Originally Posted by Neal
I cut the plug off the car GPS (not the same I know but close)
Not the same at all. There is a considerable pulse of energy transmitted down the sounder cable and everwhere there is a joint there is also a reflection. It is easy to envisage a considerable reflection travelling back along the cable until it reaches the connection on the head unit where some of it will be reflected back down the cable until the joint and then some of it will be reflected back etc, etc. In this way a standing wave will be set up on each transmitted pulse and on the returned pulse from the sounder a similar thing will happen. Whether the units at either end will be able to cope with this is anyone's guess.
I suspect you'll find individual screened leads inside the cable and, maybe, an overall screen too. They'll likely be aluminium foil so it will be difficult to make good soldered connections.
As to whether you should cut it. If I had no alternative, I would.