New Motor, Impeller and Diffuser- loud Noise

I replaced my motor and impeller last year and noticed a louder than normal ‘whine’ and figured I’d deal with it next year. Well next year is here and the noise is still there. I recently replaced the diffuser and no change. Flow is great and there are no bubbles, cavitation, leaks etc. just a slightly annoying sound. I don’t think I have a bearing issue since the motor is brand new. Any thoughts?

new motor is a Century 1 HP USQ1102.