Thanks, but unfortunately that’s not the correct answer. After some deductive investigation last night, here’s where we are: Audio channels 1-4 and 5-8 are duplicates, so we could eliminate 5-8 using the method you describe above. However, the waveforms are all different on tracks 1-4, and eliminating 3 & 4 results in a loss of information. (For instance, the -12 db tone at the beginning of the tape is at -18 db without tracks 3 & 4.) This may be adjustable by a setting on the Panasonic AJ-HD1400 deck, but we have not been able to decipher the incredibly arcane manual or find any technical support over the weekend. Any other suggestions would be greatly appreciated.