A Phase Linear Transmission Line Project

Section 1: Introduction

This speaker has been evolving around the same outer shell since the beginning of the ninties.

It started out as a Voigt line, which was built before I knew much about speakers. The drivers did not fit the design at all. The last 4 years, the speakers have been reworked several times. But the shell still remains.

The internals are now a 1.2 m transmission line based on the recommendations of the designer of the
TLB. After all this time, the current result is hard to believe.

  • The active filter with an acoustical 1st order crossover at 500Hz provides exceptional coverage
  • Baffle-step diffraction of the LF driver is handled by combining the box dimensions and the electrical filter frequency
  • HF driver diffraction is minimized utilizing a separate enclosure on top with narrow dimensions
  • Time alignment of the tweeter results in depth, width, heigth and sense of being in the concert hall
  • Low distortion aluminium drivers gives exceptional electostatic-like clarity
  • Low frequency response is remarkably good for a TL of only 1.2m. Frequencies down to 30Hz really rock the room, large symphonic music and organ are a dream on these speaker

The drivers for this design are the Jordan JX150 woofer and JX53 tweeter. The JX150 has a frequency range all the way up to 10kHz, while the JX53 can be used down to 200Hz. These are the perfect match for a 1st order system! Jordan drivers are not cheap, at $100 USD or more each. But then, these are used in systems costing several thousands.

Jordan JX150 MidBass Driver

[ Contents | Intro | Measurements | Optimization | Integration | Step Compensation | Time Align | Crossover | Construction ]