IF cable break in happens, what has been your experience as far as tonal shift?
If cable break-in really happened, and the frequency response really did change over time, then that change could be easily measured and there'd be no more discussion about it.
--Ethan
I believe we have a problem of 2 different perspectives, separated by a common language.
I and many others often 'voice' their systems, not by any topological changes, but simply by substituting nominally equivalent components. I'll swap cables, opamps, capacitors, etc.... until the overally subjective perception is more to my liking. And I might well describe those changes as 'deeper bass', 'more extended highs', 'stronger midrange', etc.... and I'm well aware that upon measurement of frequency spectra, I'll find absolutely no difference between the original and my preferred configuration. The problem is that those changes are
perceived as spectral changes, although to the extent to which I'm able to measure by accessable instrumentation, I can discern no changes whatsoever. But sadly, I am constrained by my perception to describe it as I hear it, while knowing that description is inaccurate, or at least does not correlate with expected measurements. [nor am I willing to engage in that conversation of 'well thats just a tweako bandaid', because when I substitute a specific $6 opamp for a $3 opamp, and my perception of the net result is what was subjectively unlistenable transformed to groovy and mo' betta, thats good enough...]
Heck, I build power conditioners / noise filters for mains power. But seldom do people react with 'I hearing a lower noise floor', rather I typically hear that the bass is more extended and tighter, the treble more (or less) extended, etc....
Sadly, while I know that whatever changes may be wrought by break-in, cable swaps, passive and/or active component changes may not change a spectral analysis, it is unfortunately
perceived as such.
Go figure.

FWIW