Loudspeakers

Here's something unusual: a high sensitivity loudspeaker that delivers on its specification! Paradigm claims 93dB sensitivity for the Paradigm 9H, very close to the pink noise figure of 93.3dB SPL at 1m for 2.83V input that our testing recorded. Our 'music' figure is close too at 92.8dB, but that 0.5dB disparity hints at a less than flat on-axis frequency response, confirmed by the measurements we obtained at 1m on the tweeter axis [see Graph 1, below]. (Ignore the roll-off below 400Hz which is a measurement artefact.) A presence band suckout is followed by a treble peak at around 10kHz, the two resulting in quite large response errors of ±4.5dB and ±4.4dB. Listening a little off-axis would help quell the 10kHz peak. Pair matching error over the same 400Hz–20kHz frequency range is ±1.1dB but the anomalous LF roll-off plays a part in this, for from 600Hz to 17kHz we recorded an excellent ±0.5dB.

The price of the high sensitivity is low impedance. Paradigm is another manufacturer trotting out 'compatible with 8 ohms' rather than a proper specification of nominal impedance, and it's easy to understand why: the 2.4ohm minimum modulus we measured means that the 9H is nominally a 3ohm speaker. And it has an EPDR (equivalent peak dissipation resistance) which drops to a scary 1ohm, albeit at 9.7kHz where its effect will be ameliorated by most music containing relatively low signal levels. More relevant is the dip to 2.0ohm at 413Hz, which is actually a little higher than we measure from many modern speakers. Bass extension is prodigious with its –6dB point (re. 200Hz) actually dipping below 20Hz. Finally, the CSD waterfall [Graph 2] shows a treble resonance at around 5.5kHz. KH