Martin Fisher from the Center for Popular Music at Middle Tennessee State University wrote me this morning and he identified a subtly different failure mode that I had not specifically thought of previously. I think the following best describes it and its remediation.
Manufactured with insufficient lubricant: This is a defect that appeared at birth, so while not a degradation (i.e. getting worse over time), it will still cause issues with reproduction. What distinguishes this failure mode from “Squealing, limited shedding” is that there is frequency modulation introduced during the original recording which was presumptively made when the tape was new. While adding additional lubrication will reduce the frequency modulation during playback (which is very important), it will do nothing to correct the recorded-in frequency modulation. The only method of correcting that is bias capture with the same head as the audio capture and running the resultant files through the Plangent Processes.
To look at it slightly differently, we can correct for stick-slip induced modulation during reproduction by reducing or eliminating the stick slip by additional lubrication, but there is no physical process that can be applied during reproduction that will reduce the stick-slip induced modulation that occurred during the original recording process. If the recording currently on the tape was made long after manufacture, it might be indicative of the tape falling into the normal “Squealing, limited shedding” failure mode, as that version of soft binder syndrome might have progressed from the time the tape was manufactured to the time it was recorded. While philosophically interesting, it does not affect the recovery methodology. However, the analysis of the increased frequency modulation of the recording could point to tape or transport issues. The profile of the frequency modulation can help understand this. It is more likely the fault of the tape if it is totally random, while the transport typically will introduce cyclical frequency modulation related to the speed of rotation of components in the tape path.
For further information please see my ARSC paper and the page with additional tape-specific suggestions.