In "There Will Come Soft Rains," what are the sources of the voices that can be heard from time to time? What does this suggest about the type of house that it is?

The source of the voices in the house is the house itself. How many voices are speaking in the house is unknown, but I know at least two different voices are present. When the story begins, readers are told about a voice from the living room clock. Then, readers are specifically told a second voice is heard coming from the kitchen.  

"Today is August 4, 2026," said a second voice from the kitchen ceiling, "in the city of Allendale, California."

Late in the story, readers are told about a voice coming from the study. Whether or not that is a third voice is unclear. It could be the kitchen voice in a different room. I do think it is a third voice, though. I imagine each room has an individual voice. That way, occupants of the house can more easily tell which part of the house is speaking to them.  
The voices in the house suggest to readers that the house is a "smart home" from the future. I don't believe that the house is from a future all that far off though. Modern-day smart homes can be voice controlled. Amazon sells their "Echo" for $179. It allows you complete voice control over much of your house. Simply say "Alexa," and then tell it what you want done. If your house has electrical outlets that are WiFi capable, Alexa can turn on and off lights. Alexa can control thermostats too. You can order stuff from Amazon by speaking to the device, and then ask it to tell you the weather followed by a joke. In my own home, I have two robot vacuum cleaners. Add those to Alexa, and my home is becoming eerily similar to the home from "There Will Come Soft Rains."