Sonus faber Electa Amator III Loudspeaker Lab Report

Lab Report

A benefit of the Electa Amator III having a straight-sided rather than curved-sided cabinet is that internal volume is maximised, helping achieve the best combination of sensitivity and bass extension for its compact exterior dimensions. And an impressive combination of the two is exactly what this speaker achieves. Sonus faber specifies 88dB SPL at 1m for 2.83V input and our measured pink noise figure of 87.7dB justifies that. This is bought at the expense of low impedance, however. Sonus faber's nominal 4ohm is entirely consistent with our measured minimum of 3.3ohm but low frequency impedance phase angles are quite high, as a result of which the EPDR falls to a minimum of 1.6ohm at 116Hz. While this is pretty typical of modern loudspeakers, a second dip to 1.9ohm at 610Hz makes the Electa Amator III a tougher than average amplifier load.

Forward frequency responses [Graph 1, below], measured at 1m on the tweeter axis, show a clear presence band dip and rising high treble output thereafter which will almost certainly make the on-axis sound too bright – but listening a little off-axis will cure this. Because of the treble rise response errors are on the high side at ±5.1dB and ±5.4dB, respectively, but should reduce off-axis. Pair matching error over the same 200Hz-20kHz frequency range is fair at ±1.2dB, but is an impressive ±0.4dB from 200Hz-10kHz for all but one very narrow band. Diffraction-corrected nearfield measurements show the bass extension to be 42Hz (–6dB re. 200Hz) which is a good result given the generous sensitivity figure. The CSD waterfall [Graph 2, below] shows some low-treble resonances almost certainly the result of bass-mid driver breakup. KH


Forward response indicates a depressed presence band relative to a rising (high) treble


Cabinet modes are mild but the driver resonance at ~4kHz also appears in the freq. resp.

Sensitivity (SPL/1m/2.83V – Mean/IEC/Music) 90.0dB/87.7dB/86.6dB
Impedance modulus: minimum & maximum (20Hz–20kHz) 3.3ohm @ 213Hz, 28.5ohm @ 83Hz
Impedance phase: minimum & maximum (20Hz–20kHz) –63° @ 94Hz, 49° @ 30Hz
Pair matching/Resp. error (200Hz–20kHz) ±1.2dB/ ±5.1dB/±5.4dB
LF/HF extension (–6dB ref 200Hz/10kHz) 42Hz / 38.0kHz/37.5kHz
THD 100Hz/1kHz/10kHz (for 90dB SPL/1m) 0.6% / 0.5% / 0.2%
Dimensions (HWD) / Weight (each) 375x235x360mm / 14.6kg
Price £9000

Sonus faber SpA (Fine Sounds Group)
Supplied by: Absolute Sounds Ltd
0208 971 3909