Was is the Ecclesiarchy Approved Diadem on the Zealot, I wonder? For visual reference, it’s a spiked iron halo with something that looks like a vent cover on your face
EDIT: Link for visual reference Ecclesiarchy-approved diadem helmet for zealot rebreather effect but
That’s the only one I know of, but it stands out quite a bit - adds a deeper, kind of robotic sound. Honestly sounds amazing IMO on male Judge Zealot.