There appears to be some movement in the contentious negotiations between Broadway producers and the musicians who staff the pits of the Great White Way. The central issue in the talks is over the requirement that a minimum number of musicians be employed for every show. Producers have been insisting that the policy must be eliminated outright, but sources now say that they may be willing to accept reductions in the minimums instead. Why the change of heart? It’s possible that producers aren’t as ready as they suggest to start using canned music as accompaniment to Broadway musicals.