for now just to get a good receiver as long as we can find one with a high enough cut off to not damage those bose speakers.
I was thinking he can upgrade speakers later ect.... I did not want him to have to spend a lot of money on buying everything new because I feel if I tell him that he will probally just go and buy a new acousticmass mass on ebay for $100 and he will be back in business. I am trying to get him out of the BOSE trap, and show him going this route will allow you can expand as time goes on and build something solid!
I will see if anyone else chimes in regarding the cut off freq
Thanks again guys
I have dug some information up for you.
The bass module goes up to 200 Hz, but the cubes cut off at 280 Hz. That is the famous Bose gap.
Now I don't know the order of the cut off, but my guess is fourth order. That would put those cubes down 24 db at 140 Hz, they would only be 12 db down at 140 Hz second order which is the high pass slope of a receiver. They would not be 24 db down until 70 Hz with a second order slope.
So if you do preserve his cubes, you will need a receiver with pre outs, separate amps for the cubes and adjustable fourth order active crossovers, that you can split the crossover points. That will be a huge bill and not worth it.
So he needs another Acoustimass, have his fixed, or start with a system from scratch.
You can start to see why those Bose systems costs what they do, and again they are not worth it.
OK, I have found further information which I believe to be reliable. The bass module is a seventh order bandpass. So this driver will roll off steeply of it own accord. However to stop the port radiating HF from the drivers and limit amp power, there is a 6 db low pass filter at around 200 Hz.
The cubes start to roll off around 500 Hz, first order, as I guess Bose has not heard of BSC!
Then to stop damage there is steep roll off around three hundred Hz, almost certainly fourth order.
So you won't reproduce that with a receiver.
You can read all about it here.