1)   dolby surround meter 2006
The levels of all six channels as well as the phase correlation between all combinations of two channels are represented, so that defined statements are possible for the mono compatibility of a stereo and a Surround signal
IEC 268-10 Type I - Nordic N9, BBC PPM, IEC268-10 Type IIb - EBU PPM, DIN 45406, Surround, K-System, K-20, K-14, K12,