I believe you may be referring to playing a vertically grooved record 
(hill and dale) switched to mono. This method significantly reduces 
surface noise by eliminating the lateral movement.

joe salerno


On 12/21/2011 6:04 AM, Tom Fine wrote:

> think there is another method where you can put one channel out of phase
> and mix it to a level that cancels noise the most, but I haven't tried
> this and don't remember the details.