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October 12, 2023

ASUS Uses Dual Force-Canceling Woofers in the iMac's Sound System

As much as we all love Apple for bringing some of our favourite sci-fi tropes to the real world, the use of force-cancelling woofers in the new iMac’s sound systems might have you scratching your head. Sure, we’ve seen these types of woofer arrangements in high-end audio before, but they typically work by firing a pair of drivers at each other to cancel out the reactive forces causing cabinet vibration and distortion.

This is important, because sounds at very low frequencies tend to produce stronger, more noticeable vibrations in speaker enclosures – which can lead to unwanted rattling or even hum. In some cases, these vibrations can be transferred to the main speakers, resulting in muddy or inconsistent bass and choking dynamic range higher up in the frequency spectrum.

To tackle this problem, ASUS has employed dual force-canceling woofers in the GX703H, GU603H and GA503Q series ROG Gaming laptops. They are positioned in pairs and slightly offset to cancel out each other’s vibrations, making it easier for the main speakers to reproduce low frequencies without being compromised by unwelcome resonances.

Essentially, this is based on Sir Isaac Newton’s third law of motion; for every action, there’s an equal and opposite reaction. When a single woofer pushes outward in response to a signal, it generates slight acoustic vibrations in its cabinet which can transfer to the floor and cause it to rock. But when two identical drivers are positioned in opposition to each other, these mechanical motions cancel out – meaning the cabinet won’t rattle and rock.