Westone opened its doors in 1959. In the beginning it made custom molds for hearing aids. It wasn’t until the 1990s that Westone began to adapt its hearing-aid-related technologies to in-ear monitors for musicians and sound professionals. By 1995 Westone was collaborating with Van Halen sound technician Jerry Harvey to create Ultimate Ears. Since then Ultimate Ears and Jerry Harvey have gone on to create their own in-ear monitor brands, but Westone has continued to innovate with multi-driver designs and state-of-the-art production and testing facilities.
Up until recently all of Westone’s products were made in its Colorado Springs facility (which I visited and documented in Issue 263). In its nine separate production studios Westone produces not only custom in-ears, but also the UM line of universal in-ears, military earpieces, and hearing-aid products. But the W Series models, which include the W10, W20, W30, W40, W50, and W60, are manufactured in China under Westone’s supervision.
The Westone W60 ($999) is the second from the top model of the W Series, which now also includes a W80. It is a six-driver system with three crossovers; two drivers each are used for the treble, midrange, and bass. As with all Westone designs the driver technology is balanced armature. The W Series drivers are custom made for Westone by Knowles, the largest independent manufacturer of balanced armature drivers in the world.
Before we delve into the specifics of the W60 I think it would be a good idea to review the basic technology behind it. The primary “building block” of the W60 is a balanced armature driver. A balanced armature uses a pair of magnets with a movable reed situated between their magnetic fields. The reed is connected to a drive rod that is attached to a diaphragm. A signal sent to the magnets moves the reed, which moves the diaphragm. The diaphragm itself is housed in a sealed enclosure with a tube at one end. This driver mechanism requires less power than a dynamic driver because it is a much more efficient transducer. In many ways a balanced driver resembles a miniature compression driver. Like a compression driver, the increased velocity at the armature’s throat moves air more efficiently than a dynamic driver can. And like a compression driver, most balanced armatures are not full-range transducers (some single-driver balanced armature designs are relatively full-range). Instead most are linear within a limited frequency range, which is why the “best” balanced armature designs employ multiple drivers to cover the entire audible spectrum.
Crossovers for multiple balanced drivers can be “active” with distinct high-pass or low-pass filters, or they can be “passive” where the native attenuation and roll-off of the drivers are used to combine drivers without additional crossover components. Both methodologies have their advantages and disadvantages. Keeping phase consistent through the crossover regions can be a problem for either methodology.
The Westone W60’s crossovers use a “simple” first-order 6dB-per-octave slope combined with the natural roll-off of the balanced drivers to achieve a smooth transition with minimum phase shift. Karl Cartwright, one of Westone’s principal designers, calls the final bit of crossover tuning “acoustic trickery” in that it uses the combination of first-order crossovers and tuning to achieve Westone’s characteristic frequency curve.
Karl was also responsible for something that he calls “the lip test.” This test involves moving the plastic casings of Westone monitors around on his lip to see if there are any rough spots or seams that could reduce the overall comfort of the housing. You can, if you wish, try this at home with your favorite in-ear monitor. If it is well constructed, there should be absolutely no rough spots or edges that you can feel. And why the lips? They happen to be among the most sensitive spots on your body you can access in public without being arrested.