iTunes Match wont match a song in the store that i already own, recorded from vinyl I have a rather large vinyl collection, some of which i have recorded to mp3 and added to my iTunes collection over the years.

I have noticed that some of them are not being matched, and i am wondering what the cause is.  I have updated the track and album info, but it still doesnt match. 

For example...

In my collection (notice it says uploaded, not matched) -
 

and in the store -


It located and downloaded the artwork, yet it still wont match.

I understand from reading this question that it uses gracenote for matching, which may read parts of the waveform.  Surely the waveform of my vinyl recording is the same, regardless of gain level?  

One thing i have noticed is that my recording is 16 seconds longer - maybe this could be the issue?
Surely the waveform of my vinyl recording is the same, regardless of gain level?


Unfortunately it does not appear to be that simple. Many factors can affect the quality of a digitised vinyl recording such that it will not match the digital fingerprint Gracenote is comparing against.

There is an interesting discussion on Apple Support Communities with suggestions on how to improve the digitised vinyl version so that it better matches such comparison services where possible:

https://discussions.apple.com/thread/3507807