Hello,
I also experience this with my TSR3 3 wood and I was told at the local shop when I brought it in is it's the wind going through the underside weights and it doesn't affect the ball flight or performance in any way. I'd love to hear another opinion though because I heard mixed messages previous to bringing it in physically to my local shop.

My TSR3 4 wood 16.5 makes a loud whistling sound too. My golf shop sent it back and titleist sent a brand new one… that still whistles loudly

I have the same club but never heard a thing from it. One of my favourite woods ever in the Titleist range.

I have never experienced this...it sounds like something is sticking out somewhere or catching the air like a flute or something creating the whistle. I would ask your golf head pro what they think...after closer examination it should be apparent.

Good Luck!

I noticed the same while trying out the Tsr3 3 wood.... Ended up going with the Tsr2 3 wood but not really tried it out enough to notice if it did the same

I'll take that whistling sound any day over the loud rock music some people need to have on when they're golfing.