TECHNOLOGY

App Notes & Downloads

Dec 20th, 2019

SPK5 – App Note (Replaces SPK4 – App Note)

read more

SPK5 is intended as demonstration platform for the PTT6.5W04-01A transducer.
The design is deliberately kept very simple: a small ported wooden box, traditionally shaped with a simple 12.5mm chamfer for management of edge diffraction, and a passive cross over at ~3.2kHz. Although extremely simple, with numerous possibilities for enhancement by the skilled speaker designer, the SPK5 design very successfully demonstrates the tremendous improvements in sound quality which is possible to achieve when using the long-stroke ultra-low-distortion PTT6.5W04 woofer from PURIFI Transducer Technology.

p-logo

Nov 11th, 2019

SPK4 – App Note

read more

SPK4 is intended as demonstration platform for the PTT6.5W04-01A transducer.
The design is deliberately kept very simple: a small ported wooden box, traditionally shaped with no particular management of edge diffraction, and a passive cross over at ~2.5kHz. Although extremely simple, with numerous possibilities for enhancement by the skilled speaker designer, the SPK4 design very successfully demonstrates the tremendous improvements in sound quality which is possible to achieve when using the long-stroke ultra-low-distortion PTT6.5W04 woofer from PURIFI Transducer Technology.

p-logo

Sep 29th, 2016

Force Factor Modulation in Electro Dynamic Loudspeakers

read more

The relationship between the non-linear phenomenon of ’reluctance force’ and the position dependency of the
voice coil inductance was established in 1949 by Cunningham, who called it ’magnetic attraction force’. This paper
revisits Cunningham’s analysis and expands it into a generalised form that includes the frequency dependency and
applies to coils with non-inductive (lossy) blocked impedance. The paper also demonstrates that Cunningham’s
force can be explained physically as a modulation of the force factor which again is directly linked to modulation
of the flux of the coil. A verification based on both experiments and simulations is presented along discussions of
the impact of force factor modulation for various motor topologies. Finally, it is shown that the popular L2R2 coil
impedance model does not correctly predict the force unless the new analysis is applied.

p-logo