vSound 2 come already programmed with characterisations – known as impulse responses, or IRs – from some of the world’s most treasured violins, including models built by Stradivari, Guarneri, Tononi, Catenari, Degani and Gagliano. Working in partnership with Johannsson Violins, the characterisations of these priceless instruments are performed under the most rigorous and meticulous conditions, both in anechoic chambers and non-reverberant, acoustically controlled environments.
Acquiring an authentic impulse response requires careful measurement and attention to detail. The violin is placed in a custom-designed frame, located within the anechoic space. With the strings completely damped, the violin is lightly tapped on the bridge with a tiny measurement hammer that swings down from a bearing on the frame near the bridge. The hammer contains an integrated force sensor right at its tip, so the force delivered to the bridge can be recorded precisely. The sound that the violin makes in response to the tap is recorded by a calibrated, omnidirectional measurement microphone, located in the far-field of the instrument -typically 1.5 m from the bridge. But just recording this sound is not enough – it is vital to cancel out the effect of the hammer itself, which is done by proprietary software developed by Signal Wizard Systems.
The plot on the left shows a violin impulse response recorded from a high-quality instrument, measured under acoustically controlled conditions and compensated for the strike of the test hammer. On the right is shown its frequency response – note the extraordinary richness and complexity of the plot. Each impulse response is then checked for consistency, auto-calibrated for loudness, encrypted and programmed into the vSound 2 unit. The 24-bit core of vSound 2 ensures that every nuance of the response is faithfully replicated in the final sound output.