Without a pitch reference you can still locate the in body chakras, at least those in the trunk (1-5). Simply use the phonemes and allow the voice pitch to drop to the location you know the chakra to be in. Then move the pitch very slowly up and down by small increments to actually buzz the area. When you feel the vibration there then continue going up and down around it to finely tune in. Sustain the pitch with multiple breaths until you feel like it is balanced.

Root  phonetic Uh (love)
at perineum facing towards Earth

Sacral Phonetic  Ooo (food)  
3 inches below the navel

Solar Plexus Phonetic  Oh (no)
just below the rib cage

Heart  Ah  (mama)  
at the center of the chest

Throat  Eh(fed)
at the center of the throat