Multiple Tv's / Monitors are only a problem if you don't have the right / quality connectors.
I currently have four - five gigs a week, in four different venues, and use a different set-up in each one.
Most recent gig is a large sports bar, with 6 flat screens of various sizes, that was recently re-modeled by new owner ( I had played in the same venue under two previous owners ) and this time they let me have a little input on the Karaoke adaption to their proposed satellite installation. The dss company sent a professional installer down ( 60 mi. ) and I met him and owners at the venue to describe what I thought would make the show, and the nonkaraoke clientele happy during the performance. He had made similar installs all over Tucson, and I learned a few things that day, which led to a happy KJ and the show is building nicely after a couple of months.
1st - All screens have a separate satellite receiver, that is run to the central head unit or junction box.
2nd - The junction box or head unit has a multiple switch that allows rca, or s-video input, as well as a passthrough for the hdmi high definition signal from the satellite, for different viewing for non-karaoke programming. (although I do control the volume to the stage area, and the bartenders are respectfull in keeping the volume low or off, on the sets that are out of my area )
3rd - My connection amounted to an rca cable that runs to my station @ stage left, about 50 ft. from the main head unit to my adaptor which is vga to rca.
I had contemplated running hdmi cable from the head unit to my station, since my computer has an hdmi connection, but if any of you have priced a length of hdmi cable in approximately 50' length, you could hear the moths in my wallet screaming. I was leary of signal loss with rca and multiple monitors, from other gigs, but this guy did what he promised, and I have the clearest signal that I have ever experienced, or have seen at several other KJ's shows that I try to view when time and circumstance allows. So if you get the chance to have a pro setup your gig for video, learn from him, and the permanent setup, makes for easy setup times.
My other gigs run without a stage, due to size limitations; I have one with only one large flatscreen that I get to use the hdmi connection from computer. Another gig I use a wireless transmitter to a second monitor because the property owner will not allow the lessee/business (bar) to run any extra cabling/wiring that cannot be left there permanently, and bar owner doesn't want to lay out the extra cash to allow me to make the connection that I want, then leave it for the landlord, if he vacates the premises. My last gig is with two older tv's that I have to adapt and RF the signal, and one small monitor that I carry with me for private parties and this one gig, and the wiring is substandard ( old coax ) that runs to the bars older tv's, and has been split and poorly wired, and the owner doesn't want me to be crawling around the rafters where there are different stuffed varments that have been collecting dust for the last 50 yrs., so I just make do with what I have been dealt. In most cases, the Karaoke regulars don't overlap, since we are talking about 4 gigs in 3 different cities within about a 20 mile radius, but I do see the difference, and only wish that all the venues could be updated to the connections and ease of setup that first gig offers... did I mention that it is only 3 blocks from my house? lol
So I've got most of the splitters, RF converters, cabling, and adaptor connections that I've used to adapt the tv's and monitors over the years, and quality shouldn't be skimped on, they will serve you well, without the need for replacement, and make your show look professional when installed permanently, as much as the venue will allow!
Check out
monoprice.com for cables and adaptors. I have found them to be very competitively priced.