Omni IIe Interior Sounder Hum

I recently purchased the Amico 12 Piezo Buzzer on Amazon as my interior sounder for my Omni IIe panel.

I'm getting a pulsating noise from the buzzer as soon as I hook it up. I talked with Leviton and remembered in the quick start guide that a resistor may help the issue. Problem is that it didn't help.

So, has anyone else had this issue? How did you resolve it?

PS - I'm sure this has been asked here before but I did search and found nothing.

Suggestions on good interior sounder less than 400ma?

Thanks.

How do you have "supervise interior sounder" set?
I use Moose (GE) MP-MPI-47. Its Loud and rated at 175ma. Size is 4"x6.5"x1.5" which is great for covering up the old units I take out.