System simplification ideas ...

[Marcello]

@Marcello Just made a search on Amazon and could find a bunch

Hi, I use the Swissonic Converter AD 24/192, paid 35,00 EUR. I tried an even cheaper one, but this sounds better and you have a 24/192 output, that sounds crisper.
Also, the ADC in itself doesn't really correct the latency, it could even add some latency. What you can do on the receiver side to correct latency is add distance between speakers, if your receiver allows this kind of configuration, you should increase the set distance between speakers. 

I think if you place your other speakers around 20m far from the pair of reactors on the receiver configuration, you fix the latency issue completely, because the sound would reach the reactors the 60 ms sooner than the other speakers. My receiver unfortunately just allow 9m distance between speakers at max. therefore I still have this latency that sounds like a small echo, like if I was listening to music in a large empty room. If I didn't add these 9m correction on the receiver side and config the reactors and the other speakers at the real distance, then the latency would be a issue even for multichannel  movies I suppose. So it's really important that you can add some latency to the other speakers to compensate the reactor minimum latency. Around 20m is the sweet spot that matches the 60s latency.

I don't know of any cheap and uncompromising piece of equipment that would add latency, but if you find anything like that, it would correct the other speakers to match the reactors, but still latency will be a issue for Karaoke (because we can't add latency to our heads listening our own voice :-)