There are a few points I’d like to address. First, performing with in-ear monitors without rehearsing with them first is a bad idea. One needs to learn how to use them just as much as one needs to learn how to use microphones, or stage monitors, or teleprompters, for that matter. There is a discovery process and one must try things out and adjust in some ways that may not be obvious or intuitive. If you’re in a group, you may want to discuss and share your personal discoveries, getting the benefit of everyone’s ideas and making the adjustment process quicker and easier.
Second, there are two components to IEMs. First is that you’re plugging your ears with something you’re probably not used to. Second is the wireless component. Those are separate concerns and bring up different challenges. The wireless interference has nothing to do with the quality of the IEMs themselves. It’s the transmiters and receivers that must be working well. If your battery pack is not fully powered or if there is electromagnetic interference, the wireless reception may be undependable. Don’t blame the monitors in your ears. Blame the wireless pack on your belt (or the one on the rack somewhere in the auditorium, or perhaps the police radios that are driving by the venue).
Now, what about the quality of the IEMs themselves? We’ve all had the experience of listening to music on different sets of headphones. Some sound better than others. Some sound truer than others. Some are more comfortable than others. All of these will be true about IEMs, as well. I did research a few years ago and could find no single source for good cross-vendor comparisons of IEMs. I happened to get some Shure middle-of-the-road single-driver monitors (because the group was getting them as a package deal), and they were pretty good. Not great, but good. Bass response was especially lacking, which was bad news for me as the bass vocalist. Keeping the physical sub-woofer in the stage setup helped a lot, though. However, the decision to get those was based more on the brand and the price range than on any technical details or independent evaluations. I’d like to see someone get some really good specs on all of the top lines and put them together in a good spreadsheet or table.
Now I’ll get to the main point for you all to consider. If you’re placing foam or rubber “general use” sleeves into your ears, you’re losing a LOT of the value of IEMs, in my experience. Whatever you do, whatever you purchase, make certain that it includes a customized in-ear silicone sleeve. That means you have to have someone (an audiologist or ear professional) to squirt some special gel into your ears and custom-fabricate a sleeve for the IEMs. Yes, that is an extra cost, but trust me, it’s a huge added value, no matter what IEMs you’re getting. If they don’t have that capability, move on and keep shopping! And make sure it’s silicone. Hard plastic is not as good. Silicone is more comfortable and more durable. And it doesn’t change its composition or feel, even after years of sweaty use.
My Shure IEMs were only so-so when using the rubber or foam inserts. About on par with Apple ear-buds (which suck, so don’t even consider using those on stage). But with the customized silicone sleeves the Shure monitors were my tool of choice for listening to music unless I was in a recording studio. They even work great on an airplane, since the sleeves cut out all outside noise (I didn’t have the ambiant feedback feature, as mentioned in the article above). I compared them with some Bose noise-cancel headphones on a noisy plane flight and the effect was almost exactly the same, except that my IEMs didn’t require any internal batteries and they were much more comfortable. Once you get used to having something IN your ears, the silicone allows you to avoid the overheating of over-the-ear headphones, and they’re a lot more compact to carry.
Unfortunately, mine were stolen (along with some prescription glasses – neither of which would be of any use to ANYONE else!). So now I’m actually shopping for replacements, myself. Anyone have that independent specs / comparison chart I was suggesting?