Personally for me it depends entirely of what kind of a working I am attempting. For shamanic techniques, I find a live drum to be helpful. I have had the same drummer every time I do this, so it's difficult to say how it would work with others. Trust is extremely important in situations like this. I can't drum for myself.
Sometimes it seems better that there is no sound at all. But almost always I have my ritualistic iron bowl that I ring nine times prior to working, and also close with this.
I also use rattlers. The drum has a commanding sound, whereas the rattler is more beckoning in a way. One likes to follow its sound and it evokes a sense of curiosity. It's more "soft" than the drum, I think.
I also find that sometimes, especially when working outside, I begin to sing spontaneously. This usually comes as a sort of aftermath of the working- words of praise. Or a calling, and then it would occur at the beginning. I find that I am not naturally very well versed in galdr, so I don't do attempt that very often.
Of recorded music, I sometimes have ambient music on the background but generally for a ritual I like to make all the sounds by myself, or on the rare occasion that I should work in a group, with the others present.
Depends entirely of the kind of working though.