With this box, you can have two wireless mics add audio to any show, or karaoke video. Echo effect also great for karaoke. My setup:

* https://www.amazon.com/Epson-PowerLite-Home-Cinema-Projector/dp/B0044UHJWY
* https://www.amazon.com/Onkyo-TX-NR636-7-2-Ch-Network-Receiver/dp/B00IQ0SE22
* https://www.amazon.com/NVIDIA-SHIELD-Gaming-Streaming-GeForce/dp/B01N1NT9Y6

Just unplug streaming device (for me the SHIELD), connect that into the mixer, the mixer into the same spot on the receiver. There's no passive passthrough, you need to have the device on, this does affect multichannel audio, see below. The SHIELD and the Onkyo combo has no delay with this mixer that I could notice, audio and video are synced. With my projector setup, and the output from the mixer going to the receiver, there's no ARC audio return involved, which is the selling point of this device over its predecessor SWM15-HBT https://www.amazon.com/gp/product/B07F8GZVX2. I got this new one in case I want to move the box to a smart TV / soundbar setup, which would be much cleaner with ARC support, I'll update this review when I try it out. I can confirm now that it can do all its predecessor claimed for a full HDMI solution with video from a separate source like the SHIELD or a Roku, outputting to an HDMI receiver, and adds two mics to anything you watch.

The mics are OK, I got these foam covers https://www.amazon.com/gp/product/B019OO4IY6 for them. They connect out of the box once activated. Even if not set too loud they can add echo to anyone's voice and recreate a karaoke bar vibe really well.

The only real drawback is that as far as I can tell this mixer only outputs 2ch audio on the hdmi output. That is, if you have a 5.1 or other surround sound setup, you'll only get audio out of front left and right, you'll lose digital dolby or dts. This is fine during karaoke mode, on my setup, youtube just works in stereo while playing videos and singing into the mics. But when not using karaoke, watching a Netflix show or renting a move in surround, you'll notice you're losing out and only getting stereo. As mentioned if this box had a hdmi passthrough mode when not needing any mixing, and that mode preserved digital multichannel audio, only going to stereo when actively mixing, it would be a perfect device. As it is, if you want multichannel you'll be swapping a few cables around. I'm going to pick up an HDMI splitter and try using two different input modes on my receiver. This should avoid me touching wires, will switch a mode on receiver and one will get multichannel, one 2 channel plus mics, with same video feed. Not sure if there is a viable solution with multichannel using splitters that would work with ARC audio return.

I was looking for a simple full HDMI solution for karaoke for a long time and this is the closest I've found so far. My previous setup was super janky, using a laptop, one wired mic, cables everywhere, not looking cool for the karaoke party guests. This little box is tiny, never moves, the mics just work, on standard AAs, and full wireless is key. This plus youtube app is a perfect karaoke setup, you can set up queues on your phone and cast it to the TV. If you care about surround sound normally you'll be doing some cable shuffling, or getting a splitter, to get it ready. But once set up using the mics themselves is super easy and the setup will look super polished for any karaoke partygoers.

It is a very nice gadget for home kareoke and other applications requiring mixing multiple soun sources with a live stream from a HDMI.
Pros:
1. Great sound mixing features including controlled echo using two wireless microphones (provoded) or your own plugged in mic, or a musical instrument instead combined with an audio/video stream.
2. Sound quality very good for my ear
3. Many connectivity options including audio/video stream from any HDMI device like Chromecast, a DVD player or a PC with HDMI output. Such PC can be controlled by any mobile device to produce the desired kareoke clip. You can also output sound via Bluetooth, ora cable with 3.5mm jack, or using the optical cable.
4. Responsive user support via email ready to assist you with problems you may initially have
Cons:
1 Not easy to use by a non technical person but once some guidance provided by someone who knows and explained, anyone can use the device from then on. This is because of many devices possible to be connected with, and each causing different problems.
2. User manual is very small font hard to read, but it can be found on the net so you can print it in a biger size.
3.Relation to Smart TV is not easy to grasp becaue of variety of Smart TV properties and otions.
4. Potential problems with the microphon output, delayed to an unacceptable level but that was found entirely related to the smart TV (LG) sound processing features which luckily could be bypased after finding the right TV setings thus restoring minimum delay acceptable performance.

I really like that I can finally sing any songs I like directly from Youtube. This thing is great if you love to karaoke. The only thing I dislike about this is that, it drains the mic battery really fast compare to my old Magic sing karaoke. I already replaced it 3 times in just few months since I got it. Be sure you have plenty of extra batteries because you'll need it.

Only thing I can really complain about is the bluetooth microphones they include. I didn't want these, but I couldn't find the product without them. They are as I thought they would be, sub par. You have to have the microphone in the perfect position for it to put up the sound. The range on them is good, and they are battery operated. I don't have any complaints there. It is just the sound goes in and out because it can't pick up sounds outside it's very limited cone. This is just the extra stuff though, the main product. The actual device, I couldn't be happier with. So far it has exceeded my expectations. Great for anyone who wants to do karaoke and already has most of the things you need (except the audio mixing). I used it with a laptop, connected to the device, connected to a TV. Had the sound all going through a sound bar.

I use sonos speakers throughout my house so a basic karaoke machine was essentially just me holding the microphone and not being able to hear myself because I like the music blaring through my sonos speakers. This was exactly what I was looking for and at a great price. I am about to connect these mics through my sonos and tv and I can bang the music and sing along and it sounds great. I definitely recommend these if you have a sonos or some type of surround sound setup and want the mics to be played through that. A MUST HAVE!!!