This has expanded my surround system and made the rear and side channels very stealthy using ghost speaker wire, even working through a wall as advertised. Highly recommend.

I ordered 2 of these for my rear surround speakers and an 800 model for my powered subwoofer. One of the 880s was going in and out with the sound so after messaging the company, they had another one sent out. There is a small high pitched buzz in the new one that was sent out but you don't notice when sound is coming through. You have to get close to the speaker when nothing is playing to really notice it.

I also used my own wiring instead of the little wire that came with it as my speakers have banana bindings on the back. I tried troubleshooting the high pitched buzz by attaching the amps to the opposite speaker/wiring and the high pitched buzz was heard in the other speaker so I know that it is the receiver itself. When switching back to my original configuration, the buzz went away but came back a day or so later. As I mentioned, the high pitched frequency is pretty small so I didn't find it annoying enough to complain about.

Overall this works pretty good. I live in Philadelphia which I feel should be mentioned as I've seen some comments about needing to live in a rural area for these to be useful. I don't use the volume control on the back and turned it down pretty low as i used the YPAO configurator on my receiver to handle the volume output. I took a star off because the construction of the actual device seems pretty bulky/cheap for the amount of money that it costs. I'd much rather see these priced at $30-$50 but the company obviously has something here as it was pretty easy to set everything up. Also I thought it might be worth mentioning to make sure you have the wiring hooked up and the adapter plugged in to the back of the receiver BEFORE plugging the adapter into the outlet. You'll notice some sparks with both the wiring and the adapter otherwise.

The system works great as compared to a previous wireless solution that I tried. The system/receivers took a little adjustment with regard to positioning and audio levels. I found that the receivers appear to work better/have better signal reception if they're secured vertically (up & down) as opposed to horizontally (flat and level), most likely due to the signal polarization from the transmitter. I recommend buying some self adhesive Velcro and attaching it the bottom of the receiver and the back of the speaker. I occasionally have to re-sync the transmitter/receivers but only after several weeks of use and I'm assuming other wireless interference.
The only reasons I'm not giving it five stars is that I did have to purchase a replacement receiver unit within a could weeks because the original was not receiving a sustained signal. Not matter the positioning, re-syncing, or proximity to the transmitter the receiver would start to 'burp' and would intermittently cut in & out, which was very noticeable with a 7.1 surround sound system. Lastly, when plugging and unplugging the AC power connector into the units; there is a very noticeable amount of 'sparking.' I don't think it's dangerous, but it is a little disconcerting the first time I connected and disconnected the units.

The Amphony R880 receiver, used in conjunction with T800 transmitter, does what it is advertised to do. When comparing this to the Amphony 1800 kit, the R880 seems to be a much better unit for a number of reasons: the sound quality is better to my ears; it has greater reception range; a total of four additional receivers, thus up to four additional speakers can be used where the 1800 kit allows only two. The last reason allows one to create a wireless 5.1 or a 7.1 surround sound system, assuming that one already has an audiovisual receiver (AVR) system and a subwoofer.
Product support through the vendor "HiFi Corner" is outstanding! If you should have a question about what unit to buy, or how to use it "HiFi Corner" is ready and able to assist you.

I bought two of these receivers with a transmitter for the rear speakers in my living room. I also bought a Sony 7.2 Channel Home Theater 4K AV Receiver (STRDH770) to replace an older Sony receiver. It was all a birthday gift. When everything was initially setup one receiver would pick up sound and the other had almost no sound at all. We worked with the manufacturer and they quickly did an RMA on the units thinking that something might be wrong. (Great customer service by the way). They tested a set before shipping out to us but they did the same thing. We were about to give up and submitted a return requesst when the manufacturer suggested getting "Cutequeen 2PCS 100W Watt 50 Ohm Aluminum Case Wirewound Chassis Mounted Resistor (pack of 2)" to try. It turns out that the Sony Receiver is trying to be smart and detect the impedance of the speakers and just disabled them when the Amphony transmitter didn't provide enough impedance. Adding the resistors tricked the Sony into putting out sound. The product works really well once you add that resistor and the manufacturer was really responsive. I only took a star off because of the inconvenience when it was a birthday gift.