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.