Product Description
The 2022 MT Series of Fi subwoofers is designed to meet the needs of the serious competitor and and monster basshead. With a massive 4″ voicecoil for increase thermal capacity, we designed the rest of the motor via FEA to optimize the proprietary US steel (water jet and machined in house at Fi when your order is placed). Using three ultra-high grade Y35 magnets, a flux flow derived back plate geometry, and a solid pole with aluminum sleeve and aluminum compression cap, there is plenty of thermal capacity in the MT Series. Our Fi designed heavy 5 spider pack coupled with our special 144 tinsel count leadwire to keep the moving assembly under control at extreme excursion levels. The reworked surround geometry on the 12″, 15″, and 18″ models optimizes cone area vs excursion yielding the most output vs excursion. The 2022 MT Series is designed for competition use and monster daily driving systems requiring high linearity and extreme power handling. From a punishing low end to the subtle nuances in your favorite reference track, the MT Series delivers!
The MT Series allows for 2 stages of cooling and inductance mitigation.
STAGE 1: Is a machined aluminum pole sleeve that reduces inward coil inductance shift and helps linearize overall inward vs outward inductance reducing distortion. This sleeve also aids in heat wicking to the pole as aluminum has a significantly better thermal coefficient than steel alone does.
STAGE 2: Uses both the pole sleeve and an aluminum pole cap to increase compression and cooling. Also, via its profile and increased aluminum around the coil as it gets closer to the pole itself, inductance is further reduced. As a coil moves inward its inductance increases relative to the steel it surrounds, so the closer the coil is to steel, the more aluminum you would want in proximity to it. As inductance is the natural resistance to directional change, reducing and linearizing it increases output range and can ease some amplifiers operation.
Features
Dual 1 and Dual 2 Ohm
Extra heavy aluminum basket
Wrap around gasket
Kraft pulp fiber reinforced cone
Dual layer wide foam surround
Standard heavy duty stitched Push or Hybrid terminals
144 tinsel count leads
FEA optimized motor design
Ultra Flux density design
4” diameter 4 layer coil
Triple stack magnets
Carbon cap standard
Stage 2 Aluminum Cooling
Water jet and machined in house from US steel
Five extreme 10″ spiders
6″ Gloss Carbon dustcap
Thiele-Small Parameters
| MT 12 | MT 15 | MT 18 | |
|---|---|---|---|
| Coils | DUAL 1 | DUAL 2 | DUAL 1 | DUAL 2 | DUAL 1 | DUAL 2 |
| FS | 34.3 Hz | 34.3 Hz | 32.2 Hz | 32.6 Hz | 31.7 Hz | 32.1 Hz |
| RE | 0.75 | 1.49 | 0.75 | 1.49 | 0.75 | 1.49 |
| QMS | 7.93 | 7.83 | 8.52 | 8.43 | 9.91 | 9.79 |
| QES | 0.36 | 0.38 | 0.38 | 0.40 | 0.45 | 0.47 |
| QTS | 0.35 | 0.37 | 0.37 | 0.38 | 0.43 | 0.45 |
| MMS | 408g | 404g | 444g | 435g | 516g | 503g |
| CMS | 0.53 | 0.53 | 0.53 | 0.53 | 0.68 | 0.68 |
| SD | 480cm^2 | 480cm^2 | 810cm^2 | 810cm^2 | 1210cm^2 | 1210cm^2 |
| VAS | 17.17 l | 17.17 l | 49.0 l | 49.0 l | 95.4 l | 95.4 l |
| SPL | 84.6dB | 84.4dB | 88.1dB | 88.1dB | 90.2dB | 90.1dB |
| BL | 19 N/A | 26.1 N/A | 19 N/A | 26.1 N/A | 19 N/A | 26.1 N/A |
| XMAX | 33mm (One Way) | 33mm (One Way) | 33mm (One Way) |
| RMS | 4500W | 4500W | 4500W |
Technical Specifications
| MT 12 | MT 15 | MT 18 | |
|---|---|---|---|
| Overall Diameter | 12.500” | 15.625” | 18.500” |
| Cutout Diameter | 11.125” | 14.125” | 16.750” |
| Mounting Depth | 10.00” | 11.00” | 12.250” |
| Driver Displacement | 0.19cuft | 0.21cuft | 0.26cuft |
| Ported Box | 1.8-2.5 cuft | 3-5 cuft | 5-8 cuft |
