Some time ago, I needed an interface for making multi-channel audio recordings. Cost was a major factor, and I needed at least 16 microphone channels. After researching many options, I decided to get a Behringer X18 digital mixer. This was the most cost-effective digital mixer available at the time. It supports recording up to 20 channels, which include all channels plus the LR mix, via USB to a PC or Mac and an ASIO driver.. The 16 mic inputs support XLR and quarter-inch plugs, balanced or unbalanced. Inputs 1 and 2 support high-impedance devices such as guitar pickups.

The XR18 has the same functionality in a more compact, stage-friendly chassis, but the X18 was significantly cheaper, and its chassis works for me, as I am used to having my mixer on the table where I work during recording sessions, and the tablet that may be used as the interface does not have to be mounted in the space provided for it. The only functional difference between the two mixers is that the X18 uses TRS sockets for the Aux Outs while the XR18 uses XLR sockets, and the Aux inputs on the X18 uses RCA jacks while the XR18 uses quarter-inch phone jacks. There are adapter plates available for rack-mounting the XR18.

The XR18 has a small fan for cooling, while the X18 depends on unaided airflow. This means that the X18 is more sensitive to heat and should not be left on for long periods of time, say 6 to 8 hours or more, depending on ambient conditions. To overcome this possible problem. I purchased an inexpensive and silent cooling fan and placed it on one side of the mixer so that it blows cool air across the underside of the mixer. I recommend this approach.

As I write this, the X18 has limited availability, being replaced by the XR18 due to its popularity and possibly by the heat sensitivity of the X18. The information supplied below applies equally to the XR18 mixer.

The primary downside of this type of mixer is the lack of faders and physical controls. The user must be comfortable with using a computer or tablet to operate the device, and with the limitations of using such an interface. A touch screen is not as responsive as a physical interface. I sometimes find that I have to make a couple of attempts to move a fader on a tablet or phone, but a physical slider always responds immediately. It's somewhat easier to be precise with a physical control than with a touch screen. The Behringer does have a Fine setting that helps improve precision - however, one must engage that option. I prefer to use a mouse with the PC interface for these reasons. Some details about this follow.

In doing sound for theatrical performances, I find that I tend to focus on the PC screen a bit more and less on the stage action. This means that I must know the vocal cues for changing settings on the PC, not the visual actions on stage. This is less of a problem with a mixer that has actual sliders and controls. However, a digital mixer that has motorized sliders and the functionality of the X18 costs 4 times as much as the X18. This is out of my price range by a long shot.

That being said, I have been amazed at the functionality of this little mixer and the design of the PC interface. White I prefer to work with a PC, the tablet and phone interfaces are certainly very functional and can access all functions of the mixer. For example, when getting ready for a theatrical performance, it is very helpful to be able to go to the dressing room or backstage with my phone or tablet to do mike checks, or to stand in various places in the performance arena to make adjustments during sound checks. (Of course one can also do this with most digital mixers that have standard mixer physical controls.)