Difuzor Purifi PTT5.25X04-NFA-01

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

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.

FAQ

Q: Should I go with this 4 ohm or with the 8-ohm version? 

A: Both woofers have similar distortion performance and the T/S parameters are alike. The 4 ohm coils of this PTT5.25X04-NFA-01 allows more current to flow on a similar drive voltage. This gives higher sensitivity and is preferred in most applications. If you have an amplifier that is not comfortable with low impedance loads or has specific requirements, such as parallel woofers, the PTT5.25X08-NFA-01 might be more favorable.

Q: Why is this surround odd-shaped?

A: This is the PURIFI Natural Surround. Conventional surroundings create distortion as they deform. The shape of the Natural Surround reduces cone edge resonances and distortion. It might be odd-looking, but form follows function here. A more detailed look shows that the surround actually represents a complex sound wave. We are told that the Natural Surround is also called ‘wormy’ by insiders.