{"id":18862,"date":"2021-10-31T00:02:00","date_gmt":"2021-10-31T04:02:00","guid":{"rendered":"https:\/\/splice.com\/blog\/?p=18862"},"modified":"2023-05-09T16:22:59","modified_gmt":"2023-05-09T20:22:59","slug":"what-is-the-phantom-fundamental","status":"publish","type":"post","link":"https:\/\/splice.com\/blog\/what-is-the-phantom-fundamental\/","title":{"rendered":"What is the phantom fundamental?"},"content":{"rendered":"\n

Illustration:<\/strong> Filip Fr\u00f6hlich<\/strong><\/a><\/p>\n\n\n\n

Also known as the ‘missing fundamental’ or ‘virtual pitch,’ the phantom fundamental is a spooky audio illusion that has us hearing pitches that may not actually exist!<\/h2>\n\n\n\n

That\u2019s right\u2014it\u2019s possible for us to perceive a certain musical pitch, even if that fundamental frequency isn\u2019t actually being played through a speaker or instrument. The secret lies in making sure that we’re hearing the harmonics<\/strong> (the higher multiples of that frequency) all at the same time. Today, let\u2019s dive deeper into the phantom fundamental and explore some common examples of the phenomenon that you may have unknowingly experienced yourself.<\/p>\n\n\n\n

Spooky sounds that aren\u2019t there<\/h2>\n\n\n\n

So how is it possible that we can hear something without it actually being there? Sound physics<\/a> and psychoacoustics<\/a> help us understand how complex sounds are constructed, how they travel, and how our bodies interpret them. For example, a musical instrument like a piano can play a note with a fundamental frequency or pitch of 100 Hz, but you actually get much more than that in the form of harmonic frequencies<\/strong> or overtones<\/strong> at regular multiples of that frequency (like 200 Hz, 300 Hz, and so on). Since our ears and brain receive all of these frequencies at the same time and make those harmonic connections, we hear it all as one single pitch instead of a bunch of different parts. Where things start to get spooky is that if we heard those same harmonic frequencies, but without the fundamental base note at 100 Hz, our brains will still<\/em> perceive it as that note!<\/p>\n\n\n\n

It seems hard to believe, right? Below is an example of a single sine wave, with different harmonic frequencies subsequently added or taken away. The first few seconds contain the fundamental frequency at 100 Hz, but it\u2019s missing after that. Despite that, did your perception of the note or pitch actually change? While the timbre<\/strong> or texture of the sound itself shifts around, the pitch we perceive doesn\u2019t change, even when the fundamental (100 Hz) is completely removed.<\/p>\n\n\n\n

It’s all around us<\/h2>\n\n\n\n

Though it may remain unclear exactly how our ears and brain are being fooled here, the phantom fundamental suggests that the upper harmonics are just as important (if not more important) than the fundamental itself when it comes to our perception of pitch. It\u2019s really the relationship between these related harmonics that gives our ears and brain the information they need to reproduce the underlying note. What’s more, it also enhances our experience of quite a few things in the sonic space\u2014below are just a few examples:<\/p>\n\n\n\n