split system copper piping and silencer boxes

Hey guys, Wondering how people have soundproofed the hole in the wall which is needed to run the pipes from the external compressor unit to the head unit inside the room (for split system units). From what I understand you cant bend those copper pipes around the bends within a silencer box. OR am I wrong? My plumber came over today and he recommended putting a 70mm pvc pipe within the wall cavity during construction to later run the pipes, cables, etc, through. But im not real keen on having a 70mm hole in my walls! Do most people just drill holes big enough to run the pipes then just seal it with caulking? thanks

Do most people just drill holes big enough to run the pipes then just seal it with caulking?

Exactly! And also make sure that the pipes do not run straight across the air gap in the wall: Bend them carefully 90° (wide radius) as soon as they get trough the inner-leaf, so that the run parallel to the surface, then make a large loop inside the wall, then bend them carefully back the other way 90° (also wide radius) and take them through the outer-leaf. Make the hole a bit bigger than necessary to allow plenty of caulk, for a really good seal. - Stuart -