Fascinating idea, I really wonder what would happen too! Would it simply boost a person’s local version of the Field Booster just as boosting an item only boosts that item, or could it boost the base field?
I think all audio has intention within it when we speak, to some degree. (This is how we can feel and detect emotions from a person’s tone, how speeches may evoke strong emotions in a listener, and how we can tell whether someone sounds happy or angry or anything in between.)
So, it’s possible that even without embedding the energy into the audio the same way Dream does, it would still have some effect.
One thing that may help if you try making an audio recording, for intent, you can focus on an intent which comes from the third eye chakra. Perhaps you could also speak the activation word with the intent of your spoken recording activating it automatically every hour via recording too, building that concept into your intent in the audio. I wonder what would happen. It’d be very interesting to hear your results!
It probably also depends upon the activation requirements of the field and how “intent” works in activating it. I think it would be possible to activate the Field Booster to some degree via pure intention without speaking the words, similar to Dream’s other sigils, cards, etc. So when you don’t have the sigil and item with you, you might also try experimenting with thinking of the Field booster sigil along with your item with intent when you remember to do so.
I don’t know if doing this would work as well as activating the Field Booster in the usual way, but you don’t have much to lose in experimenting, and you can try to observe whether the results boosted your field afterwards. I would experiment with it myself, but the fields I have are already very strong for me and I imagine they might become overwhelmingly strong if boosted. I’d be fascinated to read your results if you do try any of this!