There’s a very good chance that when most of us try to sing, we find ourselves horribly off key (my singing is closer to William Hung’s than, say, Ray Charles; I still do it). Singing well isn’t easy. It involves tremendous control over our voices, and years of practice — not to mention that environmental and cultural factors, and even our skull’s shapes, either help or hinder us. The voice is humankind’s greatest instrument. British neuroscientist Sophie Scott said in 2012 that “as a sound, speech or the human voice talking is comfortably the most complex sound you encounter on a day-to-day basis.” As complex as it is, it gives us the ability to communicate effectively, complete tasks, and even break world records.

Before we get to those world records, however, here’s a quick rundown of how our voices work. Both our nasal and oral cavities lead to the pharynx, a tube at the back of our throats that splits into the esophagus, which transports food to the stomach, and the trachea, which brings air to the lungs. Our voice box, formally called the larynx, is located at the top of the trachea. And inside of this are two mucous membranes — our vocal cords — stretched across horizontally, with an opening in-between. As we speak, this opening remains relatively closed, allowing the air that passes through to vibrate the cords, thus creating our voice. (You can feel your voice box at the top of your throat, under your chin. Just put two fingers there and swallow; you’ll probably feel it move up.)

The mechanisms behind our voice are already pretty complex, but it gets worse when you start getting into the range of sound people can accomplish. For that, let’s talk about some world records.

World’s Highest Note Whistled

Going back to singing off-key; it almost always happens because we can’t hit the right notes. Push each key on a piano and you’ll hear what these notes sound like. But matching those sounds becomes increasingly difficult as you move your fingers toward either end, and that applies just as much to singing as it does to whistling.

On Nov. 7, 2013, North Carolina School of the Arts student Walker Harnden achieved the world record for highest note whistled — a B7. This note (you can hear it being sung here) falls in the frequency range of 3,951 hertz (Hz). Frequency is sound presented as the number of sound wavelengths, or vibrations, per second. So, a high-frequency note like B7 would look wavier than a lower frequency note. Considering that the normal vocal range for a human averages 125 Hz for men, 210 Hz for women, and over 300 Hz for kids, Harnden goes above and beyond, even tapping into human hearing where it’s most sensitive (2,000 to 4,000 Hz).

World’s Lowest Vocal Note By A Male

Let’s bring frequencies to the opposite side of the spectrum now. Most humans can only hear between 20 and 20,000 Hz, which is why we can’t hear most dog whistles (their ultrasonic range goes from 23 to 54 kHz) or American singer Tim Storms when he hits a G-7 note (0.189 Hz).

Storms, a bass singer for the group “Pierce Arrow,” broke the record for lowest vocal note by a male on March 30, 2012. The note is so low that humans (Storms as well) can’t even hear it — but elephants can. “I can feel them though,” he told CNN. “Yes, I can kind of hear them in my head as far as the sound my vocal cords are making, but as far as frequencies, it’s something more or less that I feel.”

Storms can appreciate his vocal cords’ length for the sound (or lack of) that he’s able to produce. “One of the concerts we had,” he said, “there was an ear, nose, and throat specialist came to the concert. He’s like, ‘Man, I’ve got to look at your vocal cords.’ He said that my vocal cords were about twice as long as normal.”

World’s Loudest Burp

Some of you probably thought that Harnden’s whistle was subpar. After all, that whistle was super low — so how was it high? Too often, the frequency of a sound is mistaken for its loudness, which is measured in decibels (dB). A typical conversation usually occurs at 60 dB, a clap of thunder is about 120 dB, and New York City’s subways regularly produce sounds up to 102 dB — hearing loss begins at 85 dB.

Paul Hunn, however, can burp at an astounding (can we try to beat this please?) 109.9 dB, and holds the world record for it. Thankfully, such loudness only causes hearing damage after prolonged exposure, but if you’re going to watch the Vine video below, you still might want to keep your headphones on low volume.

“[The burping] started in the school playground really, where we used to have burping contests and I used to win hands down,” Hunn said on his website, according to MTV. “I was also known to let one go in the classroom when the teacher’s back was turned. Boys will be boys. I would sometimes practice after school, although this was frowned upon by my parents, particularly my dad… I do believe he’s now secretly proud.”

Hunn still practices regularly to maintain his loudness. He also makes appearances at charity events and in YouTube videos.