" If they impart no sound character, why have some people commented about an improvement in exchanging components of the same values? "
There are places in a crossover circuit where the characteristics of the components matter more than others. The Zobel is among the less critical locations in the circuit; in contrast, the series capacitors are quite critical.
Just my opinion, but "my speakers... can occasionally sound edgy, particularly noticeable with voices at higher volumes" sounds to me like a much bigger issue than can be addressed by exchanging Zobel parts, especially if their quality is high to begin with.
Duke
There are places in a crossover circuit where the characteristics of the components matter more than others. The Zobel is among the less critical locations in the circuit; in contrast, the series capacitors are quite critical.
Just my opinion, but "my speakers... can occasionally sound edgy, particularly noticeable with voices at higher volumes" sounds to me like a much bigger issue than can be addressed by exchanging Zobel parts, especially if their quality is high to begin with.
Duke