The midrange of the Blue Hawaii SE is also quite natural. Essentially, all headphones have some frequency response errors that lead mid- and upper-range instruments to sound a little distorted, especially on certain dynamic passages. The SR-009s reduce these distortions significantly when compared to many headphones, but they can, at least with some amplifiers (e.g., the Woo), occasionally over-emphasize upper midrange transients to a slight degree. We thought the Blue Hawaii SE did an excellent job of taming this tendency of the SR-009s, in the process showing just how neutral and smooth-sounding the SR-009s can really be.
In a sense, we are talking about ways in which different amps manage and balance sonic qualities that, while positive in an abstract sense, also have the potential to become double-edged swords. If we look in more detail at the upper midrange and treble performance of the Blue Hawaii SE as compared to the Woo WES (with upgraded tubes), several things become apparent. First, the Woo conveys an almost otherworldly quality of purity and continuousness, and gives the impression of offering almost boundless reserves of resolution and detail. For listeners who highly prize those specific qualities, the Woo may be the amp of choice. Second, the Blue Hawaii SE has an absolutely uncanny ability to capture the constituent elements of music in a subtle and revealing way (not quite as microscopically revealing as the Woo, but close), while at the same time—and this is hugely important—showing how those musical elements combine to form a cohesive whole. Thus, the Woo tends to deconstruct music into its component parts, while the Blue Hawaii SE reveals the parts but deftly reconstructs them to present a musical whole that makes sense.
Interestingly, planar drivers often have a bit of resonance in their measured decay patterns, so in the unlikely event that you encounter moments when the Blue Hawaii SE/SR-009 combo does sound a tiny bit rough-edged (a very rare occurrence), we can’t help but wonder if the BHSE might actually be more revealing than some competing amps. This question comes to mind because of the excellent small signal accuracy shown by the Blue Hawaii SE. Small signals are important as the basis of spatial presentation because they are what you hear