Haible Juergen wrote: > Two comparators to detect the zero crossing of L and R signals. > The comparator outputs go into an XNOR gate. > The output of the XNOR goes into a simple RC LP filter, and then > into a bargraph chip. This is exactly how the "Korrelationsgardmesser" in "elrad Studio 1 Remix" works... it's a DIY project with PCB layout. Ingo