Just found a web site where you can download free mp3 sounds for calling fox's. I have just burnt them to a CD and pluged cheap €2 shop speakers into the walkman CD player to try them. I don't know if they are any good but its driving my dog around the bend listening to them playback.
The sounds are free to download no copyright. Go to bottom of the page @......
I'm just getting back into shooting so I can't try them out myself just yet.