Maxell XLII 90 (1994) (my calibration reference)
Relative sensitivity: (reference)
THD @ Dolby level: 0.62%
MOL400(THD=1%) : +1.8dB
MOL400(THD=3%): +5.3dB
MOL1k(THD=3%): +5.5dB
SOL10k: -3.4dB
Bias noise: -54.8dB, -59.2dB(A)
Dynamic range: 64.5dB
I repeat here the results for the tape my Nak BX-300 is calibrated for in type II position, the 1994 XLII. All following results take this as reference.
Agfa CrII-S Superchrom HDX (1982)
Relative sensitivity: -2.2dB
THD @ Dolby level: 3.3%
MOL400(1%) : -7.5dB
MOL400(3%): -0.4dB
MOL1k(3%): -2.8dB
SOL10k: -7.4dB
Bias noise: -55.8dB, -60.6dB(A)
Dynamic range: 60.2dB
This is, uniquely, a ferro-chrome for the type II position. Here too the chrome layer has aged, losing its sensitivity (you can learn more on CrO2-aging here). Reducing bias flattens the curves, but the ferric layer cannot save the day and consequently MOL is very low. So is noise ... Like about all Agfas I tried from that era the shell is very chattery during winding.
Agfa Stereochrom HD (1984)
Relative sensitivity: -3.2dB
THD @ Dolby level: 4.6%
MOL400(1%) : -8.6dB
MOL400(3%): -2.0dB
MOL1k(3%): -2.7dB
SOL10k: -8.1dB
Bias noise: -55.1dB, -59.6dB(A)
Dynamic range: 57.6dB
Agfa C-DXII (1986)
Relative sensitivity: -3.5dB
THD @ Dolby level: 5.6%
MOL400(1%) : -9.4dB
MOL400(3%): -2.9dB
MOL1k(3%): -3.6dB
SOL10k: -7.7dB
Bias noise: -55.4dB, -60.1dB(A)
Dynamic range: 57.2dB
Agfa C-DXIIS (1986)
Relative sensitivity: -2.7dB
THD @ Dolby level: 3.7%
MOL400(1%) : -7.1dB
MOL400(3%): -0.8dB
MOL1k(3%): -3.0dB
SOL10k: -7.3dB
Bias noise: -54.8dB, -59.7dB(A)
Dynamic range: 58.9dB
Agfa SR (1989)
Relative sensitivity: -0.4dB
THD @ Dolby level: 1.4%
MOL400(1%) : -1.3dB
MOL400(3%): +3.2dB
MOL1k(3%): +2.9dB
SOL10k: -5.2dB
Bias noise: -53.8dB, -57.7dB(A)
Dynamic range: 60.9dB
And again something weird and wonderful from Agfa. This tape is greyish-black, yet it lacks the smell typical of chromium dioxide product. MOL, sensitivity, and noise are too high for degraded chrome, yet too low for a good ferro-cobalt tape. It is likely a magnetite-based ferro-cobalt, possibly the first type II with that chemistry. And that might make it the precursor of the 1991 Maxell XLII-S, if you know that there was cooperation between both manufacturers at that time!
Allegedly part of SR production was loaded with CrO2.
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