Franco Serblin Accordo loudspeaker Lab Report

Were the Accordo to achieve its specified 87dB sensitivity it would be a surprise for so diminutive a cabinet, so it was predictable that it shouldn’t. Our pink noise figure of 85.1dB (200Hz-20kHz) is much more in line with expectations for a standmount speaker of this size. Franco Serblin could have opted to increase it a little by lowering the impedance further but appears to have chosen to keep the Accordo relatively easy to drive. Our measured minimum of 4.1ohm is slightly above the specified nominal figure of 4ohm, which is unusual, and impedance phase angles are sufficiently well controlled, particularly at low frequencies, that the EPDR (equivalent peak dissipation resistance) bottoms out at 2.2ohm/127Hz, although a second dip to 2.4ohm/457Hz complicates the issue.


The Accordo’s response shows a slightly recessed presence band but a bright treble thereafter


The solid little cabinet is well damped but driver resonances are visible through the treble >4kHz

Forward frequency responses for the review pair, measured at a distance of 1m on the tweeter axis, show a slightly downward trend [see Graph 1] through the presence band after which there is narrow 4dB suckout near 5kHz and shelved up upper-treble output thereafter. Response errors are a little high at ±4.4dB and ±3.9dB, respectively, as is the pair matching error of ±1.3dB over the same 200Hz-20kHz frequency range. Diffraction correction for such an unusual cabinet shape is difficult but our nearfield measurement of bass response shows its extension to reach 62Hz (–6dB re. 200Hz) rising a little to 70Hz with the foam port bungs inserted. High distortion at 100Hz was to be expected given the diameter of the bass-mid driver but 1.5% at 1kHz (90dB/1m) was still disappointing. The measurement was repeated with the same result. The CSD waterfall [Graph 2] reveals a series of treble resonances. KH

Sensitivity (SPL/1m/2.83Vrms – Mean/IEC/Music): 86.1dB / 85.1dB / 84.5dB
Impedance modulus min/max (20Hz–20kHz): 4.1ohm @ 192Hz / 33.6ohm @ 2.4kHz
Impedance phase min/max (20Hz–20kHz): –48° @ 104Hz / 52° @ 1.3kHz
Pair matching/Response Error (200Hz–20kHz): ±1.3dB / ±4.4dB / ±3.9dB
LF/HF extension (–6dB ref 200Hz/10kHz): 62Hz / 33.2kHz / 31.3kHz
THD 100Hz/1kHz/10kHz (for 90dB SPL/1m): 1.8% / 1.5% / 0.3%
Dimensions (HWD): 360x190x360mm
Price: £7500

Franco Serblin Studio
Vicenza, Italy
Supplied by: Absolute Sounds Ltd, UK
0045 9684 5100