35FR

35FR was developed as full-range ferrite magnet driver. It has an excellent HF extension and provides extended level of LF performance.
The driver was designed for usage in sealed speaker systems. It could be in column speakers, 2-way or 1-way speakers. It is also possible design a speaker system with a passive radiator to further extend the low frequency range.
Voice coil is wound with copper hi temperature wire directly on the aluminum former, ensuring good power handling and high temperature stability.
This driver brings good balance between performance and cost.
Depending on intended usage, we can deliver the driver either as 4 or 8 ohm version.

The 35FRX4-155 is a 3.5-inch full-range driver featuring a ferrite magnet motor, steel
basket, carbon fiber reinforced paper cone, NBR rubber surround, Nomex spider, and a
25.4mm copper voice coil wound on an aluminum former. It is the largest driver in the
full-range family and the only 3.5-inch variant, with an overall diameter of 93mm and
51mm mounting depth. The aluminum former provides effective heat dissipation from the
voice coil gap, supporting 25W AES / 50W continuous power handling. The manufacturer
designates this driver for sealed enclosures in column speaker, 2-way, and 1-way
applications, with passive radiator extension noted as an option for extended bass.

Enclosure alignments:
- Vented (primary) - 30 mm port:
1.5 L / Fb = 80 Hz / ~199 mm physical port / 1.51 m/s peak port velocity
2.0 L / Fb = 75 Hz / ~166 mm physical port / 1.41 m/s peak port velocity
2.5 L / Fb = 70 Hz / ~151 mm physical port / 1.32 m/s peak port velocity
(All port velocities well below the 17 m/s hi-fi limit; passive radiator is a viable
port alternative per manufacturer guidance, targeting Fp = 65-80 Hz)
- Sealed (secondary - per manufacturer intent, column / 2-way systems):
0.48 L / Qtc = 0.707 / fc = 139 Hz / f-3dB = 139 Hz
0.21 L / Qtc = 1.00 / fc = 197 Hz / f-3dB = 155 Hz
0.14 L / Qtc = 1.20 / fc = 237 Hz / f-3dB = 174 Hz

In column array applications, the 93mm driver OD limits coherent vertical directivity to
approximately 1.85 kHz - the lowest array coherence limit in the full-range family. Column
designs using this driver require a co-located tweeter to maintain coverage above 1.85 kHz,
or must accept increasing vertical beam narrowing above this frequency. The low Qts (0.34)
means the driver generates minimal back-EMF braking at resonance, so excursion limiting
below Fb in a vented enclosure is essential; a DSP high-pass filter at Fb - 10 Hz or a
subsonic filter at 50-60 Hz is recommended. Multiple units in column arrays can be wired
in series-parallel to achieve 8ohm or 16ohm loads from the nominal 4ohm driver impedance.

The 35FRX4-155 is suited for bass-extended column speaker systems where a 3.5-inch vented
enclosure delivers 70-80 Hz bass without a subwoofer; 2-way and 1-way sealed enclosures in
column, surface-mount, or wall-mount speaker products where the manufacturer-recommended
sealed alignment (0.14-0.48 L) provides predictable, compact bass rolloff above 140 Hz;
multi-way installed sound systems where the driver covers the midrange and upper bass while
a dedicated woofer handles below 150-200 Hz; and cost-sensitive applications where ferrite
motor construction and a steel basket provide a practical alternative to neodymium drivers
without compromising the core acoustic performance of the 3.5-inch format.