Subliminal Talk

Question:
what about if I put the speacker on back my head with ultrasonic ?
I have this speacker
http://www.gear4.com/product/_/417/airzone-series-1/

if I put on back my head means swapping the channel , have it same effect ?
or is better put in front or if not possible slightly in best angle possible in front of you?

Swapping channels doesn't matter. Best results come from having one channel in each ear.