When the need and opportunities arise I’m not adverse to whispered chanting. I’ve noticed however that people on the street often hear me. That has nothing to do with my whispering but a lot to do with the energies invested and therefore the strength of the chant. (I sometimes smile and say, ‘Yoga’.) For contacting spiritual entities there’s nothing simpler or easier, with the exception of death I guess. I use (titled) names and enns. For idiosyncratic reasons I often use my own handmade, 100% natural string of beads when at home. There’s just something about that tactile allure plus the ability to count the chants – although I count them with my fingers if out and about.
Chanting alters the morphic field, calls in spirits whilst building and reinforcing energies which can be directed. I find that low vibration chant works quickest – the stuff you feel in your chest. If you can’t get the subject of your Magick off of your conscious mind, chanting is a great way to exploit that by numbing repetition. And as with all Magickal words, yours travel to the ends of the multiverse. With practice - even when whispering - you’ll know that!
If standing in queues, waiting at the cash register, ambling the streets or just waiting - you can chant. Sans the beads it costs no money. You can’t save time, you can only spend it. Do so wisely.