Loudspeakers

The A4t’s high 90.8dB sensitivity is boosted by the generalised 1.5dB uplift from 800-1.5kHz, but this falls to 89.1dB (500Hz-8kHz) – still higher than Perlisten’s own 88.6dB specification – as a result of the speakers gently declining mid/treble trend [see Graph 1]. From 1-20kHz the axial output falls by ~3.5dB but the response is largely free of irregularities, as evidenced by the short decay of any modes seen on the CSD waterfall [Graph 2], and the errors of just ±2.3dB. Two 35mm treble dome resonances are visible at 28kHz and 42kHz [pink shaded area, Graph 1]. Pair matching is a very tight 0.4dB up to 10kHz but slackens off thereafter to 2.0dB, but this will not have any significant effect.

More importantly, listen slightly off-axis [blue trace] and the declining mid/treble trend becomes more obvious – a drop of 10dB from 1-20kHz. Even if you are listening bang-on axis, the reflected sound lacks treble, suggesting this big box may still sound a little ‘lost’ in big rooms or if used too far from side walls. This, of course, may be a deliberate ploy by Perlisten to improve its ‘big box compatibility’ in small rooms...

The slot port, meanwhile, is tuned to a very low 15Hz albeit with significant output to 120Hz (–6dB) followed by a series of modes up to 200Hz. The top and middle woofers have an extended bandwidth to 1.3kHz, the lower working below 250Hz, the diffraction-corrected total yielding a 34Hz bass extension (–6dB re. 200Hz). Perlisten rates the A4t as a 4ohm load, and the 3ohm impedance from 100-300Hz certainly reflects this. There’s a dip in EPDR to 1.6ohm/77Hz, near a dip in impedance phase, but the toughest 1.2ohm appears at a higher 420Hz. PM