Loudspeakers

Like any ABR (Auxiliary Bass Radiator), the front-facing unit fitted to ELAC’s AS-61 eliminates port noises that might otherwise result from turbulent airflow, and provides an effective block to the escape of standing wave resonances from within the enclosed air space. Because of the front chamber’s low-pass response, it also reduces distortion from the bass driver and blocks any chuffing noise from the interport. Distortion is further lowered by there now being two bass frequencies at which driver displacement drops (theoretically) to zero, rather than the single null of a bass reflex design. On the downside, there are three LF peaks in the impedance versus frequency response (two with a reflex enclosure) that complicates crossover design [pictured]. ‘All in all it was a very involved system to design,’ says Jones, ‘which required a lot of accurate modelling and simulation to get right.’