Normally we do not ship resistors with speakers as they really aren't needed in most cases. We voice our speakers to be flat and accurate as possible. But some people are overly sensitive to high frequency sounds or are in extremely lively rooms with no acoustic treatment.
In those cases, we can supply resistors that will reduce the output of the tweeter. The resulting speaker will no longer measure flat and accurate but will address this situation. So we only supply them when the situation warrants (which in most cases do not).
- Jim