This device looks like a nice and affordable in-ear monitoring device, but in practice it isn't useful at all.
We tested the device extensively in the hangar and in the RF-lab, which can be made RF free.
Findings in the lab: the frequencies of the transmitter and receiver are dramatically tuned (probably a bad locked PLL in the beltpack), so there is always a RF hiss present. Some channels are a kind of hiss-free, but only with an "optimised" position of the receiver. And that's not the idea of a wireless system..
Also gave it a try in the rehearsal room and on stage, but we better kept it in the case...
Other products from LD Systems we tested (e.g. wireless mic's) were promising, but this wireless device unfortunately is nothing but a disappointment..
M. Weskin
Electrical Engineer (Analog electronics & RF expert)