Didn’t hear the heartbeat ?


So I had my first ultrasound two weeks ago with a clinic when they thought I was eight weeks. Turned out I was only six. They didn’t do vaginal and I seen the baby and the heartbeat. Then last week at eight weeks I went to my normal physician and they did a regular ultrasound seen the baby and heartbeat but I didn’t get to hear it. I’m a first time mom so do you only hear with a vaginal ultrasound?