Loudspeakers

As we saw with the diminutive C1 [HFN Sep ’25], Børresen’s design priorities are other than achieving a flat or uniform axial response [see Graph 1]. Here the X3 again reveals a mode at the top of the (upper) DCC5’s bass/mid driver’s range [also visible on the CSD waterfall, Graph 2] prior to a 6dB notch centred on the 2.5kHz crossover. This local feature, and the more generalised 3dB increase in output once the RP89 planar tweeter takes over, drives the high ±5.0dB and ±5.3dB response errors, respectively, while the pair matching drifts out to 1.9dB across this same region. Matching planar drivers is notoriously difficult, and though it achieves a creditable 45kHz extension (–6dB re. 10kHz) distortion is a high 3-4% above 8kHz (re. 90dB/1m).

Otherwise, this presence/treble boost ensures the X3 sounds louder still than the 89.2dB (re. 1kHz/2.83V/1m) might suggest. Moreover, it’s important to remember that Børresen specifies a toe-out for the X3, crossing behind the listener, where significant changes in balance can be achieved. At ±15° [blue trace] the response errors fall to ±4.1dB, with a loss in overall sensitivity of ~1dB traded for improved uniformity. Do note that the treble now falls by 6dB between 10kHz and 20kHz but the dip through crossover, and resonances seen on the CSD waterfall, are much reduced. Neither is the X3 a particular challenge to drive – its 4ohm nominal impedance is met with a minimum of 3.1ohm/20Hz, the modulus increasing in trend with frequency, peaking at 20.3ohm/1.55kHz as the reactance of the DCC5 bass/mid unit kicks in. The lowest 1.1ohm/20Hz and 1.5ohm/55Hz EPDR falls outside the bass bandpass. PM