Stunning 360-degree sound with Alexa. The Harman Kardon Astra is a premium voice-activated smart speaker that delivers room filling, 360-degree stunning sound. Featuring multiple drivers and tweeters for high fidelity audio, letting you hear every detail. Astra is powered by Alexa Voice Service. The built-in 4-microphone array with noise cancellation provides best-in-class voice recognition. Just ask and Alexa can play music, answer questions, place an order, control your smart home devices, and more.