So, we can start with the one that was raised with @mathsjunky in private messages: individual analogue outputs from the desk.
This is, naturally, limited to the number of outputs (specifically, busses) on the desk. A lot of older analogue mixers only have 2 or 3 busses that can be used for monitoring or āfoldbackā. Some of the newer digital mixers, like the XR18, have more. The XR18 has 6.
You can either use these with traditional wedge monitors (which is how we started out using the XR18 when I was doing the band sound) or into individual IEM feeds. This could be, for example, into a central IEM transmitter unit.
Note that these outputs are line-level balanced output. They wonāt drive speakers or headphones directly. They are also mono.
If you use them to feed wedge monitors, these need to be powered monitors.
For individual wired IEMs, you will normally require a small analogue amplifier/headphone amp on each of the outputs to connect the IEMs into. Something like the Behringer P2 should do the trick.
Now, for each of the outputs, youāll need to create a monitor sub-mix. For wedge monitors, you would normally do this the traditional way, by the sound-guy creating the monitor mix.
For IEMs, you could have this centrally controlled or, with modern digital mixers, thereās often app control. So it is possible for individual IEM users to run an app on their phone or tablet and control the mix on specific outputs.
When I was doing this stuff, I used to use the official Behringer X-Air app on my tablet and this could be configured with custom screens for individual channels. But that app seems to be deprecated now.
Now, for the XR18 (on Android) thereās MX-Mix, which is the official Behringer app, and Mixing Station, which is a third-party app. There may be others. I should point out Iām not personally used either of these.
With one of these apps and some customisation it should be possible to present each channel user with a phone-based interface which they can use to control the mix. They could then have the phone on a nearby mic stand or similar. To make it useful they would need to disable screen lock and, possibly, the screen timeout.
The main limitation of this approach is that you will be limited to the number of busses on the mixer. If your band has more band members than you have busses, they you either cannot give them all IEMs, or youāll need to split one of the bus outputs and some people will need to share a mix.
The XR18 has 6 bus outputs which is probably enough for a lot of bands.
The other drawback of this, compared to the Ultranet/P16 approach, is the lack of physical controls: it may be fiddly for some performers to make adjustments on a small touch screen mid-performance. The P16s have physical controls which are probably easier to reach up and quickly tweak during a performance.
Cheers,
Keith