I have been putting together some Black Eagle X Impacts and ran into a very odd situation. While shooting/testing today I noticed a whistle from my arrows. Both 3 and 4 fletch a like. I shot an injexion 4 fletched to check if I had be missing something. All the arrows were fletched the same with wrap, AAE Stealths and glue. The only change I had was putting new points on the BE arrows. They are combo points. They only thing I could think of is the combo of parts creating a whistle through the nock. Have any of you had a similar experience or any ideas. Oh, the injexion flew dead quite.