A carefully made mono mix (L and R exactly equal) will
cancel that part of the the vertical component which is the
same in both channels.
[log in to unmask]
> Date: Tue, 9 Oct 2012 17:36:47 +0000
> From: James Roth <[log in to unmask]>
> Subject: Re: What's the best way to remove surface noise on Columbia Shellac (1930)?
> PLEASE TELL ME
> How does one cancel the vertical portion of the signal?
> Ben Roth