Using subwoofers HF crossover

I am gonna be demo-ing new speakers within a week, if that fails to give me a substantial improvement I am gonna keep my Thiels and consider purchasing a subwoofer for my system (Thiel CS1.0, Marantz 7200 amp, 6004 cd player in a 12x14 mancave room), which I know will give my bass-shy Thiels and system the needed change. Some subs have a LF input and output that I can loop my signal from the pre-amp stage into to sub and back to the amp. Using this crossover prevents the main amp from using its power to drive my main speakers for frequencies below the selected crossover point. My question is, will this advantage outweigh the possible degradation of the source signal and lose potential sound quality in the mid's and high's? I ask this because in selecting a Sub some have this as a feature others do not. Some people say just run the sub in conjunction with the main system. set the subs low frequency pass to match the rolloff of your mains and let the main amp and speakers do there normal work.
Hi Raya,

Other than the obvious answer -- try it -- i will say i used to run my speakers thru the sub crossover...when i had tiny bookshelves. But i have stopped doing that a long, long time ago as i have moved up to full-range speakers. In your case, i am not familiar with the 1.0, only the older Thiel 1.2 from the early '90s which i know pretty well having auditioned many, many times.

In the case of that speaker, i would still be comfortable running it full range and running the sub in parallel and trying to blend a, not using the internal sub crossover...probably cutting off the sub at 45hz-50hz with a slow rolloff and seeing how it goes.

good luck, enjoy your excellent system and pls keep us posted!