It's pretty boring. They'd originally planned it as a sequel to the previous year's Phantom of the Opera and that's not my favourite either. The sets are impressive (although familiar) and I like Boris Karloff, but that's it.
Firstly, the opera. This film contains too much singing. Karloff is playing an opera house doctor, who ten years ago had an obsession with one particular singer (June Vincent). She hasn't been seen since then. Today the opera house's impresario is getting on with the business of putting on shows, slapping down prima donnas and telling random understudies or music students that they're playing the lead role instead. Almost the whole cast is part of the opera company, or else is closely connected to it.
What's distinctive about all this is that the film's trying to be a bit classier than the B-movie you'd expect of Universal horror films. It's in colour! (Karloff had never been in colour before.) It has the same leading lady (Susanna Foster) and was shot on the same lavish sets as the 1943 Phantom of the Opera, which itself had used the famous opera house set that was built for its 1925 predecessor. This was a movie designed to play in cinemas that wouldn't have dreamed of showing Karloff's other release that year, House of Frankenstein. Accordingly the trailers and publicity material played down the horror angle and avoided mentioning that people like Karloff and Turhan Bey had also been in Universal's less prestigious monster movies.
Visually, it's more than up to the job. It's got all those big expensive-looking sets to at least give the appearance of quality, but at the same time the director overcomes the handicap of colour by making such strong use of shadow and darkness that he almost had me wondering if this wasn't a colourised version of a black-and-white film. These are really interesting visuals. It's like black-and-white with added colour, if that makes sense. Its compositions make dynamic use of darkness, making lots of interesting shapes on screen and creating more dramatic effects than you'd expect in a colour movie. Obviously you'd still sooner watch black-and-white any day, but nevertheless this is well worth a look. I see the film was Oscar-nominated for Best Art Direction, albeit for interior decoration (i.e. the sets?) rather than cinematography.
The downside though is that they over-indulge the singing. There's one long stage number that they simply run from start to finish, albeit with a few reaction shots from the audience to keep in vague touch with the idea of drama.
The story is pretty routine. Karloff's basically another Phantom of the Opera, but without the scarred face and still living a respectable life in society. It's solid enough and there's nothing wrong with it, but it's not going to blow you out of the water.
The cast are where the film loses it, though. The acting here is surprisingly bad. Karloff's a speed bump even if you eventually decide you like him, but Turhan Bey would have stank in an amateur production. His role isn't even difficult! He's got to love Susanna Foster and be happy for her, but he can't even do that. Foster isn't great either, being bland and an unconvincing singer, but put the two of them together and you've got a movie whose romantic leads don't work at all. (They're charming in their first scene as enthusiastic music students, though.) This wouldn't be so bad if this were a Hammer horror in which the young pretty lumps of wood aren't particularly important and it's all the Cushing-Lee show, but unfortunately the plot's built around Foster. She's as central as she was in Phantom of the Opera and it kills the movie. The director's doing his best and I'm sure most people won't have reacted as strongly as me, but for me his film's just dead weight.
As for Karloff, everyone seems to think he's sleepwalking through this one. I disagree. I completely see why people say so, since he's delivering melodramatic dialogue so mildly that it sometimes makes him look ridiculous, but it struck me as an acting choice. He's playing the role as mad, and not in the usual hammy way. Karloff here has the impeccable, sad courtesy of someone who's had such a shock that they're empty inside. His more blood-curdling lines lack weight because the character's trapped inside his own head. This is clearly a counter-intuitive acting choice, but I found it both valid and subtle. Some of his line deliveries were a bit limp even for me, but I found him very watchable, actually.
The other actors have their ups and downs too. There are a few line deliveries to make your nose wrinkle, but I liked (without loving) Gale Sondergaard and whichever lady was playing Karloff's housekeeper. Sondergaard in particular manages to be obnoxious enough to sell the impresario's extreme casting decisions, but without ever letting the character be a monster.
Did I like this film? No. My attention wandered and I was clock-watching, despite the fact that it's relatively short (although long for its time). Karloff's fans apparently hate this film and I can easily believe that. I wasn't invested in what I was watching. The singing is obviously dubbed, while I neither believed in nor cared about Turhan and Foster. Personally I'd recommend watching this film if you've just watched and enjoyed the 1943 Phantom of the Opera, because it's very much a companion piece and I didn't like that film, so you might disagree with me on this one too. Foster isn't even the only crossover actress between the two, since one Jane Farrar is also in both.
If you do watch it, keep your eyes on Karloff. The backstage opera stuff's okay too, I suppose.