Some things are awkward to pack. After I bought a seemingly well packed record deck, which arrived as scrap courtesy of the Post Office, from a totally unsympathetic person in Torquay, I decided to think of better ways of doing things.
The smashed deck was too tight in the box - every impact on the side caused the lid to shatter. But what is rigid enough to fill spaces, and still flexible enough to absorb impacts? Plastic bottles! Lemonade, cola, milk, whatever - rinse them out and pack them around the object to be transported - you can squeeze them to make them fit, then tighten the cap back up and they will assume the the position. I've been using them for some time now, and I can say that they have been a total success as void fillers and shock absorbers - light and inexpensive, and just the job for HiFi equipment.