As others have said, most sibilance is in the source recording. Different types and brands of microphone produce recordings that are dramatically different, and some are better than others with regard to sibilance.
Try playing back the record at reduced volume level. Problems caused by your playback system will generally increase with volume. It the problem persists at all playback levels, it is probably in the recording.
Try playing back the record at reduced volume level. Problems caused by your playback system will generally increase with volume. It the problem persists at all playback levels, it is probably in the recording.