Dear Ph.D., Common electrode is already on the cap. And two earclips has to be connected to A1 and A2. Best regards, Alexander > After applying a 19-channel Electrocap to a client and starting to record, > all of the channels appeared identical, and were unresponsive to the usual > sources of artifact. However, the impedances were different. > A friend suggested this could be a problem with the ground electrode. > Plugging one of the earclip electrodes directly into one of the two ground > sockets on the Mitsar didn't help-- presumably because the ground from the > cap continued to have the same problem. However, I don't understand the > nature of this problem. > Any ideas about whether this a cap problem? a ground electrode problem? > or, a software (e.g., end-user-ignorance) problem? > Thanks! > Jon Frederick > QuietMind Foundation > Lafayette Hill, PA Best regards, Alexander