honestly i feel like the tone was decent, but they probly just drop tuned the bass without getting it set up. so those strings are just super loose, floppy and gnarly sounding. u might try and using a multi comp to see if u can tighten it up... but like i said its not so much the tone its just the sound that was recorded from those strings. try taming some of the muddy low mids on it and if that dont work then they might need to retrack the bass. and if they bitch, tell em "if ur gonna drop ur guitars, do it right, or get dead floppy bass tones"
thats why i tell all my potential clients to get their guit-fiddles set up and put new strings on before they even think of commin in, same with drums and new heads.