The Swingle Singers are a five-time Grammy award-winning vocal group who regularly tour and perform live around the world, flying everywhere with their own microphones, IEMs, and mixing console for their complex live looping show. The goal of this project was to replace a heavy 40kg rack for their in-ear monitors with a two-part carry-on luggage rack with new Sennheiser 2000 series IEMs and an Audio-Technica MCB4 IEM combiner, fitting into two Pelican iM2500 Storm cases.


Pelican iM2500 Storm cases cannot quite accommodate 3 rack units (3U) in height, since their wheels are partly set into the case so limit the maximum depth. However, they can accommodate a height of 3U on the other side of the case. We decided to build two L-shaped cases, each 2.5U in total, and each containing one IEM combiner and four IEM transmitters. The remaining space would then house the directional antenna, along with power and BNC cabling.

The two L-shaped cases can then slot together; bolts sit in corresponding offset holes to ‘lock’ the cases into place, with some Velcro to provide extra protection against vibrations onstage or accidental knocking. The two cases can stick together to be transported in hold luggage in a larger checked luggage case if desired.

For the build itself, we chose to use 1.5mm steel, with a 70 micron powdercoat for resilience. The manufacturing itself was outsourced – CAD files were drawn up and the metal was lasercut and bent; the whole unit was assembled then powdercoated at a separate shop.

The IEMs have been touring since April 2016 and have already successfully been used in dozens of concerts in the Americas, Asia and Europe.

  • Design.
  • Hugh Walker: Concept, co-design, CAD, assembly