I tried some different tests with the B&W CC6 S2.

Test group A was without the binding-post jumpers connected on the rear of the speaker's bi-wire connections
Test group B does have the jumpers installed on the binding-posts.

All test were does with MIT T2 BiWire cable.

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Group A (no jumpers)

Test 1)
Speaker connected to biwire cable. The High Frequency cable to the HF input and Low Freq cable to the LF input.
Sound can be heard from both the woofer and tweeter.
Sound has a "muted" or "muffled" sound to it.

Test 2)
Removed the HF cable, just leaving the LF cable connected to the LF input.
Only hear low freq sound coming from woofer (tweeter no sound).

Test 3)
Removed the LF cable and reconnected the HF cable to the HF input.
Almost no sound could be heard from the tweeter.

I then decided to try the HF cable on the LF input, and LF cable on HF input.

Test 4)
Removed all cables and connected the HF cable to the LF input.
I only heard low freq sound from woofer as in Test 2.

Test 5)
Removed all cables and connected the LF cable to the HF input.
I got almost no sound from the tweeter, just like Test 3.

Test 6)
Removed all cables, then connected the LF cable back to the LF input.
I got the results as in Test 2 and 4.
Then (while the audio was playing) connected the HF cable to the HF input.
I could then hear high freq sound coming from the tweeter, as in test 1, but overall sound still sounded muffled.

Those 6 tests in Group A told me that with the HF cable connected to the HF input, and LF cable to the LF input, that
sound would be heard from both tweeter and woofer. But removed the LF cable with just the HF connected and no sound would be
heard from the tweeter. Also, swapping the LF and HF cables to the opposite inputs had the same results.

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In Group B in installed the binding post jumper between the HF/LF Black and the HF/LF Red inputs on the back of the speaker.

Test 1)
Speaker has binding post jumpers installed. Connected the LF cable to LF input and HF cable to HF input.
Sound could be heard from both woofer and tweeter (just like group A, test 1), but sound was louder and a litter clearer.

Test 2)
Removed the HF cables, leaving the LF cable connected to the LF input (which has jumper to HF connected).
Sound could be heard from woofer and tweeter, but not as good sound as in test 1.

Test 3)
Removed LF cable and connected HF cable to HF input (with jumpers connected to LF).
Got same results as in Test 2.

Test 4&5)
Same procedure as in Test 4 and 5 in Group A, expect for binding post jumper installed.
I got the same results as in test 2 and 3 in group B

The Group B tests told me that with the binding post jumpers installed, that I would get the same sound
no matter if the HF or LF cable was connected. It only sounded louder and clearer when both HF and LF cables were connected together.


So in conclusion (if you've made it this far), having the LF and HF cables connected to the speaker, while at the
same time having the binding post jumpers connected, give a slightly better sound than just having the LH & HF
connected and not having the jumpers connected.
Still overall, I'm not too happy with the sound produced by the center, as opposed to my 603 mains.
Voices from the 603s (when in 2ch downmix) are better quality than from the CC6 S2 (when in DD/DTS).
I guess I may need to eBay a new B&W center from the HTM series.