Franco Serblin Accordo Goldberg Loudspeaker Lab Report

Lab Report

The latest Accordo's increased cabinet volume and a larger 180mm bass/mid driver bring with it performance dividends over the smaller model [HFN Jan '18]. Although both Accordos are rated at the same 87dB/1m/2.83V, the Goldberg is markedly more sensitive, not least because the uplift in response from 600Hz-1.2kHz [see Graph 1, below] boosts the 1kHz figure to a generous 88.8dB. The gentle dip in upper midrange reduces the averaged (500Hz-8kHz) figure to 87.8dB but this still bests the brand's conservative spec. The response recovers above 4kHz but a peak at 9kHz and dip at 300Hz both contribute to slightly high ±4.1dB and ±3.8dB response errors, respectively, though pair matching is tight at 0.6dB over the same 200Hz-20kHz. The elastic grille is not entirely invisible, exaggerating the peaks from 6-10kHz [blue trace, Graph 1] but offers no further attenuation of the soft-dome's gentle 25kHz HF roll-off (–6dB re. 10kHz).

A driver mode is seen on the CSD waterfall at ~5kHz [Graph 2] but THD is low enough at 0.2-0.5% from 400Hz-10kHz at 90dB/1m – the increase to ~1.5% at much lower frequencies not unexpected for the enclosure/driver size. The latter has a slightly peaky reflex alignment at 96Hz but operates over a wide 66Hz-1.3kHz bandwidth, extending to a diffraction-corrected 47Hz (–6dB re. 200Hz) courtesy of the broad 15-120Hz port output (also –6dB). Serblin's specified 3.8ohm/5.5kHz impedance minimum is met at 3.9ohm/5.5kHz while never dropping below 6ohm from 20Hz-3kHz. As a result the sub-100Hz +45°/–57° phase angles only squeeze the EPDR down to an 'easy' 2.7ohm/110Hz with the true minimum appearing at 1.8ohm/3.4kHz. 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


The cabinet is well damped but a bass/mid-driver mode is seen at ~5kHz prior to the 10kHz peak

Sensitivity (SPL/1m/2.83V – 1kHz/Mean/IEC) 88.8dB / 87.8dB / 85.7dB
Impedance modulus: minimum & maximum (20Hz–20kHz) 3.9ohm @ 5.5kHz, 48ohm @ 80Hz
Impedance phase: minimum & maximum (20Hz–20kHz) –57° @ 88Hz, +45° @ 72Hz
Pair matching/Resp. error (200Hz–20kHz) 0.6dB/ ±4.1dB/±3.8dB
LF/HF extension (–6dB ref 200Hz/10kHz) 47Hz / 25.3kHz/24.3kHz
THD 100Hz/1kHz/10kHz (for 90dB SPL/1m) 1.5% / 0.35% / 0.5%
Dimensions (HWD) / Weight (each) 405x240x430mm / 12.5kg
Prices £8888 (+£2798 for stands)

Franco Serblin Studio
Vicenza, Italy
Supplied by: Absolute Sounds Ltd, UK
0208 971 3909