System Audio saxo 40 Loudspeaker Lab Report

Lab Report

Unless you are slumped into a beanbag the nominal listening axis for the saxo 40 will be above the top of the cabinet, the off-axis uniformity of the T25DXT Ti tweeter being aided by System Audio's peripheral DXT acoustic lens. Measured a few inches above the tweeter, the saxo's forward response shows a gently declining output from the two W1408 bass/mid units up to the 2.2kHz crossover [Graph 1], after which there's a peak in output at 4.5kHz in one of our pair, possibly supplemented by an out-of-band resonance from one of these same drivers [CSD waterfall, Graph 2]. Above 7kHz the treble is well managed, extending to a creditable 34kHz (–6dB re. 10kHz). The overall response uniformity is a good ±1.8dB and ±1.7dB, respectively, but not for the first time we have SA speakers whose pair matching (1.7dB) is influenced by an irregularity in one sample – here between 4-7kHz. Either way, the grille (white or black!) introduces a deep –8dB cancellation notch at 5.6kHz [blue trace, Graph 1].

Bass is good to 65Hz (–6dB re. 200Hz) thanks to the identical 79-420Hz bandwidth of the two drivers, supplemented by the broad 50Hz tuning of the rear port. Deeper bass is achievable as you experiment with speaker placement near, but not too near, rear walls. The 87.3dB sensitivity is below SA's rated 89dB/1kHz, and the more representative 500Hz-8kHz average of 86.6dB is lower still, but this might be expected for a box and drivers of this size. Moreover this is offered without imposing too harsh a load – a min. impedance of 4.3ohm/190Hz but a tougher EPDR of 1.7ohm, partially mitigated as it occurs at a higher 3.9kHz after a big swing in impedance phase of –59° at crossover. PM


Response inc. nearfield summed driver/port [green], freefield corrected to 1m at 2.83V [yellow], ultrasonic [pink]. Left, black; right, red; w grille, blue


Resonance correlates with peak in response at 800Hz [see Graph 1] and driver modes at 2-5kHz

Sensitivity (SPL/1m/2.83V – 1kHz/Mean/IEC) 87.3dB / 86.6dB / 84.8dB
Impedance modulus: minimum & maximum (20Hz–20kHz) 4.3ohm @ 190Hz, 29.6ohm @ 96Hz
Impedance phase: minimum & maximum (20Hz–20kHz) –59° @ 2.5kHz, +44° @ 83Hz
Pair matching/Resp. error (200Hz–20kHz) 1.7dB/ ±1.8dB/±1.7dB
LF/HF extension (–6dB ref 200Hz/10kHz) 65Hz / 33.3kHz/33.6kHz
THD 100Hz/1kHz/10kHz (for 90dB SPL/1m) 0.7% / 0.25% / 0.65%
Dimensions (HWD) / Weight (each) 845x165x250mm / 12kg
Price £999

System Audio A/S
Supplied by: Karma-AV Ltd, York
01423 358846