What 50's or 60s' female group sang a song where one member sang a line in a deep voice.
I was in a Dairy Queen and they were playing a fantastic mix of I'm guessing 50's and 60's music. One song caught my attention that was by a female group. I was in conversation and couldn't focus on the song, but I recall a repetitious line that was said 2-3 times in a normal voice, but the last time was sung much deeper.
da dee da dee da dee da dee da dee da daa (much deeper)