Wifi receiver transmitter kits

I have used these (both transmitter and receivers) in the past with no issues whatsoever. No snake oil here! They do what they’re supposed to do, and they do it very well without any audibly noticeable loss and with a flawless uninterrupted wireless connection.

I’ve recommended these to others that did not want to have to run wires to their rear speakers and even to an adjacent room and building and they all have been happy also.

Do stay away from Bluetooth. With Bluetooth you will lose A LOT of fidelity.

DW 20T Wireless Audio Transmitter - Sweetwater

Klark Teknik DW 20R Wireless Audio Receiver | Sweetwater

raphaz You only need one transmitter and one receiver for 2 speakers as long as you have long enough cables to go from the receiver to each of the speakers. One for the left channel and one for the right and you can place the receiver somewhere in the middle. 

You may need adapter plugs to go from whatever type of output your source has (XLR, RCA, 1/4") to the transmitter, as well as whatever type of connections your speakers have to connect the receiver to the speaker's inputs.  Those are cheap!

As far as apps, there is no app.  They are independent units that communicate at 2.4 GHz from the transmitter to the receiver.  Similar to wirelessly connected microphones, guitars, etc.  

I don't have an opinion on Wiim Mini.  I've never messed with those, but I can tell you that there is no substitute for full size audio components if you are concerned with fidelity.  I like all my stuff wired!