Speaker interferance when external HDD is switched on

Hi, new to this forum.

So I recently purchased an internal HDD, placed it inside a HDD enclosure. As soon as I switch it on, it causes a continuous buzzing/interference in the speakers- it seems to be worse when the volume is turned down. The casing is a metal material. I have another seagate external HDD, which is not causing any issues with sound.

Any help with be appreciated as the buzzing noise is giving me a headache

If the new one has its own power supply it could be bad. It could be cheap/poor design of the interface in the case. Try it in another usb slot or on another computer to be sure it isn't the slot. You might be sure the drive is making good contact with the case.