This doesn't really have anything to do with my 990, but I figured the 990 forum would be the best place to post it.

Last year I got the 990/7125/LFM-1+ combo.
At that time I had two stereo speakers, B&W DM603.
I went onto eBay and got a B&W CC6 S2 Center Speaker, and two B&W DS6 Surround Speakers.
Due to my hectic schedule, I've only watched a handful of DVD since I got this setup.
However, there is an anomaly that I've noticed that I need some advice on.

When I'm watching a DVD (or DD 5.1 from cable box), I can change sound modes between Stereo and DD with the remote.
While in Stereo Mode, the voices (center) are played from the 2 stereo speakers (center speaker is off), and the voices have good
quality sound and clear high frequencies.
While in DD or DTS (when the center speaker is used) the voices sound "dull" and somewhat "muted".

I wasn't sure if it was a problem with the CC6 speaker or my MIT T2 BiWire cable.
While the BiWire cable was connected to the speaker, I disconnected the "low frequency" red&back cables; this only left the "high frequency" connected.
After I did this, I listened to the tweeter on the CC6, and I could hardly hear anything. So I thought either the tweeter or crossover on the CC6 went bad.
Then I decided to hook the BiWire "low frequency" cables up again, but this time I placed the binding-post connector on the back of the CC6 (this is used when you don't have BiWire cables).
After I did that, there was sound coming from the tweeter, but still did not sound as clear as it should.

I'm not sure what all else to try, and I don't know if the problem is with the speaker or the cable.

In any event, I'm looking to buy a "new" center speaker to replace the CC6, so I can test it with that.
The only problem is that the center speaker cut-out space in my Entertainment Center cabinet is only 18" wide, and the CC6 is 17.7".

Can anyone give advice on a High Quality (biwireable) center speaker that could fit in that 18"W space?
I've looked the new B&Ws and Monitor Audio, but all wider than 18".

Thanks.