If the sound is fine when playing music using Bluetooth, we recommend you try the following:

Delete the Google Home app from your phone or tablet.

Reset your CITATION ONE/100/300/500

Press and hold the reset button on the bottom of your CITATION speaker for about 15 seconds or tap the display of your Citation speaker, go to Options and choose Factory Reset. Your speaker will restart and will then be ready to be reconfigured.

* For the Citation 200: Press and hold the Volume Down and Voice Assistant button simultaneously for more than 10 seconds.

If you have a standard provider router with a 2.4 GHz and 5 GHz home WiFi network, we recommend that you separate these two bands by giving the 2.4 GHz and 5 GHz networks each a separate SSID (network name) and password. 

To do this, you must log into the modem. If you are not sure how to do this, we recommend you contact your Internet provider, who will be able to assist you with this over the phone. 

In the network section there's an article witch explains how this can be done manually. Afterwards, be sure to connect the phone or tablet to the faster 5 GHz home WiFi network before you run the setup again. If you have made changes to your network settings, make sure that all your devices are registered on the ‘new’ network and make sure to forget any other networks with which your phone/tablet was configured to connect automatically. 

Also please check out the article about preventing interference.