Dedicated midrange driver with enhanced efficiency. Negligible force factor modulation. Ultra-low magnetic hysteresis distortion. Utilizes PURIFI’s neutral surround technology.

Highlights:

Negligible Force Factor Modulation and Surround Radiation Distortion

Low Magnetic Hysteresis Distortion

“Real” long-stroke performance: distortion remains low over full excursion

Uncompromised midrange performance

Designed and Manufactured in Denmark

Product Details:

PURIFI PTT5.25X04-NFA-01 Mid-range Woofer

The PTT5.25X04-NFA-01 has been optimized for Midrange use and achieves high sensitivity. PURIFI is a fresh company that designs and manufactures extremely high-performance transducers and amplifier modules. Don’t let the freshness fool you; Their leadership team consists out of some well-respected audio technology pioneers. PURIFI developed a deep understanding of many performances degrading aspects for both amplifiers and transducers. Thanks to this understanding the PTT6.5W08-NFA-01 is the most refined mid-range woofer from our woofer category.

Besides this 4 ohm version, there is also an 8 ohm version.

The challenge 

Loudspeaker drivers are known to add a large, if not the largest, amount of distortion in an audio signal chain. Reducing this distortion is a challenge with the complication of fine-tuning to improve one part (e.g. harmonic distortion) often results in a degradation of another part (e.g. intermodulation distortion). These distortions consist out of several separate distortion mechanisms. By carefully mapping and completely understanding these mechanisms, PURIFI succeeded in improving the overall performance to a large degree.

A whole new take on driver design

PURIFI developed mathematical models for the motor system, suspension, cone, and surround. These models allowed for the optimization of each distortion mechanism separately. This systematic approach reduced all distortions mechanisms and keeps intermodulation distortion low.

Specifications:

Woofer Series: PTT NFA

Nominal Diameter: 5.25”

Power Handling (RMS): 250 W

Sensitivity (SPL at 1m / 2.83V): 85.7 dB

DC Resistance (Re): 3.8 Ω

Resonant Frequency (Fs): 29 Hz

Total Q (Qts): 0.26

Surface Area of Cone (Sd): 85 cm2

Compliance Equivalent Volume (Vas): 13 L

Maximum Linear Excursion (Xmax): 9.8 mm

Cone / Diaphragm Material: Proprietary Fibre Mix