A new Sonos speaker has appeared in a filing posted on the Federal Communications Commission website online.

The Sonos speaker has been approved by the FCC for Wi-Fi and Bluetooth support, something required before sale in the US, and goes under the current model name and number S18.

According to diagrams in the filing, it is thought to be a satellite speaker and therefore working with a "master device", providing additional spacial support to a home cinema set-up.

The master device is said to be the existing Sonos Playbar, with S18 speakers widening the soundstage left and right.

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An additional benefit will be that it seems the Sonos S18 will be a smarter speaker than the Playbar, with voice assistant support more in line with the Sonos One and Sonos Beam.

Indeed, a diagram of touch controls show similar properties to the Sonos One, so it is expected that far field microphones will be present.

That could come as great news for current Playbar users as that speaker does not have Alexa or Google Assistant support directly. You can link an Amazon Echo device to your Sonos set-up and use it that way - we do with an Echo Dot - but it's not as sleek a solution as having the option integrated into your Sonos system.

There are no further details on the Sonos S18 but, considering that CES 2019 starts in under a week, it is possible we'll find out more soon.