Loudspeakers

Measured midway between the TZ2900 horn tweeter and 160mm paper midrange cone or, indeed, directly on the horn's axis, the Magellan Cello's forward response shows a ~5dB dip in output at 1.5kHz [Graph 1] that's also reflected in a mode on the CSD waterfall [Graph 2]. We saw similar in the Alpha Signature [HFN May '15], possibly due to a mistermination at the mid's pleated surround. Either way, this is at the top of the mid unit's 350Hz-2.5kHz range before it crosses over to the (phase inverted) tweeter, and it contributes to the ±4.1dB and ±4.0dB responses errors alongside the ~6.3dB dip in output at 16.3kHz. The latter is just prior to the magnesium tweeter dome's primary resonance at 24kHz. These dips aside, the trend falls within far 'flatter' ±1.7dB limits, while the pair matching is a tight 0.6dB (all re. 200Hz-20kHz). The effect of the grille is particularly disruptive through mid and presence [blue trace, Graph 1] suggesting it should always be removed before 'serious' listening.

The 90.8dB/1kHz sensitivity meets Triangle's 90dB spec. but dips slightly to 90.3dB over a more representative 500Hz-8kHz range. Triangle's ambitious –3dB/35Hz bass claim is supported by those two 160mm 'sandwich' bass cones but their 57-230Hz bandwidth (–6dB), supplemented by a vigorous 32Hz port tuning, actually brings the extension in closer to 50Hz (–3dB re. 200Hz, or 32Hz/–6dB). This is still impressive, and achieved with ±50° swings in impedance phase through the bass and a sub-4ohm load from 85-350Hz, although the minimum 1.3ohm/89Hz (sub-4ohm, 68Hz-1.3kHz) EPDR is not especially tough for the sensitivity and bass extension on offer here. PM