How low can you go? Tim Storm who is a singer can take his voice lower than frequencies that can be heard. During one of his performances an ear, nose, and throat doctor in the crowd was blown away by his low voice.
Then it became official, Guinness Records confirmed that Storm has The World’s Deepest Voice, "They use a frequency analyzer, or vibration tester, as some engineers call it. It has a little microphone hooked up to it, and you just sing into it. And it has to be in a controlled studio environment to be free from any outside frequency interruptions. But you just sing into the little microphone, and it picks up every frequency that you’re giving it and tells you exactly how loud you’re singing each frequency.”
Storms low bass voice was first noticed at age eight. More here.