The Blue Angel (1930)

(The German version)

The Kino, Masters of Cinema, and Universum blu-rays use the same audio track completed by TransitFilm, with a few minor differences:

• The opening 10 seconds of the opening aria melody from Mozart's Magic Flute are missing on the Kino and Universum
• The MoC has this music intact, as it splices in the entire opening sequence (~2 minutes, 45 seconds) from another source
• The Universum blu-ray is incorrectly pitched 0.7 semitones too high

These differences ultimately amount to very little because all three sound very, very poor. TransitFilm has chopped off all information above ~7.5 kHz and boosted the lower-mids, leaving the entire film sounding distorted and (ironically) with a much higher noise floor than it did pre-restoration.

The 2001 Kino DVD and the 2003 Eureka DVDs sound basically the same (the Kino underwent a PAL to NTSC conversion), and they sound so much clearer than the blu-rays. 

What the experts had to say:

There are two standard audio tracks on this release: German LPCM 2.0 and English LPCM 2.0. For the record. Eureka Entertainment have provided optional English subtitles for the German-language version of The Blue Angel. There are no optional English subtitles for the English-language version of the film. While clarity is quite good on the two lossless tracks, both are plagued with light to moderate background hiss. On the German-language version, however, its presence is at times more prominent. This said, the background hiss never becomes overly distracting, and the dialog remains easy to follow. Additionally, there are no serious audio dropouts or distortions to report in this review. —Svet Atanasov, blu-ray.com

The original German audio is provided via an uncompressed PCM 2.0 mix with English subtitles. For a track this old, practically the only important thing is that the dialogue comes through clearly and without distortion, which for the most part it does. 'The Blue Angel' was one of the first talkies to come out of Germany, so the mix is understandably crude. A great example is when Rath is in Lola's dressing room. Opening the door, all the sounds of the cabaret outside can be heard loud and clear. When she shuts the door, the sound from the cabaret cuts off completely, as if everyone outside had gone utterly silent. Outside of the dynamics of the mix, there are issues stemming from the track's age. There is a persistent background hiss that you can tune out but never dissipates. Sounds at times appear muffled, but not to the point of distraction. Again, given the context, this track sounds as good as one would reasonably expect. —Daniel Hirshleifer, High-Def Digest

Kino Classics Blu-ray presents the 107-minute film in HD with a 1.19:1 ratio and a German LPCM 2.0 soundtrack with optional English subtitles. Kino states that the movie has been restored from archival 35mm elements, and the noticeably upgraded picture is mostly crisp and clean. Some imperfections, stains and scratches do show up from time to time. However, given the age of the film, this is undoubtedly the best it has looked in quite some time. The sound is also clear with only some hiss present occasionally due to age. —Joe Marchese, The Digital Bits

I disagree with each of these reviewers, because I personally can't hear any "hiss," which I define as a high-frequency sound. I hear instead the absence of such high frequencies, as well as a horribly misguided attempt to re-EQ the entire film to sound less 'thin'. What's left is frequently overpowered by a low-frequency rustling that is so much more annoying than any hiss that would have been left in instead.

The blu-rays and the Eureka DVD, level-matched as best as possible:

The Eureka DVD and MoC BD, in sync with each other:

Edit: I goofed. 'Masters of Cinema' didn't partner with Eureka until 2004. The 2003 DVD should be called the 'Eureka DVD'. All mentions have been corrected.

Edit (24/01/2019): The French Films Sans Frontières DVD, while not completely NR-free, comes from an inferior source (as expected) and sounds bad.