Apple loves throwing around buzzwords in product reveals and spec sheets, and one that caught a few eyes was the use of ‘force-canceling‘ in the new iMac‘s sound systems. Apple claims these are the best speakers in an iMac yet, but what does a force-canceling woofer actually mean? Is that some kind of Jedi fighting space dog?
It’s nothing quite as sci-fi as Star Wars. Force-canceling woofer arrangements are fairly common in high-end audio, and while they are far from a guarantee of good sound quality, they do theoretically offer some benefits.
The basic idea behind force-canceling woofers is to eliminate unwanted vibrations by having two woofers firing in opposite directions and perfect unison.
Remember Newton’s third law? For every action, there is an equal and opposite reaction. When a woofer moves, the ‘reaction’ has to go somewhere — usually as stray vibrations in the woofer’s enclosure.
These vibrations can lead to the enclosure rattling and radiating unwanted sound. In large drivers, like those in a subwoofer, it can even cause a speaker to move around the floor. By placing another woofer that fires in the opposite direction, the reactive forces are able to largely cancel each other out.
So why would you want force-canceling woofers in your gadegts? Well, if you’ve ever felt like your computer or phone sounds muddy and rattles when playing bass, these extraneous vibrations are often a culprit.
In theory — nobody has actually heard the new iMac yet — the configuration could help prevent these artefacts and minimize distortion.
In hi-fi speakers, you can also deal with vibrations by creating a dense cabinet with dampening materials or carefully chosen geometry, but one can’t expect the same from a multi-function device like the iMac.
None of this guarantees the new iMac will actually sound any good, but hey, now you know. For a more technical explanation — and to see what a force-canceling setup looks like in some hi-fi speakers, you can check out the below explainer by Soundstage Network and audio researcher Jack Oclee-Brown.
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