NIC - Neutral Inductance
The precision and detail of audio reproduction depend on the stability of the magnetic field.
NIC - Neutral Inductance
The precision and detail of audio reproduction depend on the stability of the magnetic field.
STABILISING THE MAGNETIC FIELD
After having pushed back the limits in electromagnetic technology, our teams discovered the fact that beyond the magnetic field intensity and its homogeneity within the gap, there was a dynamic aspect we had no control over.
The magnetic field is not stable because it is modulated by three factors:
Consequently, the voice coil, and all the moving part including the cone, is in the magnetic field which becomes too variable, and this leads to loss of precision.
NEUTRAL INDUCTANCE CIRCUIT TECHNOLOGY
After three years of research and the development of simulation software which makes it possible to visualise these complex interactions, Focal engineers created an incredibly stable magnetic circuit for the Sopra line..
The solution, NIC technology, lies in a Faraday ring whose dimensions, materials and positioning were optimised to make the magnetic field no longer affected by the position of the voice coil, by the amperage or the frequency of the current passing through it.
This is a sign of very high definition.
VISUAL ANALOGY OF MAGNETIC DISTURBANCE
Without a Faraday ring
The variations related to the position of the voice coil and to the current passing through it in a conventional circuit results in blurring.
With a conventional Faraday ring
The variations related to the position of the voice coil and to the current passing through it in a conventional circuit results in blurring.
With Focal’s Faraday ring
Our new simulation software enables us to combine the best of both worlds: very high definition and dynamics/contrast.
MEASUREMENT AND ANALYSIS
Measurements made using a Klippel Analyzer on a 6-inch midrange driver: with the new "NIC" magnetic circuit (blue trace) and a 6-inch midrange unit with a conventional ferrite motor (red trace). Left: Inductance variation as a function of the current through the voice coil, which is signal-dependent. Total stability with "NIC". Right: Inductance variation as a function of the position of the voice coil in the magnet gap. The “NIC” improvement is spectacular..
Analyzer on an 8-inch woofer: without a Faraday ring (red trace) and with a Faraday ring optimized through our simulation tool (blue trace). Left: Inductance variation as a function of the current through the voice coil, which is signal-dependent. Total stability. Right: Inductance variation as a function of the position of the voice coil in the magnet gap. The improvement here is spectacular, especially as the coil moves into the driver..
Frequency response of our latest-generation midrange driver (blue trace) compared to the previous-generation W midrange (red trace). The extension of the frequency range, resulting from all the improvements but particularly the exponential cone profile, is important as it promises improved transient response. NB: The dip at 3kHz in the blue trace is due to the tested driver not being fitted with a dust cap.
Distortion analysis using the Klippel multi-tone test signal which gives an overview of nonlinear distortion performance (harmonic and intermodulation). The lowering of distortion by about 10dB is a reduction of almost 70%.
FOCAL PRODUCTS USING THIS TECHNOLOGY