Small removable panels are all you need to have access to shut-off valves and the like. Just build a frame around the portion of ceiling where access is required, the panel is just a piece of gypsum board cut maybe 1/8th of an inch smaller in all dimensions, you finish the edges of the small panel and the opening with J bead secured using contact cement, affix the panel with screws and that's it. If you have to reach what is underneath, run a craft knife in the gap to cut the paint, remove the screws and voilà ! The idea of having to gain access to all pipes and wires underneath is, to my mind, bogus. How many times in the course of owning your home will you have to gain access to properly installed services? The wiring should be good to start with. Same thing, even more so, for the plumbing. It should do its job without problems for a decade at least. If the plumbing starts leaking, you can always cut a portion of wall board out and patch it up after. Patching is easy enough. Cut the opening neat and square near to a resilient channel or nailer, depending on what was used, make a panel of the proper size, screw the panel in, tape using fibreglass tape, apply mud to the gap and blend the patch in by thinning the layer of mud out to nothing, far enough away from the gaps that it all blends in seamlessly. Prime and paint. Paint can be bought at any time in a matching colour, since all paint and home renovation stores have computers for paint matching. The worst case scenario is you paint the whole ceiling over again. Do yourself a favour, bite the bullet at the outset, a suspended ceiling will not do the trick. To my mind, the sound generated in the listening room should stay in that room, the sounds from outside, should not be allowed to enter, as much as that is feasible. The other benefit with a real plaster board ceiling (even better with double layers) is that there is less of a mismatch between the resilience of the concrete floor and that of a massive plaster board ceiling, than between a concrete floor and a flexing suspended ceiling. Short term pain for long term gain. May look daunting, but is within reach of a dedicated do-it-yourselfer. Good day.