Whistling Tub Faucet

I just re-tiled my tub surround. I took off all the fixtures, but left the plumbing alone. It is 12 year old builder installed copper pipes. Fixtures are Moen, probably the cheapest model, single handle control with a pull-up thing on the faucet to turn on the shower. I put on a brand new Waterpik hand-held shower head.ow. Now, when I turn on the shower there is a loud, high pitched whistle that comes out of the faucet. It goes away after the water runs - it takes 20 seconds to a minute for the whistle to stop. I've tried draining the system again but that didn't work. Does anyone have any ideas?

Thanks!

Replace the tub spout...the Delta spout with the pull-DOWN divertor is highly praised by the plumbers here. I just installed on at my mother's house, and it does work well.

From the shower head?
Sometimes I drill the restrictor a little larger to change the frequency.
They can be kind of shrill sometimes.
You may also have a vacuum breaker on the hose causing the sound.

You may want to remove the handshower and see if that isolates the noise.
Then you will be closer to the fix.

Still think it is the spout divertor...try playing with it, I'll bet you can change the pitch or effect by moving it slightly (hard, since it is held in place by the water pressure, but you cna do it). That seal gets bad after awhile, and the only thing you can do is replace the spout...most are not repairable.

Thanks for the responses. I tried switching out the shower head and got the same problem with the other one. I tried playing with the divertor but it didn't help. So I'm going to take your advice and change out the spout. I couldn't find the Delta model at Home Depot or Lowes, so I bought the brand they stock, Danco. Any reason not to try that brand?

Thanks again.