Echo (4th Gen): Your Smart Home Hub with Premium Sound and Alexa! - YouTube
Amazon Echo Plus 2nd Gen Premium Sound With Built-in Smart Home Hub Charcoal 841667133638 | eBay
Echo (4th generation) | Premium sound Wi-Fi and Bluetooth smart speaker with Dolby, smart home hub and Alexa | Twilight Blue : Amazon.co.uk: Amazon Devices & Accessories
Amazon Echo and Dot Alexa speaker upgrades tout better sound.
Echo Dot 4th and Echo Premium Sound - What to expect from them? - YouTube