bad sound with hdmi

The short question is that when I use hdmi to get the digital sound and based on the device and the program material I get no center speaker sound or low dialog sound(maybe the same thing).

I have 3 sources of video and sound:
1. comcast dvr dcx3400 - hdmi and optical/coax
2. logitech google tv - hdmi and optical
3. lg bd player bd 390 - hdmi and optical/coax

receiver/amplifier
sony str-k740p - 6.1 sound

Every time I direct connect the digital audio thru either optical or coax I get good sound whether 5.1 or stereo program material.

When I connect the sound from either the logitech hdmi pass thru or a hdmi switch some of the program material will get the no center sound or low dialog symptom.

The hmdi switch is:

4X1 HDMI® Switcher w/ Toslink & Digital Coaxial Port (Rev.2) w/ 3D support.

http://www.monoprice.com/products/product.asp?c_id=101&cp_id=10110&cs_id=1011002&p_id=5557&seq=1&format=2

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So the question is:
1. Should I always just direct connect the sound and thereby add that extra step for switching sources.
2. Get a new receiver with hdmi switching because my sony is so old it is having trouble decoding.

thanks
bob

That seems to the conclusion I am coming to.
Except the logitech google tv exhibits the same problems.

What problems have you had with the monoprice switches?