The Martin Logans cover more of the highs, while the B&Ws cover more of the midrange. With music, the B&Ws sound more realistic, but with movies, the Martin Logans sound better. I was told that matching manufacturers is key to maintain the same tonal character. If I don't, will there be an impact to movies and music? Any feedback on these speakers in general and/or matching manufactures would be very helpful. I am willing to go listen to other speakers that you suggest.
My first response is that using in-ceiling speakers with an ear-level center-channel speaker is not a great idea, no matter what the brand. The entire front soundstage should come from the front, not from the front in the middle and from above on the left and right. I really hope you can find a way to use standalone speakers for the front left and right channels.
If you can do that, I strongly recommend B&Ws for the front left and right. It's true that speakers from the same manufacturer have a much better chance of matching tonally, which is critical for creating a seamless soundstage. Also, I would get the B&W model that most closely matches the CM2—B&W recommends the CM9, shown above with the CM2.
In-ceiling speakers are not so bad for the surrounds, since the surround soundfield is supposed to be diffuse anyway. I would stick with B&W to maintain a consistent front-to-back tonal quality.
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