Fostex PT20K 3/4" Soft Dome Tweeter

Fostex PT20K 3/4" Soft Dome Tweeter

20 mm diameter soft dome made of newly developed UFLC* materials and a die-cast aluminum frame. Ideal for use in 2-way with PW80K, see crossover below.

• PT20K is an excellent choice of tweeter for beginners to DIY speaker-building as it can be easily combined with the sensitivity-matched woofer PW80K, with no level adjustment required (no resistor or L-pad needed on tweeter).
• UFLC* soft dome diaphragm is lightweight with high internal loss (well-damped). Its extended high frequency characteristics make for a linear response of music
• playback.
• Low distortion ferrite magnet circuit is employed. The copper cap equipped magnetic circuit reduces harmonic distortion and enables clear sound.
• The magnetic fluid-filled gap centers and controls voice coil excursion. Input durability (power handling) is also enhanced.

*UFLC material A common previous practice when producing soft domes is direct application or coating of damping materials on polyester cloth to avoid adverse effects of such materials caused by porosity or specific inherent sound on the reproduced sound. This way of production of soft domes, however, is subject to variations in the amount of applied damping materials, resulting in generation of dips in the response due to pinholes, low output level due to excessive application of damping materials, or deteriorated high end reproduction due to loss of material strength. Our new development- UFLC materials- is our solution to these problems. With it, light and highly stable diaphragms have become available. The UFLC materials consist of the following component materials:

U: Polyurethane This plastic features large internal loss, light weight and good bonding performance.
F: Film Prior processing is given to polyurethane resin to roll it to an extremely thin film of a consistent 25 µm thickness.
L: Laminated The base material and polyurethane film are pressed while heated to bond them tightly together.
C: Cloth The base material is large-meshed porous polyester cloth, chosen for its lightness and strength. The use of this UFLC material provides a 30% weight reduction and consistent quality. The dome shape of a newly developed special configuration brings about ideal performance characteristics for soft domes. The frequency response range widely and naturally extends to the extreme high end of frequencies, which had not been possible before development of this dome design, reproducing each segment of delivered sound signals to its highest fidelity.