Spotted by the Walkman Blog, the filing doesn’t name the WF-1000XM4 — Sony’s expected answer to the Apple AirPods 3 and AirPods Pro 2. But as it’s already leaked, and is the only pair of unannounced Sony headphones to do so, it seems like a pretty safe bet that this filing does in fact cover the WF-1000XM4. And that would suggest the true wireless buds are close to completion.
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The charging case design image is simply drawn and only shows a top-down view, but is consistent with the long, slim cases of previous Sony earbuds like the original WF-1000XM3 and the WF-SP800N. Further evidence that this filing covers the WF-1000XM4 comes in a reference to the product as a “wireless noise cancelling stereo headset” — the WF-1000XM3 featured active noise cancellation (ANC) and the WF-1000XM4 is all but guaranteed to keep this major feature.
As for new upgrades, the earbuds in this document use Bluetooth 5.2. That would grant the WF-1000XM4 a number of wireless performance benefits over the WF-1000XM3 as well as the current-gen AirPods Pro, both of which use Bluetooth 5.0. For instance, the WF-1000XM4 could use the Low Energy (LE) Audio feature in Bluetooth 5.2 to play music with lower bandwidth and power drain.
Bluetooth 5.2 also introduces the Isochronous Channels feature, which more easily allows a single pair of headphones to connect to multiple source devices at once, as well as to switch between them seamlessly.
It also looks like the WF-1000XM4 will include an upgraded MediaTek SoC, the MT2822S. This chip hasn’t been publicly detailed yet, but the Walkman Blog claims it’s a rebranded Airoha AB1568. If so, this would give the WF-1000XM4 the same 24-bit/192 kHz lossless audio support as the WF-1000XM3, while significantly improving its power management.
The filing even contains a hint at a potential release window, with the FCC’s short-term confidentiality agreement ending on September 27 of this year. Whatever this new pair of headphones is, Sony will want to formally reveal it before then, so the WF-1000XM4 could well release before Winter 2021.
This would likely bring the Sony buds into competition with the AirPods 3, which is also rumored to launch in the second half of 2021, as well as the upcoming Google Pixel Buds A. With ANC and top-of-the-line Bluetooth connectivity, though, the Sony WF-1000XM4 would be a more premium proposition than either.
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