I'm not confusing them, but perhaps the discussion was unclear... Keep in mind that I'm approaching this from the perspective of a recordist and not a design engineer or academic... in the early part of my working life I made many recordings with a specialty in field/location work and M-S technique... Eric Goldstein -----Original Message----- From: Akhil Lal <alal@xxxxxxxxxxxxx> Sent: Feb 16, 2005 12:24 PM To: rollei_list@xxxxxxxxxxxxx Subject: [rollei_list] Re: Completely OT- Loudspeaker info You are confusing two separate matters. The production of a stereo image has to do with phase and intensity differences between the *two* ears. Group delay, as in the earlier discussion is has to do with the ear's (one only) ability to detect phase changes in a waveform.