Brakes whistling/eeeeeeeeeing despite change of pad

At the end of a long ride the other day my rear brake started whistling. I figured changing pads would sort it but it’s still doing it.

Any tips?

It’s definitely the brake as even a bit of braking pressure stops it

Have you checked the alignment of the caliper? Loosen it slightly, hold the lever, retighten the bolts to centre it on the disc

Whistling brakes sounds ace, have you managed a tune?. I’ve got a mono water-ski which when the water is dead flat, sounds like a pan pipe.

We could form a band