Purifi Audio PTT5.25X08-NFA-01

With the innovative PTT5.25X08-NFA-01, Purifi Audio presents a highly developed midrange driver that scores with key technologies for optimum audio performance. Specially optimized for midrange applications, this device features improved efficiency and negligible power factor modulation. Advantages such as very low magnetic hysteresis distortion and Purifi's unique Natural surround technology clearly set the PTT5.25X08-NFA-01 apart from the crowd. Due to the impressive long excursion performance, distortion remains minimal even at full excursion. This powerful product is manufactured by a visionary company from Denmark that understands what performance-decreasing aspects really are and how to improve them. The PTT5.25X08-NFA-01 is therefore a testament to Purifi's commitment to sound quality and precision.

• Negligible power factor modulation and distortion due to bead radiation
• Low magnetic hysteresis distortion
• "True" long-stroke performance: distortion remains low over the entire stroke
• Unadulterated performance in the mid-range
• Developed and manufactured in Denmark

The challenge

Speaker drivers are known to cause a large, if not the largest, amount of distortion in an audio signal chain. Reducing these distortions is a challenge, as fine-tuning to improve one part (e.g. harmonic distortion) often leads to a deterioration of another part (e.g. intermodulation distortion). These distortions are made up of several separate distortion mechanisms. By carefully mapping and fully understanding these mechanisms, PURIFI has succeeded in improving the overall performance to a great extent.

A completely new perspective on driver design

PURIFI developed mathematical models for the motor system, the suspension, the cone and the surround. These models made it possible to optimize each distortion mechanism separately. This systematic approach reduces all distortion mechanisms and keeps intermodulation distortion low.

• The mechanism improvement modulation with low force factor
• Improvement
• The current through the voice coil is not distorted by the diaphragm movement. Ensures an undistorted midrange regardless of the excursion
  
• Constant force factor over the deflection - Bl(x)
• Prevents amplitude deviations of the mid-range output during large excursions (sometimes referred to as "grumbling")
• Low distortion due to surround radiation Low magnetic hysteresis distortion
• Reduces harmonic and intermodulation distortion caused by the surround
• Reduces harmonic and intermodulation distortions caused by magnetic traces from the previous cycle

• PTT NFA woofer series
• Nominal diameter 13 cm
• Load capacity (QMW) 250 W
• Sensitivity (SPL at 1m / 2.83V) 85.7 dB
• Direct current resistance (Re) 3.8 Ω
• Resonant frequency (Fs) 29 Hz
• Overall quality (Qts) 0.26
• Diaphragm area (Sd) 85 cm2
• Equivalent volume (Vas) 13 L
• Maximum deflection (Xmax) 9.8 mm
• Cone / Diaphragm Material Proprietary Fibre Mix