Fuminori Ōhashi Blu-rays

Restored original mono mix: Toho Japan 4K Blu-ray
Unrestored original mono: 2014 BFI Blu-ray

BFI 4K Blu-ray has OG Perspecta (in 5.1 container) and a stereo downmix of it; no original mono.

Additional Info:

The unrestored track on BFI's earlier release appears to be an almost entirely unmanipulated transfer of the original mix. It suffers from a distracting low-frequency hum. The 4K restoration comes with a restored track, which appears to be the same transfer, but which appears to be cleaned up with a moderate amount of noise reduction and some EQ, nicely opening up the high-end, and which is likely to be preferable to most listeners. All earlier releases sound poor.

Perspecta isn't a discrete surround format, instead only relying on manipulating volume and panning of the mono track across L/C/R channels, based on embedded control tones. As such, even the Perspecta track is technically just the mono mix, though the omission of the proper mono on BFI's 4K is still unfortunate.

The Hidden Fortress (1958)

4.2

Director: Akira Kurosawa

UHD Blu-ray

Best English-Friendly:

BFI 4K Blu-ray

Best Video:

BFI 4K Blu-ray has excellent master and grade, no DNR and tasteful HDR

Best Audio:

Restored original mono mix: Toho Japan 4K Blu-ray
Unrestored original mono: 2014 BFI Blu-ray

BFI 4K Blu-ray has OG Perspecta (in 5.1 container) and a stereo downmix of it; no original mono.

Additional Info:

The unrestored track on BFI's earlier release appears to be an almost entirely unmanipulated transfer of the original mix. It suffers from a distracting low-frequency hum. The 4K restoration comes with a restored track, which appears to be the same transfer, but which appears to be cleaned up with a moderate amount of noise reduction and some EQ, nicely opening up the high-end, and which is likely to be preferable to most listeners. All earlier releases sound poor.

Perspecta isn't a discrete surround format, instead only relying on manipulating volume and panning of the mono track across L/C/R channels, based on embedded control tones. As such, even the Perspecta track is technically just the mono mix, though the omission of the proper mono on BFI's 4K is still unfortunate.