Tying multiple audio sources to one set of speakers?

Hi folks,

I'd like to describe what I'm trying to do and hopefully get some guidance one the best way to go about it. In a nutshell, what I want to run multiple different audio sources through one set of speakers, then put some kind of cap on it so nothing gets too loud.

I have a large number of PCs I use, plus other sources(game consoles, video editing equipment, cable box, stereo, etc), hooked up to an array of video switchers and splitters. Total count is 8 monitors and change, and most switch between more than one source. I don't want to have to have independent speakers for every device(or have to go fumbling for a bunch of different remotes) nor can I use the built in TV/monitor speakers as I may be trying to get audio from one source and video from another.

I also desperately need some kind of solution to cap maximum volume/DB coming out of the system Part of it is the age old "Explosions are too loud and dialogue is too quiet" issue, but with so many different audio sources you can bet that every five minutes one of them is too darn loud. I have particular issues with a game I play that uses a voice-chat; the game cannot remotely level out everyone's voices, so it ranges from too quiet to hear and "neighbors going to call the cops" loud. In order to bring up the low-end I really need something that can just cap the maximum decibel volume so no matter what nothing will ever be louder than a set volume.

My first attempt at solving this was to buy a mixer board. It worked well for giving every device individual volume control but doesn't help with the min/max issue. I have to "ride the control" any time I'm watching an action movie, and it's an even bigger issue with games and things. I've tried an equalizer but there it was going to take too much fine-tuning. I've heard that there exist things that can limit the maximum decibel but haven't been able to find one that worked(tried one desiged for keroke machines but all it did was make a buzzing sound when plugged in). What I'd really like is something with some kind of simple control that I can run a tone through and set a certain amount as the loudest noise I ever want to hear

I've also tried enabling "smart sound" and what have you, on the TV using the TV's speakers it didn't help enough(certain things were still way louder than I ever want), and that only works on the TV's speakers; not what I'm after. If there is some kind of standalone device that does smart sound better I'd be very interested.

To further complicate matters, me and one or two of the audio sources are in one room, and the rest are in another using cables running through the wall. I've had no shortage of issues with interference and I don't know why; has made me give up entirely on providing sound for a couple pieces of equipment.

I'm not exactly an 'audiophile' per-se, so quality isn't a huge issue as long as there's no buzz/interference(to which I am extremely sensitive). Unfortunately this makes knowing what to buy a real challenge, since "inexpensive" seems to be code for "buzzes a lot and doesn't really work".

Anyway, I know this is a complicated setup, hopefully someone here likes a challenge!

Any help is appreciated.

Thanks.