It is generally around 7-8k. I’ve found that speaker height and toe in can make a difference. My speakers have level control of mids and highs, and using a calibrated mic and RTA to voice them differently helps a lot. I can reduce that 7-8k range and almost eliminate the sibilance.
A high quality studio de-esser is something I’ve considered as a last resort. I wish more mixers used them effectively. Compression accentuates natural sibilance and some singers have sibilant voices. It can also be accentuated by mastering compression.
