that hdmi switch is the same one still sold by monoprice here
http://www.monoprice.com/Product/?c_id=101&cp_id=10110&cs_id=1011002&p_id=6259&seq=1&format=3
Inputs/Outputs: (4) HDMI® inputs - (1) HDMI® output
the box is a hdmi switch and only has 4 hdmi inputs and 1 hdmi output.
not sure what you mean about one rca style output. if it is just 1 (one) single plug not colored white or black then it is most likely a spdif coax connection which has rca type ends but a coax wire. typically they are colored orange but i've seen them yellow and black as well. coax is digital, rca is analog. you would be talking about a fancy $50 conversion box which will not give you surround sound (since rca only can carry stereo). a y cable will do nothing if the port is in fact coax.
not sure why it would be a single rca red+white (ie just one of those plugs) since i've never seen/heard of such a thing being on a product. lets just say that for an instant that it was this way... putting a splitter on the line would only give you a LEFT+LEFT or RIGHT+RIGHT signal. essentially MONO sound.
in any case the box doesnt support those outputs you may want to see below.
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something like this...
http://www.monoprice.com/Product/?c_id=101&cp_id=10110&cs_id=1011002&p_id=5557&seq=1&format=3#specification
Audio/Video Inputs 3x HDMI® on rear panel, 1x HDMI® on front panel
Audio/Video Outputs 1x HDMI® on rear panel
Digital Audio Outputs 1x S/PDIF Optical (Toslink)* and 1x Digital Coax*
Analog Audio Outputs 1x 3.5mm (1/8") stereo
may work if your home theater system can accept a coax or optical signal because honestly that is the only way that you will get surround sound. rca (red+white) is just not capable of providing surround sound at all (it is for stereo only)
with that said... you would still need to buy a digital conversion box for antenna (the external tuner type box) since i'm not sure if you can manage to find one of these such boxes merged with a hdmi switch. essentially that would be a perfect product for you however i dont think one exists and if it does i'm not going to spend hours looking for one
(though you can have a look if you like)
essentially...
-blueray plugs into switch box via hdmi
-console plug into switch box via hdmi
-antenna goes to conversion box then conversion box plugs into switch box via hdmi
-switch box outputs hdmi to tv
-switch box outputs coax/optical to sound system
HOWEVER, this particular product will only work if you have spdif optical or coax input on your home theater. i do not believe you told me if you did or not. if you do not how the hell are you getting surround sound out of it now?
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now i did just pick a product out of a hat which had the connections needed. you might want to give it a bit more thought or search around for other products similar.
you also want to tell me for 100% sure or find a photo online of the rear panel of your equipment or take a photo yourself (ideal). i need to know what all of the audio inputs are on your home theater. the most important thing to know is if it has spdif optical or coax support. if not you need to list everything.