Speaker Specs

[Mollengijs]

There is a quirk of loudspeaker design that to achieve higher efficiency often leads to lower impedance, all things being equal.  So although the  93dB efficiency speaker should louder for a given amplifier volume setting, it may actually be harder to drive due to the lower impedance.

The key points though are that these manufacturer figures are notoriously unreliable and will tell you nothing about how the speakers will sound, and in particular the 4 ohms figure will not tell you if there is a impedance 'dip' in the frequency curve that could upset a Devialet or many other speakers.

I think in summary that these figures do not actually tell you that much!  Although @Mollengijs words are absolutely correct, in theory at least.

Thank you for explaining this further. I totally agree. I own Audio Physic speakers and all of the reference line speakers have the same impedance and sensibility (89 DB / 4 ohm) but they are different beasts and different loads to drive because the way they dip below 4 ohm. The Virgo dips the least to ~3,6 ohm and the Cardeas the most (~3,2 ohm). Luckily all well above the 2 ohm mark and they all sound wonderfully with Devialet.