Have you seen the 2007 movie version of Sweeney Todd at all (the one with Johnny Depp and Alan Rickman?) I personally really liked Alan Rickman as the Judge, and he wasn't a bad singer either.

i was actually JUST watching it last night this is so funny but yes i have! i think it gets a bad rep sometimes because it's a movie musical in the same vein as phantom of the opera 2004 but visually it's one of my favourite adaptations of sweeney todd because of how well it utilizes it's victorian london setting and makes it feel as gritty and grimy as it would have been. as for judge turpin i think alan rickman and timothy spall are kind of underrated when it comes to their respective portrayals. judge turpin needs to have a particular kind of ick factor and imo both alan rickman and philip quast (from the 2014 lincoln center half concert half staged production of sweeney todd that you can actually find on youtube for free should you wish to) are easily the best because the 2014 lincoln center version has mea culpa in it (a song that seems to get cut more often than not because it's literally just judge turpin self-flagellating and singing about how he's lusting after johanna à la judge claude frollo in the hunchback of notre dame) and both philip quast and alan rickman just. play judge turpin in a way that is both weirdly charismatic and also so fucking sleazy that it just makes sense.