I don't think you need to be set straight as you sound like you are aware of the issues. But I'll lay out some food for thought:
The fixed crossover might mean two different things. One is the normal crossover that all speakers emply to separate the highs from the lows. They are fixed, and usually passive, by design. This has no bearing on the crossover frequency when you are talking about a receiver's bass management capabilities.
Two is that the fixed crossover is actually the crossover frequency the subwoofer uses when it is connected via the .1 input. Not likely though. I've never seen a subwoofer that didn't have an adjustable crossover; whether you want to use the subs crossover or the receiver's is the age old question (9 times out of 10, I would say the correct answer is the receiver's crossover).
satraini said:
I only have speaker cable running to the speaker. My preamp is currently setup for "full range" speakers with no subwoofer.
With this hookup, all bass from any speakers set to small + the LFE are sent to the Def Techs. Is there a woofer in addition to the built-in subwoofer? If so, then that woofer likely is handling the bass+LFE and the subwoofer part is doing nothing. But I don't know these speakers, so its also possible that they are both handling it - giving you double bass.
satraini said:
There is also a terminal for a .1 connection.
The .1 connection is likely there for the case where you want to send it only the LFE and the regular woofer handles only the bass above the crossover. You would need to set Sub=Yes and the Def techs set to small to employ the crossover in the receiver. Some receivers have a double bass feature where bass below the crossover frequency is sent to the mains and the subwoofer, but LFE goes only to the subwoofer. You would have to use the same Sub=Yes, Def Techs=small setting to use that but also tell the receiver to use its double bass feature.
You could use another subwoofer that is separate from the Def Techs and set Sub=yes, Def Techs=small and leave it hooked up the way it is. Doing so would probably only be a benefit if the stand-alone sub were better than the one in the Def Techs or you could get better placement of that sub for optimal sound. Built-in subs are rarely better than stand-alone subs simply because you lose the flexibility of being able to place the sub anywhere it sounds best.
