I have found a
better instruction manual here. Not good, but better. This is not the one on the Sony receiver site.
Strangely they recommend setting all speakers to large, unless they basically complain.
{Select the size you want. Large: If you connect large speakers that will effectively reproduce bass frequencies, select [Large]. Select [Large] usually. Small: If the sound is distorted, or you hear a lack of surround effects when using multi channel surround sound, select [Small]. You can activate the bass redirection circuitry and output the bass frequencies of each channel from the subwoofer or other [Large] speakers.}
There is no mention of being able to send bass to the sub also, but I would not bet that it does not. The OP can check that by setting the speakers to large as Sony recommends and see if there is output from the sub.
Certainly it looks as if Sony have little confidence in their bass management it seems.
If there is output from the sub with the above recommendation please let us know.
This is possibly not as crazy as it sounds, as I am more and more convinced that keeping capable speakers large and sharing bass duties with the sub is actually the best way to go in most cases. To cross speakers over properly you need to design sub and speakers as a unit to perform optimally in partnership. Design the speakers to properly perform with a crossover that is second order LR high pass and fourth order LR low pass. The vast majority of speakers do not meet that criterion and my recent endeavors tell me that is actually a serious problem.
