I noticed this noise works pretty well to get a cat’s attention. Any ritual involving treats will send are cats coming in from any corner of the house/backyard with this noise- they have excellent hearing of course.
But why this noise? Why not their own name? Sometimes even this doesn’t work, the cat simply does not want to come over, and just stares at me. He knows I’m trying to call him, and he’s just torturing me inside 
Maybe it’s because cats hiss when they’re upset, frightened, or angry.
We always made kissing noises when calling our cats, along with the “HEEEEEREEE KITTYKITTYKITTYKITTYKITTYKITTYKITTY!!!”
My cat also responds to this sound… always has… but it’s probably because she’s been conditioned to either get a treat or get rubbed if she comes around. She sometimes ignores it as you say your cat does, but that’s because she sometimes doesn’t want anything from me I suppose.
Sounds like the same pshing sound I use to attract wild birds. I’ll guess it sounds like a bird. What self respecting cat can ignore a bird?
I suspect it’s because it resembles a rustling sound. Cats are attracted to rustling sounds (the way I call one of our cats is to scratch at the fabric of the chair I’m sitting on, or the rug). Cats respond to rustling sounds because it’s how they catch their prey (mice rustling in leaves, etc.) – I think it’s hard-wired in. You catch a cat’s attention with the pss-pss-pss, especially when you’re first training it, and it learns that if it responds when you call it, it gets a treat, or a rub.
Not all cats respond to “pss-pss-pss” (Although it does get their attention). Our neighbor’s cat, for instance, comes when I whistle, as for a dog. Another at I used to know ran away when you made the “pss-pss-pss” sound. Until you called him by name. Then he’d run to you, apparently because knowing his name proved that you were a “good” person, more likely to pet him than beat him.