Fred75, Thats a pretty broad statment. Like you make a claim so do I. With my speakers it made no difference. SIngle wired worked as well if not better. Very few speakers wil benifit from bi-Wire. Bi-amping does work.
Like I said, speaking to many speaker makers, bi-wire was added by 95% of them as a marketting ploy to keep up with the Joneses. What they say is Double post for Bi amping single posts for single amp use.
The wire makers in conjunction with thier bought and paid for reviews made a big deal about this. WHY? To sell double the wire. Period.