The best monitor for sound in our tests is the Philips Avent SCD630, with a score of 8 of 10. This monitor has the best sound activation and background cancellation features in the group, and while the sound is bright, it is also clear without an echo. Most of the competition earned 4s and 5s for sound, with all of the Wi-Fi monitors only earning 4s. It seems that no matter how good your parent device might be, the Wi-Fi cameras struggle for the most part to transmit clear sound with good sound features.
If your internet goes down, your baby monitor goes down. A wifi baby monitor uses your home's internet connection to communicate to servers, then to your app. So if your internet connection goes down, then you will no longer be able to stream video of your baby. That's a huge consideration to keep in mind because you never know when your internet will slow down or simply stop working for several minutes or hours, and you will be stuck without a working baby monitor. There are a few wifi baby monitors that will still communicate locally (within your home's network) when the internet goes down, such as the Lollipop or Nanit. They do this by switching from internet to local area network when an outage is detected, so you can have confidence that if you're connected to your home wifi you'll still see your baby.
Most dual monitors come with split- or even quad-screen viewing, and the DBPower Digital Sound Activated baby monitor does just that. This model supports up to four cameras, allowing you to monitor four rooms at once. With features like remote pan/tilt/zoom, room temperature monitoring and alert, two-way communication and manual or automatic video recording, we found the DBPower to be the best dual baby monitor.