If the Amazon Echo is not powerful enough, you should consider the higher-end Echo Studio. It was unveiled in September and is Amazon's answer to the Google Home Max. It's currently down to just $170 and comes with a free Hue bulb, which represents a $60 discount over the traditional MSRP.
For this price, you get high-quality audio, coming from to the 1" tweeter, three 2" mid-range speakers, and 5.25" woofer, which can deliver up to 330W of peak power. Thanks to the Dolby Atmos and Sony 360 Reality Audio technologies, the Echo Studio can deliver an immersive 3D audio experience. Also, just like its competitor from Google, the speaker can automatically adjust itself to the acoustics of a room, without even having to ask for it. It naturally comes with Alexa, and also has an embedded Zigbee hub. The latter will be particularly useful to control the free Hue bulb, which costs $25 when sold separately.