[quote name='TimR' timestamp='1455878713' post='2983173']
Thanks. I just googled Bluetooth IEM and the latency is 26-40ms!
So are there wifi IEMs- more googling...
[/quote]
Was going to say - latency is the biggest drawback of digital and IEMs. In fact, digital does bring a lot of drawbacks in terms of latency to a lot more than just IEMs. Take your typical digital instrument wireless - that's on average between 3-8ms latency. Into a desk that introduces between 2-10ms (depending upon on the desk) of processing (assuming you are only using onboard processing - external processing adds it's own latency on top)... before you even get that to your ears, worse case, you are looking towards on18ms latency. If you are running a digital snake between the stage and the console... there's more latency.
Now replace your worse case 8ms wireless guitar transmitter for a microphone. Now trying singing against a signal which is near enough 20ms behind what you are singing. It's not a flier. A delay direct into the ear becomes unbearable at 10ms - for other people it's less than that. That's why digital IEM systems are not common place yet... as by the time it hits the transmitter system, you can't afford to add any more latency! This is why there is no mainstream digital IEM. (Lectrosonics (translates to "expensive" are the only guys I know of who make one - and I seem to recall the latency figure being crazy low - circa 1ms). The thing is, the IEM system would get the blame for all the acquired latency up to that point... so it would be a marketing nightmare to try and make even a low latency system work appealing to end users.