Loudspeakers

Coupled-cavity bass loading enjoyed a brief period of popularity after KEF introduced it in the Reference 104/2 in 1984 (also in the R107 and Two-series models) but we see it infrequently these days. Why ELAC has chosen to revive it is a moot point given that there’s nothing exceptional about the Adante

AS-61’s bass performance – although it does save the need for some crossover components. For its size, and given its 4ohm nominal impedance, the AS-61’s specified 85dB sensitivity looks fair but we couldn’t match that figure, recording 83.4dB on pink noise. This is despite the AS-61 being a moderately challenging load to drive, with a minimum modulus of 3.8ohm and, as a result of quite high LF phase angles, a minimum EPDR (equivalent peak dissipation resistance) of 1.7ohm at 80Hz. Elsewhere in the audio range, though, the EPDR never dips below 3.3ohm.

The forward frequency response, measured at 1m on the axis of the coaxial tweeter shows a slight presence band dip followed by a hump around 10kHz but the response errors are modest at ±3.3dB for both speakers [see Graph 1]. (Ignore the roll-off below 400Hz which is an anomaly caused by the restricted measurement time window.) Pair matching error is poor, though, at ±2.2dB over the same 300Hz-20kHz frequency range. Some justification for the low sensitivity is found in the bass extension, which diffraction-corrected nearfield measurement showed to be 46Hz (–6dB re. 200Hz). But the nearfield measurement also revealed a peak of about 5dB at 170Hz, apparently due to the acoustic low-pass filter being underdamped. The cumulative spectral decay waterfall [Graph 2] is mostly clean but for two modes associated with the 10kHz response hump. PM

Sensitivity (SPL/1m/2.83Vrms – Mean/IEC/Music): 83.7dB / 83.4dB / 83.2dB
Impedance modulus min/max (20Hz–20kHz): 3.8ohm @ 95Hz / 29.3ohm @ 33Hz
Impedance phase min/max (20Hz–20kHz): –63° @ 66Hz / 40° @ 20kHz
Pair matching/Response Error (300Hz–20kHz) ±2.2dB / ±3.3dB/±3.3dB
LF/HF extension (–6dB ref 200Hz/10kHz): 46Hz / 37.2kHz / 24.6kHz
THD 100Hz/1kHz/10kHz (for 90dB SPL/1m): 0.5% / 0.2% / 0.5%
Dimensions (HWD): 484x244x402mm
Price: £2600