I'd agree with @
themuzicman. Your show, your equipment, your consumables.
Personally, I'd argue that anything under $25 isn't really an
IEM. Through the lack of sound isolation and sound quality I'd expect from something that inexpensive, I'd be concerned that your musicians would be hearing something very different than the sounds their instruments and vocals are actually producing. If all they need to hear and be able to discern is the best of the kick drum, everyday
headphones will get you by. If you need to be able to assess the tonal quality of their
instrument/vocals or other sources, something at that price isn't going to cut it.
Worse yet, a mix-and-match approach to
IEM's is asking for super bad juju. If you have several musicians off of the same headphone amp using their own everyday
headphones (which almost certainly will have no sound isolation), now you've got several musicians who are hearing several different mixes. What one person hears in their Skullcandy over-ear
headphones is going to be drastically different from the musician who's listening through their Apple earbuds that came with their iPod. Not to mention, the guy with the over-ear
headphones is hearing mostly himself and the mix being sent to him, while the person with earbuds is listening to the mix in their ears and every other sound in their geographical vicinity --- but they're both getting the same mix from the headphone amp, so you have to fight with an EQ on that mix that makes both musicians content, an impossible task.
Isolation is key for
IEM's. Like with cheap ear buds, if you have no isolation, you have to crank your mix up above the
level of noise around you if you want to hear your mix more prominently than the brass section to your left and right or the drum kit directly behind you. Without isolation, the
level you have to crank the
headphones up to then is deafening. Literally, deafening -- nothing anyone should be forced to listen to for any sustained amount of time, especially on a routine basis. It will ruin their hearing. Not to mention that for many
headphones, the audio quality will distort at these levels.
Now if your musicians happen to have everyday
headphones that are up to the task, then by all means, invite them to use their own. My everyday
headphones happen to be
Shure SE315's. A coworker of mine has
Shure SE545's as his. A friend of mine has
Shure SE215's. All of these are intended for use as
IEM's and offer >30dB of attenuation for sound isolation with audio quality requiring little to no EQ necessary for achieving a mix representative of the sources being
fed into it. I like to wear my SE315's when I'm working in the scene shop because they provide me hearing protection from all of the saws while also letting me listening to my music at a comfortable
level. They're also designed to be worn for an extended amount of time with inserts of various sizes and materials for the bud material, allowing you to choose the right fit and material for you. That means you can wear these for hours on end without feeling compelled to rip them out of your ears at every available moment because of how uncomfortable they are. My coworker -- he loves his SE545's for when he's on his motorcycle. Again -- they give him ample hearing protection from his bike and from passing traffic, while also letting him listen to music or podcasts or audiobooks at a comfortable, non-deafening
level.
But most musicians aren't going to just happen to have IEM-quality
headphones. A lot of people have never spent more than $20 on a pair of
headphones. That said -- the people who have listened to $250
headphones will almost certainly never turn back. It's a world of difference in sound quality and isolation. Listening to my Apple earbuds or my Skullcandy over-ear
headphones makes me feel like my ears are bleeding -- the quality is just so vastly different, not to mention I can't wear either for very long before extreme discomfort sets in.
If you're going to ask musicians to supply their own, or even if you go out and buy a consistent spread of the same type of
headphones,
really understand the bag of angry cats your potentially opening up. If nothing else, at least buy one pair first, give them a try yourself for 2 hours at a time, clean them off, and then let a couple of your musicians try them out too and give you a yay/nay before you go buying a full inventory of them. After all, your musicians are the ones that will suffer for hours at a time if what you end up buying doesn't suit the application. Not to mention the risk you run of having to then replace them if your musicians can't stand them.
