Hey guys. My family and I are moving to a two-story house and am planning to set up a multimedia home theater with Dolby Digital. And mount a big screen! It will be awesome!! I want to hook up 4 signal sources to 2 TV panels and control them. The 4 sources will be my old laptop (no hdmi output), Blu-ray player, cable TV, and PC (video card has HDMI). Question is: can I use hdmi matrix switchers and converters for non-hdmi signals? Do matrix switchers support multi-channel Dolby Digital audio? Thanks for the input!

The old laptop with no HDMI can be resolved pretty easy with a VGA to HDMI active adapter. They're sold on Newegg.
 
http://www.newegg.com/Pro..._-15-158-397-_-Product

Most Matrix Switchers will "Pass" Dolby Digital and DTS audio signals.  Good, modern, expensive ones will support the HD audio formats.  Do you have a budget range?  How are you planning on controlling it.  The good ones often need custom programming and a controller and touch panel.  It really depends how deep you want to go down this rabbit hole.

 
Moving to General Hardware.

Thank you, Tweaked. You wrote:

Tweaked
Most Matrix Switchers will "Pass" Dolby Digital and DTS audio signals.  Good, modern, expensive ones will support the HD audio formats.  Do you have a budget range?  How are you planning on controlling it.  The good ones often need custom programming and a controller and touch panel.  It really depends how deep you want to go down this rabbit hole.

My budget is about $1700. I found some devices here
I’m looking at A-NeuVideo ANI-44C5CT ($1475) and TV One 1T-MX-6344 ($1295). These switchers are 4x4. Anyone familiar with these two brands/models?

Between those two, I would say go with the A-NeuVideo.  It has HDBase-T output as well as HDMI which would give you more flexibility and allow you to transport the video more than 50 ft if needed.  They both offer you IR and RS-232 control.  However, if you don't have a control system, I would say use IR.  Although, there is no good (easy) way to track IR conditions so there is significant potential to get out of sync with the switcher and get frustrated.  My recommendation would be something like the Marantz SR7010 AVR.  It offers so much more than either of those Matrix Switchers.  You get an 8x2+1 HDMI Switcher with 4k HDMI 2.0 and HDCP 2.2 compatibility, HDR, HD Audio processing, 3D audio processing, 9 channels of amplification, 2 sub EQ channels, Audessey XT32 processing, Bluetooth, Airplay, IR/RS-232/IP Control...  And the list goes on.  Not to mention that it is $1k off right now.  
 
https://www.amazon.com/Ma...luetooth/dp/B014MWT9YY