The correct spelling of the phrase "are ones back" is /ɑr wʌnz bæk/. The sound represented by "one" in the phrase is pronounced with a short vowel sound, as in "sun" or "fun". This differs from the long vowel sound in words like "cone" or "bone". The spelling "ones" also helps distinguish it from the similarly sounding word "once". Paying attention to the phonetic details of this phrase ensures proper communication and understanding between speakers and listeners.