Echo Sub review: Echo can finally go deep - CNET

The Echo Sub offers an instant bass upgrade to the Echo line of smart speakers, but stereo pairing two Echos makes for a better music experience.

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Echo Sub - Powerful subwoofer for your Echo - requires compatible Echo device : Devices & Accessories

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Echo Sub review: Add some serious bass to your Echo or Echo Plus speakers

Echo Sub review: Echo can finally go deep - CNET

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