I posted this originally at the Pro Audio Design Forum of a click I captured in the wild.
The RIAA de-emphasis was done in Cool Edit and is FIR so it may not be representative of phase-accurate RIAA implementations using analog EQ or IIR RIAA.
This particular example is a rather large click having a typical strong Side L-R vertical component.
I didn't have to look hard for this needle in the haystack: It was the first big click in the file.
Anatomy of A Phono Click, No RIAA, Flat Transfer. Note strong L-R (Side, Vertical) Component.
This is the same click after RIAA EQ:
Anatomy of A Phono Click, With RIAA Equalization (FFT).
Note the time-smearing and increased difficulty of detecting the click if RIAA EQ had been used during recording.
And it's primarily a Side, L-R, vertical event.
This click would have been almost at right angles to the mono line when viewed in Vectorscope X-Y mode.
I don't know if all click auto-detection methods are friendly to flat files but the Virtos DirectX plugin used with CE seems to be.
I haven't done a lot of work yet with DC8 to know.