General
Line 6's XD-V75 TBP12 transmitter allows you plenty of freedom to move about on stage without worrying about signal transference. Just choose one of its twelve channels and a matching EQ setting and you're good to go. You won't be bothered by interference as you and your fellow performers all have different channels.
Digital
This transmitter digitises your sound and sends it to the receiver, which turns it back into an audio signal. Why this conversion, you wonder? The answer is simple: an analogue system can be thoroughly messed up by interference, whereas a digital signal is binary - it has just two set values: 0 and 1. Even if the digital signal is tampered with, there's never enough interference to convert a 0 to a 1 or the other way around. Whatever you send to your transmitter will get there unscathed - the sound is absolutely clean.
