The attachment of the cones to the chassis usually consists of a foam or neoprene ring, allowing both the fixation and balance of the cone.
On the "Model 7 series", the ring of foam is removed, and with it all the problems it causes (phase rotation, acoustic short-circuit, etc.). The edge of the paper cone ends with a segment of carbon, sliding without friction in the cylinder-shaped chassis. The balance is then obtained by a network of three carbon rods.
The resonance frequency being much lower than on conventional models, and the impedance curve showing a steady level close to that frequency, the reproduction of the "low frequencies" is improved, with much better precision.
In addition, the lack of suspension avoids the problems caused by a conventional suspension, such as the seat of the production of waves being out of phase or not, depending on the operating point of the loudspeaker.
The inventor of this technology won the "innovation in small-scale industry" award, the "Stars et Métiers Languedoc-Roussillon 2010" in the technological innovation category, a competition organised by the Ecole des Mines in Alès
http://innovation.cma-languedocroussillon.fr/concours-stars-metiers/laureats-2010
| Designation | Thiele & Small | Unit | Value |
| Nominal impedance | Zn | Ohms | 8 |
| DC resistance | Rcc | Ohms | 6,2 |
| Maximum impedance at resonant frequency | Zmax | Ohms | 400 |
| Resonant frequency | FR | Hz | 24 |
| Mechanical Q | Qms | Hz | 11,2 |
| Electromagnetic Q | Qes | | 0,2 |
| Total Q | Qts | | 0,2 |
| | | | |
| Moving diaphragm mass (including air load) | Mms | kg | 0,013 |
| Effective cone area | S | M2 | 0,0179 |
| Compliance equivalent volume | Vas | M3 | 0,09 |
| BL product | BL | | 9,4 |
| Sensitivity (0 – 200 Hz) | Eff | dB | 93 |
| Maximum linear excursion | Xmax | mm | + ou - 2 |
| Acceleration factor | BL/Mms | | 732 |
| Field coil voltage | | V | 12,5 |
| Field coil current | | A | 1,5 |
| Designation | Thiele & Small | Unit | Value |
| Nominal impedance | Zn | Ohms | 8 |
| DC resistance | Rcc | Ohms | 6,2 |
| Maximum impedance at resonant frequency | Zmax | Ohms | 300 |
| Resonant frequency | FR | Hz | 22 |
| Mechanical Q | Qms | Hz | 4,6 |
| Electromagnetic Q | Qes | | 0,10 |
| Total Q | Qts | | 0,10 |
| | | | |
| Moving diaphragm mass (including air load) | Mms | kg | 0,0147 |
| Effective cone area | S | M2 | 0,0483 |
| Compliance equivalent volume | Vas | M3 | 0,336 |
| BL product | BL | | 21 |
| Sensitivity (0 – 200 Hz) | Eff | dB | 98 |
| Maximum linear excursion | Xmax | mm | + ou - 3 |
| Acceleration factor | BL/Mms | | 442 |
| Field coil voltage | | V | 12,5 |
| Field coil current | | A | 1,7 |
